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  Subjects -> COMPUTER SCIENCE (Total: 1993 journals)
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COMPUTER SCIENCE (1157 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 13)
Abakós     Open Access   (Followers: 3)
Academy of Information and Management Sciences Journal     Full-text available via subscription   (Followers: 69)
ACM Computing Surveys     Hybrid Journal   (Followers: 22)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 9)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 11)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 13)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 3)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 1)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 20)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 8)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 8)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 11)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 21)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26)
Advanced Science Letters     Full-text available via subscription   (Followers: 7)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 16)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Computer Science : an International Journal     Open Access   (Followers: 13)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 53)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Human-Computer Interaction     Open Access   (Followers: 20)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 37)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 1)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 6)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 7)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 4)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 7)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 9)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annual Reviews in Control     Hybrid Journal   (Followers: 6)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applied and Computational Harmonic Analysis     Full-text available via subscription   (Followers: 2)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 14)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Computer Systems     Open Access   (Followers: 1)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 32)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 125)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 6)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Computer Science and Information Technology     Open Access  
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access  
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 3)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 9)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Bioinformatics     Hybrid Journal   (Followers: 307)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 46)
British Journal of Educational Technology     Hybrid Journal   (Followers: 124)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 2)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
Cell Communication and Signaling     Open Access   (Followers: 1)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access  
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 12)
Circuits and Systems     Open Access   (Followers: 16)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Communication Methods and Measures     Hybrid Journal   (Followers: 11)
Communication Theory     Hybrid Journal   (Followers: 20)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 53)
Communications of the Association for Information Systems     Open Access   (Followers: 18)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access  
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 14)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Research     Open Access   (Followers: 1)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 13)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 31)
Computer     Full-text available via subscription   (Followers: 84)
Computer Aided Surgery     Hybrid Journal   (Followers: 3)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 7)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 22)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 10)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 1)
Computer Music Journal     Hybrid Journal   (Followers: 16)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computer Science and Information Technology     Open Access   (Followers: 11)
Computer Science Education     Hybrid Journal   (Followers: 12)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Master Research     Open Access   (Followers: 10)
Computer Science Review     Hybrid Journal   (Followers: 10)

        1 2 3 4 5 6 | Last

Journal Cover ChemSusChem
  [SJR: 2.649]   [H-I: 88]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1864-5631 - ISSN (Online) 1864-564X
   Published by John Wiley and Sons Homepage  [1577 journals]
  • Reactive electrophilic OI--species evidenced in high-performance
           Ir-oxohydroxide water oxidation electrocatalysts
    • Authors: Cyriac Massué; Verena Pfeifer, Maurice Van Gastel, Johannes Noack, Gerardo Algara-Siller, Sebastien Cap, Robert Schlögl
      Abstract: Although quasi-amorphous Ir-oxohydroxides haverepeatedly been identified as superior oxygen evolution reaction(OER) electrocatalysts, an exact description of the performance relevantspecies has so far remained a challenge. In this context, wereport on the characterization of hydrothermally prepared IrIII/IV oxohydroxides exhibiting exceptional OER-performance. It was foundthat holes in the O2p states of IrIII/IV-oxohydroxides result in reactiveOI--species identified by characteristic NEXAFS-features. Aprototypical titration reaction based on CO as a probe molecule showsthat these OI--species are highly susceptible to nucleophilic attack atroom temperature. Similarly to pre-activated oxygen involved in thebiological OER in Photosystem II, the electrophilic OI--speciesevidenced in IrIII/IV-oxohydroxides are suggested to be precursors tospecies involved in the O-O bond formation during electrocatalyticOER. CO-titration also highlights a link between OER-performanceand the surface/sub-surface mobility of OI--species. The superiorelectrocatalytic properties of IrIII/IV-oxohydroxides are thus explainedby their ability to accommodate pre-activated electrophilic OI--speciesable to migrate within the lattice.
      PubDate: 2017-09-21T03:21:02.885574-05:
      DOI: 10.1002/cssc.201701291
       
  • BiVO4 Fern Architectures: A Competitive Anode for Li-ion Batteries
    • Authors: Deepak Dubal; Deepak Patil, Santosh Patil, N. R. Munirathnam, Pedro Gomez-Romero
      Abstract: The search of high-performance anode materials for Lithium-ion batteries (LIBs) is currently one of the most important tasks. Herein, we are introducing BiVO4 fern architectures as a new anode material for LIBs. The BiVO4 fern shows an excellent reversible capacity of 769 mAh/g (ultrahigh volumetric capacity of 3984 mAh/cm3) at 0.12 A/g with a great capacity retention. Later, a LIB full cell is assembled with BiVO4 ferns as anode and LiFePO4 (LFP, commercial) as cathode material. Notably, the device can achieve the capacity of 140 mAh/g at 1C rate that is 81 % of the capacity of cathode and maintained to 104 mAh/g at high C-rate of 8C, which makes BiVO4 a promising candidate as high-energy anode materials for LIBs.
      PubDate: 2017-09-21T00:15:54.24716-05:0
      DOI: 10.1002/cssc.201701483
       
  • Imidazolium Ions with an Alcohol Substituent for Enhanced Electrocatalytic
           Reduction of CO2
    • Authors: Xianbo Jin; Lin Zhang, Nian Wu, Jichen Zhang, Yang Hu, Zhiyong Wang, Lin Zhuang
      Abstract: Electrochemical reduction of CO2 to CO is attractive for carbon dioxide reduction, energy regeneration and storage. Imidazolium Ionic liquids (IMILs) are promising electrolyte catalysts for this important reaction. Herein we report functionalizing the imidazolium ion with a propanol substituent at the N site can significantly enhance the catalytic activity of IMILs, causing a positive shift of the onset potential for the CO2 reduction by about 90 mV in an acetonitrile electrolyte. Theoretical calculation indicated that the propanol hydroxyl could bridge a local hydrogen bonding chain as shortcut for proton transfer, leading to a dramatic decrease of the activation barrier for the IMIL-catalytic reduction of CO2.
      PubDate: 2017-09-20T04:20:22.109872-05:
      DOI: 10.1002/cssc.201701673
       
  • Enhancing Photocurrent Generation in Photosynthetic Reaction Center-based
           Photoelectrochemical Cells with Biomimetic DNA Antenna
    • Authors: Anne-Marie Carey; Haojie Zhang, Minghui Liu, Daiana Sharaf, Natalie Akram, Hao Yan, Su Lin, Neal Woodbury, Dong-Kyun Seo
      Abstract: 3 to 4 times higher performance of biohybrid photoelectrochemical cells with photosynthetic reaction centers (RC) has been achieved by using a DNA-based biomimetic antenna. Synthetic dyes Cy3 and Cy5 were chosen and strategically placed in the anntena in such a way that they can collect additional light energy in the visible region of the solar spectrum and transfer it to RC through Förster resonance energy transfer (FRET). The antenna, a DNA templated multiple dye system, is attached to each Rhodobacter sphaeroides RC near the primary donor, P, to facilitate the energy transfer process. Excitation with a broad light spectrum (approximating sunlight) triggers a cascade of excitation energy transfer from Cy3 to Cy5 to P, and also directly from Cy5 to P. This additional excitation energy increases RC absorbance cross-section in the visible and thus, the performance of the photoelectrochemical cells. DNA-based biomimetic antennas offer a tunable, modular light-harvesting system for enhancing RC solar coverage and performance for photoelectrochemical cells.
      PubDate: 2017-09-19T20:51:03.01933-05:0
      DOI: 10.1002/cssc.201701390
       
  • NIR Absorbing Metal-Free Organic, Porphyrin, and Phthalocyanine Dyes for
           Panchromatic DSCs
    • Authors: Phillip Brogdon; Hammad Cheema, Jared Heath Delcamp
      Abstract: Dye-sensitized solar cells (DSCs) are a promising source of renewable energy. However, power conversion efficiency (PCE) of devices has been limited largely by the difficulty of producing electricity using photons from the near-infrared (NIR) spectral region. Metal-free organic sensitizers frequently employ strong electron donating or withdrawing moieties to tune the optical band gap to allow the absorption of lower energy wavelengths in charge transfer systems while porphyrins and phthalocyanines use substituents to shift the Soret and Q bands toward lower energy absorption. Very few devices employing precious metal free dyes have been able to achieve panchromatic, NIR photon conversion for electricity generation at wavelengths>750 nm despite a tremendous number of sensitizers published over last 25 years. This minireview seeks to compile a summary of these sensitizers to encourage assimilation, analysis and development of efficient future NIR sensitizers. Herein, we discuss common synthetic strategies, optical properties and electronic properties of the most successful panchromatic organic sensitizers in this regard.
      PubDate: 2017-09-19T13:40:32.723807-05:
      DOI: 10.1002/cssc.201701441
       
  • A Strategy for Simultaneous Synthesis of Methallyl Alcohol and Diethyl
           Acetal with Sn-β
    • Authors: Wenda Hu; Yan Wan, Lili Zhu, Xiaojie Cheng, Shaolong Wan, Jingdong Lin, Yong Wang
      Abstract: Herein we report a strategy to simultaneously produce two important chemicals namely Methallyl alcohol (Mol) and diethyl acetal (Dal) from methacrolein (Mal) in ethanol solvent at low temperature with the use of Beta zeolites modified by tin (Sn-β catalysts). All Sn-β catalysts were prepared by the solid-state ion-exchange (SSIE) method, wherein the calcination step was conducted in different gas atmospheres. The one pre-calcined in Ar (Sn-β-Ar) diminishes the number of extra-framework Sn species and instead enables more Sn species exchanged into the framework as isolated tetrahedral Sn (IV), thus enhancing the catalytic activity of Meerwein-Ponndorf-Verley (MPV) reaction. The sodium-exchanged Sn-β-Ar, with the weak Brønsted acid site further diminished, leads to an even better result to Mol, thanks to the restriction of those side reactions such as acetalization, addition and etherification. Under optimized catalyst and reaction condition, the yield of Mol and Dal could reach about 90% and 96%, respectively. The possible reaction pathway, along with the complex network of side products, was proposed after a detailed investigation through the use of different substrates as the reactants. The findings of Sn-β fine-tuned through different treatment in this work, are of great significance toward understanding and manipulating the complex reaction between ɑ, β-unsaturated aldehydes and primary alcohols.
      PubDate: 2017-09-19T07:40:44.303221-05:
      DOI: 10.1002/cssc.201701435
       
  • Ring-Opening Polymerization of L-Lactide to Cyclic Poly(Lactide) by
           Zeolitic Imidazole Framework-8 Catalyst
    • Authors: Zhixiong Luo; Somboon Chaemchuen, Kui Zhou, Francis Verpoort
      Abstract: The catalytic activity of ZIF-8 in the ring-opening polymerization of L-lactide without solvents or co-catalysts is presented for the first time. Two different synthetic strategies have been applied for synthesizing ZIF-8, either under solvothermal condition or by spray-drying procedure. Their catalytic activities are found to be correlating with the presence of open active sites in ZIF-8 structure. The structural defects which afford active acid and basic sites are supposed to cooperatively catalyze the reaction. ZIF-8 assembled by spray-drying technique, displays a superior catalytic activity at temperature of 160 °C, leading to the formation of high molecular weight cyclic polylactide. The ZIF-8 catalysts could be recycled and reused without any significant loss of catalytic activity.
      PubDate: 2017-09-18T21:45:33.605983-05:
      DOI: 10.1002/cssc.201701438
       
  • Catalyst stability benchmarking for the oxygen evolution reaction - the
           importance of backing electrode material and dissolution in accelerated
           aging studies
    • Authors: Simon Geiger; Olga Kasian, Andrea M. Mingers, Shannon S. Nicley, Ken Haenen, Karl J. J. Mayrhofer, Serhiy Cherevko
      Abstract: In searching for alternative oxygen evolution reaction (OER) catalysts for acidic water splitting, fast screening of materials intrinsic activity and stability in half-cell tests is of vital importance. It significantly accelerates the discovery of new promising materials without the need of time-consuming real cell analysis. In commonly employed tests, a conclusion on the catalyst stability is drawn solely on the basis of pure electrochemical information, e.g. by evaluating potential vs. time profiles. In this work we demonstrate important limitations of such approaches, which are related to the degradation of the backing electrode material. For this purpose we use state-of-the-art Ir-black powder and investigate its OER activity and dissolution as a function of the backing electrode material. We show that even at very short time intervals materials like glassy carbon passivate, increasing the contact resistance and concealing the degradation phenomena of the electrocatalyst itself. Alternative backing electrodes like gold and boron doped diamond show a better stability and are thus recommended for short accelerated aging investigations. Moreover, parallel quantification of dissolution products in the electrolyte is shown to be of great importance for a solid comparison of OER catalyst feasibility.
      PubDate: 2017-09-18T11:45:25.259895-05:
      DOI: 10.1002/cssc.201701523
       
  • Anion Exchange Membranes for Alkaline Fuel Cell Applications: The Effects
           of Cations
    • Authors: Zhe Sun; Bencai Lin, Feng Yan
      Abstract: Alkaline anion exchange membrane fuel cells (AEMFCs) are attracting great attention, because of their potential use of non-precious electrocatalysts. Anion exchange membrane (AEM) is one of the key components of AEMFCs. An ideal AEM should possess high hydroxide conductivity and sufficient long-term durability at elevated temperatures in high pH solutions. This review provides recent progresses of alkaline stability behavior of cations (including quaternary ammonium, imidazolium, guanidinium, pyridinium, tertiary sulfonium, phosphonium, benzimidazolium and pyrrolidinium) and their analogous AEMs, which have been investigated by both experimental studies and theoretical calculations. Effects, including conjugated effect, steric hindrance effect, σ−π hyperconjugative effect and electron effect on the alkaline stability of cations and their analogous AEMs have been discussed. The attempt of this article is to give an overview of some key factors, for future design of novel cations, and their analogous AEMs with high alkaline stability.
      PubDate: 2017-09-18T10:40:40.577073-05:
      DOI: 10.1002/cssc.201701600
       
  • Mechanistic parameters of electrocatalytic water oxidation on LiMn2O4 in
           comparison to natural photosynthesis
    • Authors: Lennart Köhler; Majid Ebrahimizadeh Abrishami, Vladimir Roddatis, Janis Geppert, Marcel Risch
      Abstract: Targeted improvement of the low efficiency of water oxidation during the oxygen evolution reaction (OER) is severely hindered by insufficient knowledge of the electrocatalytic mechanism on heterogeneous surfaces. We chose LiMn2O4 as a model system for mechanistic investigations as it shares the cubane structure with the active site of photosystem II and the valence of Mn3.5+ with the dark-stable S1 state in the mechanism of natural photosynthesis. The investigated LiMn2O4 nanoparticles are electrochemically stable in NaOH electrolytes and show respectable activity in any of the main metrics. At low overpotential, the key mechanistic parameters of Tafel slope, Nernst slope and reaction order have constant values of 62(1) mV dec-1, 1(1) mV pH-1 (RHE), -0.04(2) (RHE), respectively. These values are interpreted in the context of the well-studied mechanism of natural photosynthesis. The uncovered difference in the reaction sequence is important for the design of efficient bio-inspired electrocatalysts.
      PubDate: 2017-09-18T05:40:49.544189-05:
      DOI: 10.1002/cssc.201701582
       
  • Dehydrogenase-Catalyzed Oxidation of Furanics: Exploitation of Hemoglobin
           Catalytic Promiscuity
    • Authors: Hao-Yu Jia; Min-Hua Zong, Hui-Lei Yu, Ning Li
      Abstract: The Inside Cover picture shows a new and effective in situ regeneration system for oxidized nicotinamide cofactors [NAD(P)+] based on catalytic promiscuity of hemoglobin (Hb). This NAD(P)+ regeneration system has good applicability in oxidation reactions catalyzed by dehydrogenases (DHs) such as horse liver alcohol dehydrogenase (HLADH). The target acids (e.g., 2,5furandicarboxylic acid, FDCA) were prepared from bio-based furanics with moderate-to-good yields in the Hb/HLADH parallel cascade reactions. More details can be found in the Communication by Jia et al. (
      DOI : 10.1002/cssc.201701288).
      PubDate: 2017-09-18T04:41:39.600488-05:
       
  • Strongly Coupled Molybdenum Carbide on Carbon Sheets as a Bifunctional
           Electrocatalyst for Overall Water Splitting
    • Authors: Hao Wang; Yingjie Cao, Cheng Sun, Guifu Zou, Jianwen Huang, Xiaoxiao Kuai, Jianqing Zhao, Lijun Gao
      Abstract: Invited for this month′s cover is the group of Prof. Lijun Gao in the Soochow Institute for Energy and Materials InnovationS (SIEMIS) at Soochow University. The image shows the overall water splitting catalyzed by a Mo2C-based bifunctional electrocatalyst. The Full Paper itself is available at 10.1002/cssc.201701276.“For the first time, we developed carbide-based bifunctional catalysts…” This and more about the story behind the research that inspired the Cover image is presented in the Cover Profile. Read the full text of the corresponding research at 10.1002/cssc.201701276. View the Front Cover here: 10.1002/cssc.201701699.
      PubDate: 2017-09-18T04:41:32.49524-05:0
      DOI: 10.1002/cssc.201701700
       
  • Highly Active N,O Zinc Guanidine Catalysts for the Ring-Opening
           Polymerization of Lactide
    • Authors: Pascal M. Schäfer; Martin Fuchs, Andreas Ohligschläger, Ruth Rittinghaus, Paul McKeown, Enver Akin, Maximilian Schmidt, Alexander Hoffmann, Marcel A. Liauw, Matthew D. Jones, Sonja Herres-Pawlis
      Abstract: The Back Cover picture shows our new zinc carboxyguanidine catalyst for the ring-opening polymerization of lactide to polylactide (PLA), a biodegradable polyester. Lactide originates from maize, sugar beets, or sugar cane as renewable resources. PLA is well-known but up to now industrially produced only by tin catalysts. Our catalyst represents a viable alternative for the melt polymerization (monitored by Raman spectroscopy) owing to its extraordinary robustness and activity. More details can be found in the Full Paper by Schäfer et al. (
      DOI : 10.1002/cssc.201701288).
      PubDate: 2017-09-18T04:41:19.451274-05:
       
  • Strongly Coupled Molybdenum Carbide on Carbon Sheets as a Bifunctional
           Electrocatalyst for Overall Water Splitting
    • Authors: Hao Wang; Yingjie Cao, Cheng Sun, Guifu Zou, Jianwen Huang, Xiaoxiao Kuai, Jianqing Zhao, Lijun Gao
      Abstract: The Cover picture shows a new bifunctional electrocatalyst of strongly coupled molybdenum carbide on carbon sheets (Mo2C@CS) toward overall water splitting. Benefitting from the synergistic advantages of active sites on basal planes, high surface area, and unique lamellar structure of supporting carbon sheets, the resulting Mo2C@CS exhibits superior electrocatalytic activity for both hydrogen and oxygen evolution reactions as well as excellent stability. Remarkably, the composite is able to serve as both anode and cathode catalyst for the two-electrode water electrolyzer. More details can be found in the Full Paper by Wang et al. (
      DOI : 10.1002/cssc.201701276).
      PubDate: 2017-09-18T04:35:20.087504-05:
       
  • Enhanced formation of>C1 products in the electroreduction of CO2 by adding
           a carbon dioxide adsorption component to a gas diffusion layer-type
           catalytic electrode
    • Authors: Bhanu Chandra Marepally; Claudio Ampelli, Chiara Genovese, Tapish Saboo, Siglinda Perathoner, Florian M. Wisser, Laurent Veyre, Jérôme Canivet, Elsje Alessandra Quadrelli, Gabriele Centi
      Abstract: The addition of a CO2 adsorption component (substituted imidazolate-based SIM-1 crystals) to a gas diffusion layer (GDL) type catalytic electrode allows to enhance the activity and especially the selectivity to>C1 carbon chain products (ethanol, acetone and isopropanol) of a Pt-based electrocatalyst that is not able to form products of CO2 reduction involving C-C bond formation under conventional (liquid-phase) conditions. This indicates that the increase of the CO2 effective concentration at the electrode active surface is the factor controlling the formation of>C1 products rather than only the intrinsic properties of the electrocatalyst.
      PubDate: 2017-09-18T03:41:36.923837-05:
      DOI: 10.1002/cssc.201701506
       
  • Polaronic charge carrier - lattice interaction in lead halide perovskites
    • Authors: Christoph Wolf; Young-Hoon Kim, Himchan Cho, Tae-Woo Lee
      Abstract: Almost ten years after the renaissance of the popular perovskite-type semiconductors based on lead-salts with general formula AMX3 (A=organic or inorganic cation, M=divalent metal, X=halide), many facets of photophysics continue to puzzle researchers. In this review, we shed some light on the low mobilities of charge carriers in lead-halide perovskites with special focus on the lattice properties at non-zero temperature. The polar and soft lattice leads to pronounced electron-phonon coupling, limiting carrier mobility and retarding recombination. We propose that the proper picture of excited charge carriers at temperature ranges that are relevant for device operations is that of a polaron, with Fröhlich coupling constants between 1
      PubDate: 2017-09-18T00:15:21.889289-05:
      DOI: 10.1002/cssc.201701284
       
  • Natural and Artificial Mn4Ca-cluster for Water-Splitting Reaction
    • Authors: Chunxi Zhang; Changhui Chen, Yanxi Li, Guoqing Zhao, Ruoqing Yao
      Abstract: The oxygen-evolving center (OEC) in photosystem II (PSII) is a unique biological catalyst that splits water into electrons, protons and O2 by using solar energy. Recent crystallographic studies have revealed that the structure of the OEC is an asymmetric Mn4Ca-cluster, which provides a blueprint to develop man-made water-splitting catalysts in artificial photosynthesis. Although it is a great challenge to mimic the whole structure and function of the OEC in the laboratory, significant advances have recently been achieved. Recent progress on mimicking of the natural OEC is now reviewed and discussed. New strategies are suggested to construct more stable and efficient new generation of catalytic materials for the water-splitting reaction based on the artificial Mn4Ca-cluster in the future.
      PubDate: 2017-09-17T21:31:04.71808-05:0
      DOI: 10.1002/cssc.201701371
       
  • Stupendous Role of Co-sensitizers in Dye Sensitized Solar Cells
    • Authors: Lingamallu Giribabu; Vamsi Krishna Narra, Venkata Suman Krishna Jonnadula, Mrinalini Madoori, Prasanthkumar Seelam
      Abstract: Co-sensitization in dye sensitized solar cells (DSSCs) received significant attention for improving the efficiency and stability of renewable energy resources. In this context, ruthenium metal and porphyrin dyes based DSSCs achieved increment in power conversion efficiency (PCE) from 8 - 11% to 11-14% after addition of additives, co-adsorbents and co-sensitizers by reducing the aggregation and charge recombination. Among the three supporting materials, co-sensitizers played major role to enhance the performance and stability of DSSCs which assist in commercialization. In this review, we highlighted the importance of co-sensitizers in photovoltaic performance of ruthenium metal and porphyrin dye based solar cells. Consequently, co-sensitizers are rather important to modulate the PCE of DSSCs and find realistic future practical applications.
      PubDate: 2017-09-16T04:20:22.917607-05:
      DOI: 10.1002/cssc.201701224
       
  • Chemoselective and catalyst-free O-borylation of silanols: a facile access
           to borasiloxanes
    • Authors: Krzysztof Kuciński; Grzegorz Hreczycho
      Abstract: This paper demonstrates, for the first time, a highly chemoselective synthesis of various borasiloxanes from hydroboranes and silanols which was achieved through a catalyst-free dehydrogenative coupling at room temperature. This green protocol, which uses easily accessible reagents, allows for the obtaining of borasiloxanes under air atmosphere and solvent-free conditions.
      PubDate: 2017-09-15T12:21:01.830659-05:
      DOI: 10.1002/cssc.201701648
       
  • Corrigendum: Catalytic Biodiesel Production Mediated by Amino Acid-Based
           Protic Salts
    • Authors: Jingbo Li; Zheng Guo
      PubDate: 2017-09-15T06:10:07.604155-05:
      DOI: 10.1002/cssc.201701703
       
  • Fuel Production from Seawater and Fuel Cells Using Seawater
    • Authors: Shunichi Fukuzumi; Yong-Min Lee, Wonwoo Nam
      Abstract: Seawater is the most abundant resource on our planet and fuel production from seawater has the remarkable merit that it would not compete with growing demands of pure water. This review focuses on the production of fuels from seawater and their direct use in fuel cells. Electrolysis of seawater under appropriate conditions affords hydrogen and dioxygen with 100% Faradaic efficiency without oxidation of chloride ion. Photoelectrocatalytic production of hydrogen from seawater provides promising way to produce hydrogen with low cost and high efficiency. Microbial solar cells (MSCs) using biofilms produced in seawater can generate electricity from sun light without additional fuel because the products of photosynthesis can be utilized as electrode reactants, while the electrode products can be utilized as photosynthetic reactants. Another important source for hydrogen is hydrogen sulfide, which is abundantly found in Black Sea deep water. Hydrogen is produced by electrolysis of Black Sea deep water that can also be used in hydrogen fuel cells. Production of a fuel and its direct use in a fuel cell has been made possible for the first time by combination of photocatalytic production of hydrogen peroxide from seawater and dioxygen in the air and its direct use in one-compartment hydrogen peroxide fuel cells to obtain electric power.
      PubDate: 2017-09-15T04:20:27.485191-05:
      DOI: 10.1002/cssc.201701381
       
  • Application of Pulse Radiolysis to Mechanistic Investigations of Catalysis
           Relevant to Artificial Photosynthesis
    • Authors: Etsuko Fujita; David C Grills, Dmitry E Polyansky
      Abstract: Taking inspiration from natural photosystems, the goal of artificial photosynthesis is to harness solar energy to convert abundant materials, such as CO2 and H2O, into solar fuels. Catalysts are required to ensure that the necessary redox half-reactions proceed in the most energy-efficient manner. It is therefore critical to gain a detailed mechanistic understanding of these catalytic reactions in order to develop new and improved catalysts. Many of the key catalytic intermediates are short-lived transient species, requiring time-resolved spectroscopic techniques for their observation. The two main methods for rapidly generating such species on the sub-microsecond timescale are laser flash photolysis and pulse radiolysis. These methods complement one another, and both can provide important spectroscopic and kinetic information. However, pulse radiolysis proves to be superior in systems with significant spectroscopic overlap between photosensitizer and other species present during the reaction. Here, we review the pulse radiolysis technique and how it has been applied to mechanistic investigations of half-reactions relevant to artificial photosynthesis.
      PubDate: 2017-09-12T15:15:25.440615-05:
      DOI: 10.1002/cssc.201701559
       
  • Green and sustainable route to carbohydrate vinyl ethers for accessing
           bio-inspired materials with a unique microspherical morphology
    • Authors: Konstantin Rodygin; Irina Werner, Valentine P. Ananikov
      Abstract: Synthesizing chemicals and materials based on renewable sources is one of the main tasks of modern science. Carbohydrates represent excellent renewable natural raw materials, that are eco-friendly, inexpensive and biologically compatible. Herein, we developed a green vinylation procedure for carbohydrates using readily available calcium carbide. Various carbohydrates were utilized as starting materials resulting in mono-, di- and tetra-vinyl ethers in high to excellent yields (81-92 %). The synthesized bio-based vinyl ethers were utilized as monomers in free radical and cationic polymerizations. A unique combination of smooth surface and intrinsic microcompartments was achieved in the synthesized materials. Two types of bio-based materials were prepared involving microspheres and "Swiss cheese" polymers. Scanning electron microscopy with built-in ion beam cutting was applied to reveal the spatial hierarchical structures in three-dimensional space.
      PubDate: 2017-09-12T05:21:44.227869-05:
      DOI: 10.1002/cssc.201701489
       
  • Rational Development of Neutral Aqueous Electrolytes for Zinc-Air
           Batteries
    • Authors: Simon Clark; Arnulf Latz, Birger Horstmann
      Abstract: Neutral aqueous electrolytes have been shown to extend both the calendar-life and cycling stability of secondary zinc-air batteries (ZABs). Despite this promise, there are currently no modeling studies investigating the performance of neutral ZABs. Traditional continuum models are numerically insufficient to simulate the dynamic behavior of these complex systems, due to the rapid, orders-of-magnitude concentration shifts that occur. In this work, we present a novel framework for modeling the cell-level performance of pH-buffered aqueous electrolytes. We apply our model to conduct the first continuum-scale simulation of secondary ZABs with aqueous ZnCl2-NH4Cl electrolytes. We first use our model to interpret the results of two recent experimental studies of neutral ZABs, and show that the stability of the pH is a significant factor in cell performance. We then optimize the composition of the electrolyte and the design of the cell considering factors including pH stability, final discharge product and overall energy density. Our simulations predict that the effectiveness of the pH buffer is limited by slow mass transport and that chlorine-containing solids may precipitate in addition to ZnO.
      PubDate: 2017-09-12T05:21:19.927613-05:
      DOI: 10.1002/cssc.201701468
       
  • Enhanced Trace CO2 Capture on Heteroatom-substituted RHO zeolites under
           Humid Conditions
    • Authors: Quan-li Ke; Tian-jun Sun, Xiao-li Wei, Ya Guo, Shu-Dong Wang
      Abstract: In this paper, boron and copper heteroatoms were successfully incorporated into the frameworks of high-silica RHO zeolite by adopting a bulky alkali metal-crown ether (AMCE) complex as the template. As a consequence, these heteroatom-doped zeolites show both larger micropore surface areas and volumes than those of their aluminosilicate analogue. Proton-type RHO zeolites were then applied for separation of CO2 / CH4 / N2 mixtures so as to weaken the electric field of these zeolites and then decrease the adsorption heat. The adsorption results show that a balance between working capacity and adsorption heat could be achieved harmoniously on these heteroatom-doped zeolites. The ideal adsorbed solution theory (IAST) predictions further demonstrate their high selectivities even for remarkably dilute sources of carbon dioxide. Finally, the heteroatom-substituted zeolites, especially the boron-substituted one, could be thermally regenerated rapidly at 150℃ after full hydration and could maintain high regenerability up to 30 cycles, which makes them potential candidates for trace CO2 removal under humid conditions.
      PubDate: 2017-09-12T04:20:31.025185-05:
      DOI: 10.1002/cssc.201701162
       
  • Catalytic upgrading of ethanol to n-butanol: A progress in catalyst
           development
    • Authors: Xianyuan Wu; Geqian Fang, Yuqin Tong, Dahao Jiang, Zhe Liang, Wenhua Leng, Liu Liu, Pengxiang Tu, Hongjing Wang, Jun Ni, Xiaonian Li
      Abstract: In view that n-butanol as fuel additive has more advantageous physico-chemical properties compared to ethanol, ethanol valorization to n-butanol via homogeneous or heterogeneous catalysis has received great attention over the last decades both in the scientific and industrial fields. This paper reviewed the recent progress in catalyst development for upgrading ethanol to n-butanol, which involves homogeneous catalysts such as Iridium and Ruthenium complexes catalysts and heterogeneous catalysts mainly including metal oxides, hydroxyapatite (HAP) and especially supported metal catalysts. The structure-performance relationship of catalysts and underlying reaction mechanism were critically examined. Future research directions on the catalyst design and improvement were also proposed.
      PubDate: 2017-09-12T03:21:19.653865-05:
      DOI: 10.1002/cssc.201701590
       
  • Single-Atom Catalysts of Precious Metals for Electrochemical Reactions
    • Authors: Jiwhan Kim; Hee-Eun Kim, Hyunjoo Lee
      Abstract: Single-atom catalysts (SACs), where the metal atom is dispersed on the support without forming nanoparticles, have been used for various heterogeneous reactions and most recently for electro-chemical reactions. In this mini-review, we introduce recent exam-ples of single-atom electrocatalysts used for the oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR), hydrogen evo-lution reaction (HER), formic acid oxidation reaction (FAOR), and methanol oxidation reaction (MOR). Many density functional theory (DFT) simulations have predicted that SACs may be effective for CO2 reduction towards methane or methanol production while sup-pressing H2 evolution, and those cases are introduced here as well. Single atoms, mainly Pt single atoms, have been deposited on TiN or TiC nanoparticles, defective graphene nanosheets, N-doped covalent triazine framework, graphitic carbon nitride, S-doped zeo-lite template carbon, and Sb-doped SnO2 surfaces. Scanning transmission electron microscopy, extended X-ray absorption fine structure measurement, and in-situ infrared spectroscopy have been used to detect the single-atom structure and confirm the ab-sence of nanoparticles. SACs have shown high mass activity, min-imizing the use of precious metal, and unique selectivity distinct from nanoparticle catalysts due to the absence of ensemble sites. Additional features that SACs should possess for effective elec-trochemical applications were also suggested.
      PubDate: 2017-09-11T22:21:26.837017-05:
      DOI: 10.1002/cssc.201701306
       
  • Decoupling the Effects of High Crystallinity and Surface Area on the
           Photocatalytic Overall Water Splitting over β-Ga2O3 Nanoparticles by
           Chemical Vapor Synthesis
    • Authors: Sasa Lukic; Jasper Menze, Philipp Weide, Wilma Busser, Markus Winterer, Martin Muhler
      Abstract: Chemical vapor synthesis (CVS) is a unique method to prepare well-defined photocatalyst materials with both large specific surface area and a high degree of crystallinity. The obtained β-Ga2O3 nanoparticles were optimized for photocatalysis by reductive photodeposition of the Rh/CrOx cocatalyst system. The influence of the degree of crystallinity and the specific surface area on photocatalytic aqueous methanol reforming and overall water splitting (OWS) was investigated by synthesizing β-Ga2O3 samples in the temperature range from 1000˚C to 1500˚C. With increasing temperature, the specific surface area and the microstrain were found to decrease, whereas the degree of crystallinity and the crystallite size increased. While the photocatalyst with the highest specific surface area showed the highest aqueous methanol reforming activity, the highest OWS activity was observed for the sample with an optimum ratio between high degree of crystallinity and specific surface area. Thus, it was possible to show that the facile aqueous methanol reforming and the demanding OWS have different requirements for high photocatalytic activity.
      PubDate: 2017-09-11T10:45:30.589035-05:
      DOI: 10.1002/cssc.201701309
       
  • In-Situ Formed Hierarchical Metal-Organic Flexible Cathode for High-Energy
           Sodium-Ion Batteries
    • Authors: Ying Huang; Chun Fang, Rui Zeng, Yaojun Liu, Wang Zhang, Yanjie Wang, Qingju Liu, Yunhui Huang
      Abstract: Metal-organic compounds are a family of electrode materials with structural diversity and excellent thermal stability for rechargeable batteries. Here, we fabricate a hierarchical nanocomposite with metal-organic cuprous tetracyanoquino- dimethane (CuTCNQ) in three-dimensional (3D) conductive carbon nanofibers (CNFs) network by in-situ growth, and evaluate it as flexible cathode for sodium-ion batteries (SIBs). CuTCNQ in such flexible composite electrode is able to exhibit a superhigh capacity of 252 mAh g-1 at 0.1 C and highly reversible stability for 1200 cycles within the voltage range of 2.5 - 4.1 V (vs. Na+/Na). A high specific energy of 762 Wh kg-1 is obtained with high average potential of 3.2 V (vs. Na+/Na). The in-situ formed electroactive metal-organic composites with tailored nanoarchitecture provide a promising alternative choice for high-performance cathode materials in sodium-ion batteries with high energy.
      PubDate: 2017-09-10T21:25:46.040595-05:
      DOI: 10.1002/cssc.201701484
       
  • Atom Transfer Radical Addition to Unactivated Alkenes Employing
           Heterogeneous Visible Light Photocatalysis
    • Authors: Liang-Liang Mao; Huan Cong
      Abstract: Heterogeneous visible light photocatalysis represents an important direction toward the development of sustainable organic synthesis. In this Communication, we report visible light-induced, heavy metal-free atom transfer radical addition to unactivated terminal olefins using the combination of heterogeneous titanium dioxide as photocatalyst and a hypervalent iodine(III) reagent as co-initiator. The reaction can be applied to a range of substrates with good functional group tolerance under very mild condition. In addition to a number of commonly used atom transfer reagents, the relatively challenging chloroform is also suitable.
      PubDate: 2017-09-09T00:35:24.207771-05:
      DOI: 10.1002/cssc.201701382
       
  • Homogeneous water oxidation by half-sandwich iridium(III)NHC complexes
           with pendant hydroxy and amino groups
    • Authors: Bani Mahanti; Greco González Miera, Elisa Martínez-Castro, Michele Bedin, Belén Martín-Matute, Sascha Ott, Anders Thapper
      Abstract: Herein we report three Ir(III)Cp* complexes with hydroxy- (1, 2) or amino- (3) functionalized N-heterocyclic carbene (NHC) ligands as catalysts for efficient water oxidation induced by addition of ceric ammonium nitrate (CAN). The pendant hydroxy- or amino- groups are very important for activity and the complexes with heteroatom-functionalized NHC ligands show up to 15 times higher rate of oxygen evolution in CAN-induced water oxidation compared to a reference Ir(III)Cp* complex without heteroatom functionalization (4). The presence of molecular high-valent Ir intermediates that are presumably involved in the rate-determining step for water oxidation is established by UV-vis spectroscopic and ESI mass spectrometric analyses during turnover conditions. The hydroxy-groups on the NHC ligands, as well as chloride ligands on the iridium center are proposed to structurally stabilize the high-valent species, and thereby improve the catalytic activity. The Ir(III) complex 1 with a hydroxy-functionalized NHC shows the highest catalytic activity with a TON of 2500 obtained in 3 h and with>90% yield relative to the amount of used oxidant.
      PubDate: 2017-09-08T07:41:07.108966-05:
      DOI: 10.1002/cssc.201701370
       
  • Effects of Self-Assembling Monolayer Modification of NiOx Nanoparticles
           Layer on the Performance of Inverted Perovskite Solar Cells and
           Application in High Power-Per-Weight Devices
    • Authors: Qin Wang; Chu-Chen Chueh, Ting Zhao, Morteza Eslamian, Wallace C.H. Choy, Alex K.-Y. Jen
      Abstract: Entirely low-temperature solution-processed (≤ 100 °C) planar p-i-n perovskite solar cells (PVSCs) offer great potential for commercialization of roll-to-roll fabricated photovoltaic devices. However, the stable inorganic hole transporting layer (HTL) in PVSCs is usually processed at high temperature (200 °C ~500 °C) which is far beyond the tolerant temperature (≤ 150 °C) of roll-to-roll fabrication. In this context, inorganic NiOx -nanoparticles (NPs) are an excellent candidate to serve as the HTL in PVSCs, owing to their excellent solution-processability at room temperature. However, the low-temperature processing condition is usually accompanied with defect formation.To suppress this setback, we used a series of benzoic acid self-assembly monolayers (SAMs) to passivate the surface defects of the NiOx NPs, and found that 4-bromobenzoic acid could effectively play the role of the surface passivation. This SAM layer reduces the trap-assisted recombination, minimizes the energy offset between the NiOx NPs and perovskite, and changes the HTL surface wettability, thus enhances the perovskite crystallization, resulting in more stable PVSCs with enhanced power conversion efficiency (PCE) of 18.4%, exceeding the control device PCE (15.5%). Also, we incorporated the above-mentioned SAMs into flexible PVSCs (F-PVSCs) and achieved one of the highest PCE of 16.2% on polyethylene terephthalate (PET) substrate with a remarkable power-per-weight of 26.9 W/g.
      PubDate: 2017-09-07T13:20:49.326827-05:
      DOI: 10.1002/cssc.201701262
       
  • Rational Design of Sulfur-Doped Copper Catalysts for the Selective
           Electroreduction of Carbon Dioxide to Formate
    • Authors: Yun Huang; Yilin Deng, Albertus Denny Handoko, Gregory K L Goh, Boon Siang Yeo
      Abstract: The selective electroreduction of CO2 to formate (or formic acid) is currently of great interest in the field of renewable energy utilization. In this work, we designed a sulfur-doped Cu2O-derived Cu catalyst, and showed that the presence of sulfur could significantly tune the selectivity of Cu from producing a myriad of CO2 reduction products to almost exclusively formate. Sulfur is doped into the Cu catalysts by dipping the Cu substrates into ammonium polysulfide solutions. Catalyst films with the highest sulfur content of 2.7 atom% showed the largest formate current density (jHCOO-) of -13.9 mA/cm2 at -0.9 V vs. RHE, which is ~46 times larger than that previously reported on Cu(110) surfaces. At -0.8 V vs. RHE, the Faradaic efficiency of formate was maintained at ~75% for 12 h of continuous electrolysis. By analyzing how the jHCOO- and jH2 of the catalysts evolved with different sulfur content, we show that sulfur doping efficaciously increases formate production, while suppressing the hydrogen evolution reaction. Ag-S and Cu-Se catalysts did not exhibit any significant enhancement towards the reduction of CO2 to formate. This demonstrates clearly that sulfur and copper acted synergistically to promote the selective formation of formate. A hypothesis of the role of sulfur is proposed and discussed.
      PubDate: 2017-09-07T09:21:31.786827-05:
      DOI: 10.1002/cssc.201701314
       
  • Anatase-TiO2 as low-cost and sustainable buffering filler for nanosize
           Silicon anodes in Lithium-ion batteries
    • Authors: Fabio Maroni; Gilberto Carbonari, Fausto Croce, Roberto Tossici, Francesco Nobili
      Abstract: The design of effective supporting matrices to efficiently cycle Si nanoparticles is often difficult to be achieved and requires complex preparation strategies. In this work, we present a simple synthesis of low-cost and environmentally benign Anatase-TiO2 nanoparticles as buffering filler for Si nanoparticles (Si@TiO2). Average anatase crystallite size is estimated in 5 nm. A complete structural, morphological and electrochemical characterization is performed. Electrochemical test results show very good specific capacity values around up to 1000 mAhg-1 and cycling at several specific currents, ranging from 500 mAg-1 to 2000 mAg-1, demonstrating a very good tolerance to high cycling rates. Post-mortem morphological analysis shows very good electrode integrity after 100 cycles at 500 mAg-1 specific current.
      PubDate: 2017-09-07T08:20:45.708226-05:
      DOI: 10.1002/cssc.201701431
       
  • Ultrathin composite polymeric membranes for CO2/N2 separation with minimum
           thickness and high CO2 permeance
    • Authors: Benito Javier; Javier Sánchez Laínez, Beatriz Zornoza, Santiago Martín, Mariolino Carta, Richard Malpass-Evans, Carlos Téllez, Neil B. McKeown, Joaquín Coronas, Ignacio Gascon
      Abstract: The use of ultrathin films as selective layers in composite membranes offers significant advantages in gas separation for increasing productivity whilst reducing the membrane size and energy costs. In this contribution, composite membranes have been obtained by the successive deposition of ca. 1 nm thick monolayers of a polymer of intrinsic microporosity (PIM) on top of dense membranes of the ultra-permeable poly[1-(trimethylsilyl)-1-propyne] (PTMSP). The ultrathin PIM films (30 nm in thickness) demonstrate CO2 permeance up to 7 times higher than dense PIM membranes using only 0.04% of the mass of PIM without a significant decrease in CO2/N2 selectivity.
      PubDate: 2017-09-06T11:34:16.009573-05:
      DOI: 10.1002/cssc.201701139
       
  • Optimization of Photoanodes for Photocatalytic Water Oxidation by
           Combining a Heterogenized Iridium Water-Oxidation Catalyst with a
           High-Potential Porphyrin Photosensitizer
    • Authors: Kelly L. Materna; Jianbing Jiang, Kevin P. Regan, Charles A. Schmuttenmaer, Robert H. Crabtree, Gary Brudvig
      Abstract: Development of water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) has gained interest due to their ability to generate renewable fuels using solar energy. In this study, photoanodes were assembled composed of a SnO2 film sensitized with a combination of a high potentialCF3-substituted porphyrin dye with a THP-protectedhydroxamic acid surface-anchoring group, and a Cp*-iridium water-oxidation catalystcontaining a silatrane anchoring group. The dye-to-catalyst ratios were varied from 2:1 to 32:1 to optimize photocatalytic water oxidation. Photoelectrochemical measurements not only showed more stable and reproducible photocurrents for lower dye-to-catalyst ratios, but photostability was also improved. O2 production was confirmed in real-time over a 20-hour period using a Clark electrode. Photoanodes prepared from 2:1 and 8:1 dye-to-catalyst sensitization solutions provided the most active electrodes for photocatalytic water oxidation, performing approximately 30-35 turnovers in 20 hours.
      PubDate: 2017-09-06T09:52:21.350035-05:
      DOI: 10.1002/cssc.201701693
       
  • Quantum Chemical Modeling of Homogeneous Water Oxidation Catalysis
    • Authors: Rong-Zhen Liao; Per Siegbahn
      Abstract: The design of efficient and robust water oxidation catalysts has proven challenging in the development of artificial photosynthetic systems for solar energy harnessing and storage. Tremendous progress has been made in the development of homogeneous transition metal complexes capable of mediating water oxidation. To improve the efficiency of the catalyst and to design new catalysts, a detailed mechanistic understanding is necessary. Quantum chemical model calculations have been successfully used to complement the experimental techniques to suggest a catalytic mechanism and to identify all stationary points including transition states for both O-O bond formation and O2 release. In this review, we discuss the recent progress in the applications of the quantum chemical methods for the modeling of homogeneous water oxidation catalysis, covering various transition metals, including Mn, Fe, Co, Ni, Cu, Ru, and Ir.
      PubDate: 2017-09-05T21:26:44.970346-05:
      DOI: 10.1002/cssc.201701374
       
  • Diphenylpyridine Amine-Substituted Porphyrins as Hole-Transporting
           Materials for Perovskite Solar Cells
    • Authors: Un-Hak Lee; Randi Azmi, Septy Sinaga, Sunbin Hwang, Seung Hun Eom, Tae-Wook Kim, Sung Cheol Yoon, Sung-Yeon Jang, IN HWAN JUNG
      Abstract: The susceptibility of porphyrin derivatives to light-harvesting and charge-transport operations have enabled these materials to be employed in solar cell applications. The potential of porphyrin derivatives as hole-transporting materials (HTMs) for perovskite solar cells (PSCs) has recently been demonstrated, but research on the relationships between the porphyrin structure and device performance remains insufficient. In this work, a series of novel porphyrin derivatives, PZn-TPA-O, PZn-TPA, PZn-DPPA-O and PZn-DPPA, are developed and employed as HTMs for low-temperature processed PSCs. In our key design strategy, the electron deficient pyridine moiety was incorporated to down-shift HOMO levels of porphyrin HTMs. The porphyrin HTMs containing diphenylpyridine amine (DPPA) possess HOMO levels which are in good agreement with the perovskite active layers, thus facilitating hole transfers from the perovskite to the HTMs. The DPPA-containing PZn-DPPA based PSCs showed the best performance, with efficiency levels comparable to those of PSCs using spiro-OMeTAD, a current state-of-the-art HTM. In particular, PZn-DPPA based PSCs show superior air-stability in both doped and undoped forms, compared to spiro-OMeTAD based devices.
      PubDate: 2017-09-05T21:26:40.681091-05:
      DOI: 10.1002/cssc.201701526
       
  • Selective and Efficient Iridium Catalyst for the Reductive Amination of
           Levulinic Acid into Pyrrolidones
    • Authors: Shengdong Wang; Haiyun Huang, Christian Bruneau, Cedric Fischmeister
      Abstract: The catalytic reductive amination of Levulinic acid (LA) into pyrrolidones with iridium catalyst using H2 as hydrogen source is reported. The chemoselective iridium catalyst displayed high efficiency for the synthesis of a variety of N-substituted 5-methyl-2-pyrrolidones and N-arylisoindolinones. N-Substituted 5-methyl-2-pyrrolidone was evaluated as a bio-sourced substitute solvent to NMP (N-Methyl-pyrrolidone) in the catalytic arylation of 2-phenylpyridine.
      PubDate: 2017-09-05T12:20:37.784519-05:
      DOI: 10.1002/cssc.201701299
       
  • Co9S8/Co as a High Performance Anode for Sodium Ion Batteries with a
           Preferred Ether-based Electrolyte
    • Authors: Yingying Zhao; Qiang Pang, Yingjin Wei, Luyao Wei, Yanming Ju, Bo Zou, Yu Gao, Gang Chen
      Abstract: Co9S8 has been regarded as a desirable anode material for sodium ion batteries because of its high theoretical capacity. In this study, a Co9S8 anode material containing 5.5 wt% Co (Co9S8/Co) was prepared by a solid-state reaction. The material's electrochemical properties were studied with carbonate-based and ether-based electrolytes (the latter, EBE), which showed that the material had a longer cycling life and better rate capability in the EBE. This excellent electrochemical performance was attributed to the low apparent activation energy and the low over-potential for Na deposition in the ether based electrolyte, which improved the electrode kinetic properties. Also, EBE suppressed side reactions of the electrode and electrolyte, which avoided the formation of a solid electrolyte interphase film.
      PubDate: 2017-09-05T07:24:27.258399-05:
      DOI: 10.1002/cssc.201701334
       
  • Biocatalytic valorization of Furans: Opportunities for inherently unstable
           substrates.
    • Authors: Pablo Dominguez de Maria; Nadia V. Guajardo
      Abstract: Biogenic furans (Furfural and 5-hydroxymethylfurfural) are expected to become relevant building blocks based on their high functionalization and versatility. However, the inherent instability of furans poses considerable challenges for their synthetic modifications. Valorization routes of furans typically generate by-products, impurities, wastes, and a cumbersome downstream processing, compromising their ecological footprint. Biocatalysis may become an alternative, given the high selectivity of enzymes, together with the mild reaction conditions applied. This review critically discusses the options for enzymes in the upgrading of furans. Based on the reported literature, there is a variety of biocatalytic transformations applied to furans, with successful cases both in aqueous and in water-free media. Options comprise the biodetoxification of toxic furans in hydrolysates, selective syntheses based on oxidation-reduction processes, solvent-free esterifications, or carboligations to afford C12 derivatives. Reported strategies show in general promising but still modest productivities (range of 2-30 g product L-1 d-1, depending on the example). There are opportunities with high potential, deserving further development, scale-up and techno-economic assessment, to entirely validate them as realistic alternatives.
      PubDate: 2017-09-04T12:15:32.060844-05:
      DOI: 10.1002/cssc.201701583
       
  • Electrocatalytic water oxidation by MnOx@C: in-situ catalyst formation,
           carbon substrate variations and direct O2 / CO2 monitoring by
           membrane-inlet mass-spectrometry
    • Authors: Jens Melder; Wai Ling Kwong, Dimitriy Shevela, Johannes Messinger, Philipp Kurz
      Abstract: Layers of amorphous manganese oxides were directly formed on the surfaces of different carbon materials by exposing the carbon to aqueous solutions of permanganate (MnO4-) followed by sintering at 100 - 400°C. During electrochemical measurements in neutral aqueous buffer, nearly all of the Mn-oxide@Carbon electrodes show significant oxidation currents at potentials relevant for the oxygen-evolution reaction (OER). However, by combining electrolysis with product detection using mass-spectrometry, it was found that these currents were only strictly linked to water-oxidation where MnOx was deposited on graphitic carbon materials (faradaic O2 yields>90%). On the contrary, supports containing sp³-C's were found to be unsuitable as the OER is accompanied by carbon corrosion to CO2. Thus, choosing the "right" carbon material is crucial for the preparation of stable and efficient MnOx@C-anodes for water-oxidation catalysis. For MnOx on graphitic substrates, current densities of>1mA·cm-2 at η = 540 mV could be maintained for at least 16 h of continuous operation at pH 7 (very good values for electrodes containing only abundant elements like C, O and Mn) and post-operando measurements proved the integrity of both the catalyst coating and the underlying carbon at OER conditions.
      PubDate: 2017-09-04T10:15:32.275611-05:
      DOI: 10.1002/cssc.201701383
       
  • Anodic dissolution of Al current collectors in unconventional solvents for
           high voltage electrochemical double layer capacitors
    • Authors: Jakob Krummacher; Lars Henning Hess, Andrea Balducci
      Abstract: This study investigated the anodic dissolution of Al current collectors in unconventional electrolytes for high voltage electrochemical double layer capacitors (EDLC) containing adiponitrile (ADN), 3-cyanopropionic acid methyl ester (CPAME), 2-methyl-glutaronitrile (2-MGN) as solvent, and tetraethylammonium tetrafluroroborate (Et4NBF4) and tetraethylammonium bis(trifluoromethanesulfonyl)imide (Et4NTFSI) as conductive salts. In order to have a comparison with the state-of-the-art electrolytes, the same salts were also used in combination with acetonitrile (ACN). The chemical-physical properties of the electrolytes were investigated. Furthermore, their impact on the anodic dissolution of Al was analysed in detail, as well as the influence of this process on the performance of high voltage EDLCs. The results of this study indicated that in the case of Et4NBF4-based electrolytes the use of alternative solvent is very beneficial for the realization of stable devices. When Et4NTFSI is used, the reduced solubility of the complex Al(TFSI)3 appears to be the key for the realization of advanced electrolytes.
      PubDate: 2017-09-04T05:18:54.101189-05:
      DOI: 10.1002/cssc.201701422
       
  • High photoluminescence quantum yield in organic semiconductor-perovskite
           composite thin films
    • Authors: Giulia Longo; Maria-Grazia La-Placa, Michele Sessolo, Henk J. bolink
      Abstract: One of the obstacles to allow efficient radiative recombination in hybrid perovskites is their low exciton binding energy, typically in the orders of tens of meV. It has been shown that the use of electron-donor additives can lead to a substantial reduction of the non-radiative recombination in perovskite films. We expand this approach to the use of small molecules with semiconducting properties, which are candidate to be implemented in future optoelectronic devices. In particular, we have developed highly luminescent perovskite/organic semiconductors composite thin films, which can be processed from solution in a simple coating step. By tuning the relative concentration of MAPbBr3 and SPPO1, we showed that it is possible to achieve PLQY as high as 85%, thanks to dual function of SPPO1, which limit the grain growth while passivating the perovskite surface. The electroluminescence of these materials was investigated by fabricating multilayer LEDs, where the charge injection and transport was found to be severely hindered in the presence of solely the perovskite and SPPO1. This was alleviated by partially substituting the SPPO1 with a hole transporting material, mCP, leading to bright electroluminescence. This work shows the potential of combining perovskite and organic semiconductors in order to achieve materials with improved properties, and open new venues for the preparation of simple light-emitting devices using perovskites as the emitter.
      PubDate: 2017-09-04T04:15:23.443926-05:
      DOI: 10.1002/cssc.201701265
       
  • Cascade Reductive-Etherification of Bio-derived Aldehydes over Zr-based
           Catalysts
    • Authors: Suhas Shinde; Chandrashekhar V. Rode
      Abstract: A single pot, efficient catalytic cascade sequence is developed for the production of value-added ethers from bio-derived aldehydes. Etherification of 5-(hydroxymethyl)furfural with different aliphatic alcohols over acidic Zr-Montmorillonite (Zr-Mont) catalyst, produced a mixture of 5-(alkoxymethyl)furfural and 2-(dialkoxymethyl)-5-(alkoxymethyl)furan. The later was selectively converted back to 5-(alkoxymethyl)furfural by treating it with water over the same catalyst. Synthesis of 2,5-bis(alkoxymethyl)furan was successfully achieved through a cascade sequence involving etherification, transfer hydrogenation and re-etherification over a combination of acidic catalyst (Zr-Mont) and CTH catalyst [ZrO(OH)2]. This catalyst combination was further successfully explored for cascade conversion of 2-furfuraldehyde into 2-(alkoxymethyl)furan. The scope of this strategy was then extended for reductive-etherification of lignin derived arylaldehydes to get respective benzyl ethers in> 80% yield. Additionally, the mixture of Zr-Mont and ZrO(OH)2 doesn't undergo mutual destruction which was proved by recycle experiments and XRD analysis. Both the catalysts were thoroughly characterized using BET, NH3-TPD, CO2-TPD, pyridine-FTIR, XRD, XPS and ICP-OES techniques.
      PubDate: 2017-09-04T03:25:47.202509-05:
      DOI: 10.1002/cssc.201701275
       
  • Conducting Polymers Crosslinked with Sulfur as Cathode Materials for
           High-Rate, Ultralong-Life Lithium–Sulfur Batteries
    • Authors: Shuaibo Zeng; Ligui Li, Lihong Xie, Dengke Zhao, Nan Wang, Shaowei Chen
      Abstract: The Inside Cover picture shows the chemical immobilization of sulfur onto conducting polymers with thiol groups through inverse vulcanization, which significantly enhances both the rate performance and cycling stability of polymer cathodes in the green and sustainable lithium–sulfur batteries. More details can be found in the Full Paper by Zeng et al. (
      DOI : 10.1002/cssc.201700913).
      PubDate: 2017-09-04T02:50:31.367477-05:
       
  • Iron-Doped BaMnO3 for Hybrid Water Splitting and Syngas Generation
    • Authors: Vasudev Pralhad Haribal; Feng He, Amit Mishra, Fanxing Li
      Abstract: The Back Cover picture shows the exceptional syngas yield and watersplitting conversion obtained using iron-doped BaMnO3 redox catalyst in a hybrid solar-redox scheme. Density functional theory and thermodynamic calculations predict that BaMn0.5Fe0.5O3−δ be suitable for the reaction scheme. Experimental studies demonstrated 90% steam-to-hydrogen conversion during water splitting and over 90% syngas yield in the methane partial-oxidation step. The redox catalyst can be used to efficiently produce liquid fuel and hydrogen. More details can be found in the Full Paper by Haribal et al. (
      DOI : 10.1002/cssc.201700699).
      PubDate: 2017-09-04T02:50:25.811163-05:
       
  • Ionic-Liquid-Assisted Microwave Synthesis of Solid Solutions of
           Sr1−xBaxSnO3 Perovskite for Photocatalytic Applications
    • Authors: Tarek Alammar; Igor I. Slowing, Jim Anderegg, Anja-Verena Mudring
      Abstract: The Inside Back Cover picture shows the different perovskite structures obtained by microwave synthesis in ionic liquids, depending on the Sr/Ba content. More details can be found in the Full Paper by Alammar et al. (
      DOI : 10.1002/cssc.201700615).
      PubDate: 2017-09-04T02:50:19.672992-05:
       
  • Hybrid Deep Eutectic Solvents with Flexible Hydrogen-Bonded Supramolecular
           Networks for Highly Efficient Uptake of NH3
    • Authors: Yuhui Li; Mohammad Chand Ali, Qiwei Yang, Zhiguo Zhang, Zongbi Bao, Baogen Su, Huabin Xing, Qilong Ren
      Abstract: Invited for this month′s cover is the group of Qiwei Yang at the Zhejiang University. The image shows the effective capture of NH3 molecules by hybrid deep eutectic solvents comprising choline chloride, resorcinol, and glycerol. The Full Paper itself is available at 10.1002/cssc.201701135.“NH3 is the main alkaline gaseous pollutant in the atmosphere…” This and more about the story behind the research that inspired the Cover image is presented in the Cover Profile. Read the full text of the corresponding research at 10.1002/cssc.201701135. View the Front Cover here: 10.1002/cssc.201701616.
      PubDate: 2017-09-04T02:45:33.320334-05:
      DOI: 10.1002/cssc.201701617
       
  • Hybrid Deep Eutectic Solvents with Flexible Hydrogen-Bonded Supramolecular
           Networks for Highly Efficient Uptake of NH3
    • Authors: Yuhui Li; Mohammad Chand Ali, Qiwei Yang, Zhiguo Zhang, Zongbi Bao, Baogen Su, Huabin Xing, Qilong Ren
      Abstract: The Cover picture shows a representation of highly efficient capture of NH3 molecules by hybrid deep eutectic solvents that consist of three inexpensive components. These solvents were designed to have a flexible supramolecular network along with abundant hydrogen-bonding interaction sites, which enabled a strong physical solvation of NH3 molecules and realized solvent-unbreaking absorption. Both exceptional NH3 mass capacity and excellent desorption–regeneration performance were achieved, along with outstanding NH3/CO2 selectivity and environmental merits. More details can be found in the Full Paper by Li et al. (
      DOI : 10.1002/cssc.201701135).
      PubDate: 2017-09-04T02:45:20.580594-05:
       
  • Effect of FA/Cs Substitution and PbI2 on the Long Term Stability of Triple
           Cation Perovskites
    • Authors: Shashwat Shukla; Sudhanshu Shukla, Lew Jia Haur, Harsha Satya Sai, Guifang Han, Anish Priyadarshi, Tom Baikie, Subodh Mhaisalkar, Nripan Mathews
      Abstract: Altering cation and anion ratios in perovskites has been an excellent avenue in tuning the perovskite properties and enhancing the performance. Recently, MA/FA/Cs triple cation mixed halide perovskites have demonstrated efficiencies reaching up to 22 %. Similar to the widely explored MAPbI3, excess PbI2 is added in these perovskite films to enhance the performance. Previous reports demonstrate that the excess PbI2 is beneficial for the performance. However, not much work has been conducted about its impact on stability. Triple cation perovskites (TCP) deploy excess PbI2 up to 8 %. Thus, it is imperative to analyze the role of excess PbI2 in the degradation kinetics. In this paper, we have varied the amount of PbI2 in the triple cation perovskite films and monitored the degradation kinetics by X-ray diffraction (XRD) and optical absorption spectroscopy. We found that the inclusion of excess PbI2 adversely affects the stability of the material. Faster degradation kinetics is observed for higher PbI2 samples. However, excess PbI2 samples showed superior properties such as enhanced grain sizes and better optical absorption. Thus, careful management of the PbI2 quantity is required to obtain better stability and alternative pathways should be explored to achieve better device performance rather than adding excess PbI2.
      PubDate: 2017-09-03T21:31:24.45687-05:0
      DOI: 10.1002/cssc.201701203
       
  • Modulating Crystallinity of Graphitic Carbon Nitride for Photocatalytic
           Oxidation of Alcohols
    • Authors: Min Zhou; Pengju Yang, Rusheng Yuan, Abdullah M. Asiri, Muhammad Wakeel, Xinchen Wang
      Abstract: Exploiting efficient photocatalysts with strengthened structure properties for solar-driven alcohol oxidation is of great significance. Herein, we found that the photocatalytic performance of graphitic carbon nitrides can be sharply promoted by modulating the crystallinity. Results confirmed that the high crystallinity accelerates the separation and transfer of photogenerated charge carriers, thus providing more free-charges for photoredox reactions. More importantly, the crystallinity facilitated the adsorption of benzyl alcohol and desorption of benzyl aldehyde, and simultaneously lowered the energy barrier for O2 activation. As a result, the crystalline carbon nitride exhibited ~ 12-fold promotion with respect to the normal carbon nitride. The remarkable enhancement of activity can be attributed to the synergistic effects of the increased electron/hole separation and boosted surface reaction kinetic. These findings will open up new opportunities in modulating the structure of the polymers for a wide variety of organic transformations.
      PubDate: 2017-09-03T21:20:37.848231-05:
      DOI: 10.1002/cssc.201701392
       
  • Evident Improvement of Electrochemical Water Oxidation by Fine Tuning the
           Structure of Tetradentate N4 Ligands of Molecular Copper Catalysts
    • Authors: Junyu Shen; Mei Wang, Jinsuo Gao, Hongxian Han, Hong Liu, Licheng Sun
      Abstract: Two copper complexes, [L1Cu(OH2)](BF4)2 [1, L1 = N,N′-dimethyl-N,N′-bis(pyridin-2-ylmethyl)-1,2-diaminoethane] and [L2Cu(OH2)](BF4)2 [2, L2 = 2,7-bis(2-pyridyl)-3,6-diaza-2,6-octadiene], were prepared as molecular water oxidation catalysts. Complex 1 displayed an overpotential (η) of 1.07 V at 1 mA cm−2 and an observed rate constant (kobs) of 13.5 s−1 at η 1.0 V in pH 9.0 phosphate buffer solution, while 2 exhibited a significantly smaller η (0.70 V) to reach 1 mA cm−2 and a higher kobs (50.4 s−1) than 1 under identical test conditions. Additionally, 2 displayed a better stability than 1 in controlled potential electrolysis experiments in a Faradaic efficiency of 94% for O2 evolution at 1.58 V, when a casing tube was used for Pt cathode. The possible mechanism for 1- and 2-catalyzed O2 evolution reactions is discussed based on the experimental evidence. These comparative results indicate that fine tuning structures of tetradentate N4 ligands can bring about significant change in the performance of copper complexes for electrochemical water oxidation.
      PubDate: 2017-09-03T21:20:22.614833-05:
      DOI: 10.1002/cssc.201701458
       
  • Aqueous and Template-Free Synthesis of Meso-Macroporous Polymers for
           Highly Selective Capture and Conversion of CO2
    • Authors: Kuan Huang; Fujian Liu, Lilong Jiang, Sheng Dai
      Abstract: Meso-macroporous polymers possessing nitrogen functionality were innovatively synthesized via an aqueous and template-free route in this work. Specifically, the polymerization of 1-(4-vinylbenzyl)-1,3,5,7-tetraazaadamantan-1-ium chloride in aqueous solutions under high temperatures induces the decomposition of hexamethylenetetramine unit into ammonia and formaldehyde molecules, followed by the cross-linking of benzene rings via "resol chemistry". During this process, extended meso-macroporous frameworks were constructed, and meanwhile active nitrogen species were incoporated. Taking the advantage of meso-macroporosity and nitrogen functionality, the synthesized polymers offer competitive CO2 capacities (0.37−1.58 mmol/g at 0˚C and 0.15 bar) and extraodinary CO2/N2 selectivities (155−324 at 0 ˚C). Furthermore, after complexed with metal ions, the synthesized polymers show excellent activity for catalyzing the cycloaddition of propylene oxide with CO2 (Yield>98.5%, TOF: 612.9−761.1 h-1)
      PubDate: 2017-09-01T23:25:45.676774-05:
      DOI: 10.1002/cssc.201701666
       
  • Visible-light Homogeneous Photocatalytic Conversion of CO2 to CO in
           Aqueous Solutions with an Fe Catalyst
    • Authors: Marc Robert; Heng Rao, Julien Bonin
      Abstract: We used an iron substituted tetraphenyl porphyrin bearing positively charged trimethylammonio groups at the para position of each phenyl ring for the photoinduced conversion of CO2. This complex is water soluble and acts as a molecular catalyst to selectively reduce CO2 into CO under visible light irradiation in aqueous solutions (acetonitrile:water 1:9 v:v) with the assistance of purpurin, a simple organic photosensitizer. CO is produced with a catalytic selectivity of 95% and turnover up to 120, illustrating the possibility of photo-catalysing the reduction of CO2 in aqueous solution using visible light, a simple organic sensitizer coupled to an amine as sacrificial electron donor and an earth abundant metal based molecular catalyst.
      PubDate: 2017-09-01T07:20:22.966433-05:
      DOI: 10.1002/cssc.201701467
       
  • Al2O3 Underlayer Prepared by Atomic Layer Deposition for Efficient
           Perovskite Solar Cells
    • Authors: Jinbao Zhang; Adam Hultqvist, Tian Zhang, Liangcong Jiang, Changqing Ruan, Li Yang, Yibing Cheng, Marika Edoff, Erik Johansson
      Abstract: Perovskite solar cells, as a newly emerged solar energy conversion technology, have attracted tremendous attention in the solar cell community by demonstrating impressive enhancement in power conversion efficiencies. However, the high temperature and manually processed TiO2 underlayer prepared by spray pyrolysis has significantly limited the large-scale application and device reproducibility of the perovskite solar cells. Here, we for the first time utilize low-temperature atomic layer deposition (ALD) to prepare a compact Al2O3 underlayer for perovskite solar cells. The thickness of the Al2O3 layer can be controlled well by adjusting the deposition cycles during the ALD process. An optimal Al2O3 layer can effectively block the electron recombination at the perovskite/FTO interface as well as sufficiently transport the electrons via tunneling. Perovskite solar cells fabricated with an Al2O3 layer demonstrated the highest efficiency of 16.2% for 50 cycles of ALD (~5 nm), which is a significant improvement over the underlayer free PSCs which have an efficiency of 11.0%. Detailed characterization confirms that the thickness of the Al2O3 underlayer significantly influences the charge transfer resistance and electron recombination process in the devices. Furthermore, this work successfully shows the feasibility of using a high-bandgap semiconductor like Al2O3 as the underlayer in perovskite solar cells and opens up pathways to use ALD Al2O3 underlayers for flexible solar cells.
      PubDate: 2017-08-31T03:21:30.971583-05:
      DOI: 10.1002/cssc.201701160
       
  • Green solvent system for fabricating bismuth based lead-free
           (CH3NH3)3Bi2I9 perovskite photovoltaics with open circuit voltage over 0.8
           V
    • Authors: Congcong Wu; Haijin Li
      Abstract: The toxicity of lead present in organohalide perovskites and the hazardous solvent system used for their synthesis hinders the deployment of perovskite solar cells (PSCs). Here, we report an environmentally friendly route for synthesis of bismuth based lead-free (CH3NH3)3Bi2I9 perovskites that utilize ethanol as the solvent. Using this method, dense and homogeneous microstructure was obtained, compared the porous rough microstructure obtained by DMF solution. Thus, the photovoltaic performance was enhanced and open voltage as high as 0.84 V can be obtained.
      PubDate: 2017-08-30T14:20:21.933519-05:
      DOI: 10.1002/cssc.201701470
       
  • Three-dimensional Porous Nickel-Cobalt Nitrides Supported on Ni Foam as
           Efficient Electrocatalysts for Overall Water Splitting
    • Authors: Jintao Zhang; Yueqing Wang, Baohua Zhang, Wei Pan, Houyi Ma
      Abstract: Exploring highly efficient and durable bifunctional electrocatalyst from the earth-abundant low-cost transition metals is central to obtain clean hydrogen energy via the large scale electrolytic water splitting. Herein, we demonstrate in-situ synthesis of porous nickel-cobalt nitride nanosheets on macroporous Ni foam (NF) via a facile electro-deposition process followed by one-step annealing process in NH3 atmosphere. The transformation from metal hydroxide to metal nitride could efficiently enhance the electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Interestingly, we found that the incorporation of nickel could further boost the catalytic activity of cobalt nitride. Typically, when used as bifunctional electrocatalysts, the obtained nickel-cobalt nitride electrocatalyst shows superior catalytic performance toward both HER and OER with a low overpotential of 0.29 and 0.18 V to achieve a current density of 10 mA cm-2, respectively and good stabilities. The good electrocatalytic performance was also evidenced by the as-fabricated electrolyzer for overall water splitting, exhibiting a high gas generation rate for hydrogen and oxygen with the excellent stability in the prolonged alkaline water electrolysis. The present work provides an efficient approach to preparing 3D interconnected porous nickel-cobalt nitride network with exposed inner active sites for overall water splitting.
      PubDate: 2017-08-30T10:20:27.826612-05:
      DOI: 10.1002/cssc.201701456
       
  • Cobalt-Doping to Boost the Electrochemical Properties of Ni@Ni3S2 Nanowire
           Films for High-Performance Supercapacitors
    • Authors: Shusheng Xu; Tao Wang, Yujie Ma, Wenkai Jiang, Shuai Wang, Min Hong, Nantao Hu, Yanjie Su, Yafei Zhang, Zhi Yang
      Abstract: Metal sulfides have aroused great interest for energy storage. However, low specific capacity and inferior rate capability hinder their practical applications. In this work, we demonstrate a facile cobalt-doped (Co-doped) process to boost the electrochemical performance of Ni@Ni3S2 core−sheath nanowire film electrodes for high-performance electrochemical energy storage. Co ions are successfully and uniformly doped to Ni3S2 nanosheets by a facile ion exchange process. The electrochemical properties of film electrodes are greatly improved with ultrahigh volumetric capacity (increased from 105 to 730 C cm-3 at 0.25 A cm-3) and excellent rate capability after Co is doped to Ni@Ni3S2 core−sheath nanowires. A hybrid asymmetric supercapacitor using Co-doped Ni@Ni3S2 as positive electrode and graphene-carbon nanotubes as negative electrode is assembled which exhibits a ultrahigh volumetric capacitance of 142 F cm-3 (based on the total volume of both electrodes) at 0.5 A cm-3 and excellent cycle stability (only 3% capacitance decrease after 5000 cycles). Moreover, the volumetric energy density can reach up to 44.5 mWh cm-3, this value is much larger than those of as-reported thin film lithium batteries (1−10 mWh cm-3). These results revealed in our work may give an insight into high-performance film electrodes fabrication for energy storage applications
      PubDate: 2017-08-30T07:21:21.554582-05:
      DOI: 10.1002/cssc.201701305
       
  • Insight into aluminium sulfate catalyzed xylan conversion to furfural in
           γ-valerolactone/water biphasic solvent under microwave condition
    • Authors: Tao Yang; Yi-Han Zhou, Sheng-Zhen Zhu, Hui Pan, Yao-Bing Huang
      Abstract: A simple and efficient biphasic system with earth-abundant metal salt catalyst was reported to produce furfural from xylan with a high yield up to 87.8% under microwave condition. Strikingly, the metal salt Al2(SO4)3 exhibited excellent catalytic activity for xylan conversion due to its appropriate combination of Lewis and Brønsted acidity, and as well as a good phase separation promoter. The critical role of SO42- anion was firstly emphasized, which determined the aforementioned characteristic when combining with Al3+ cation. The solvents with γ-valerolactone (GVL) as organic phase provided the highest furfural yield, resulting from its good dielectric properties and dissolving capacity that facilitated the absorption of microwave energy and promoted mass transfer. Mechanistic studies suggested that the xylan-to-furfural conversion proceeded mainly via a hydrolysis-isomerization-dehydration pathway and the hexa-coordinated Lewis acidic [Al(OH)2(aq)]+ species were the active sites for xylose-xylulose isomerization. Detailed kinetic studies of the subreaction for xylan conversion revealed the regulatory role of GVL on the reaction rates and pathways, by promoting the rates of the key steps involved for furfural production and suppressed the side reactions for humin production. Finally, Al2(SO4)3 catalyst was successfully used for the production of furfural from several lignocellulosic feedstocks, revealing its great potential of being used for other biomass conversions.
      PubDate: 2017-08-30T03:20:33.569379-05:
      DOI: 10.1002/cssc.201701290
       
  • Design and Evaluation of a Boron Dipyrrin (BODIPY) Electrophore for Redox
           Flow Batteries
    • Authors: Niklas Heiland; Clemens Cidarér, Camilla Rohr, Piescheck Mathias, Johannes Ahrends, Martin Bröring, Uwe Schröder
      Abstract: A BODIPY (boron dipyrrin) dye was designed as a molecular single component electrophore in a redox flow battery. All positions at the BODIPY core were assessed from literature data, in particular from cyclic voltammetry and density functional calculations, and a minimum requirement substitution pattern accounting for solubility, aggregation, radical cation and anion stabilities, a large potential window, and synthetic accessibility was designed. In depths electrochemical and physical studies of this electrophore revealed suitable cathodic behavior and stability of the radical anion, but rapid anodic decomposition of the radical cation. Three products which formed under the conditions of controlled oxidative electrolysis were isolated and their structures determined by spectroscopy and comparison with a synthetic model compound. From these structures a benzylic radical reactivity, initiated by one-electron oxidation, was concluded to play the major role in this unexpected decomposition.
      PubDate: 2017-08-29T02:15:22.6456-05:00
      DOI: 10.1002/cssc.201701109
       
  • Facile Spray Pyrolysis Synthesis of Yolk-shell Earth-abundant Elemental
           NiFe-based Nanohybrid Electrocatalysts for Full Water Splitting
    • Authors: Zhenhai Wen; Hao Li, Suqin Ci, Mengtian Zhang, Junxiang Chen, Keyuan Lai
      Abstract: It is critical while remains a daunting challenge in the development of high-activity electrocatalysts for water splitting that comprise only inexpensive, earth-abundant elements. In this work, the preparation of yolk-shell Ni3Fe/Ni3FeN was developed by a possible scale-up method using spray pyrolysis technique. The yolk-shell Ni3Fe/Ni3FeN presents excellent catalytic activity for OER and HER with overpotentials of 268 mV and 166 mV at 10 mA cm-2, respectively, and bears a prominent electrochemical durability. The overall water splitting on the electrolyzer with yolk-shell Ni3Fe/Ni3FeN as cathode and anode only requires a cell voltage of 1.62 V to reach current density of 10 mA cm-2. The present research not only proposes a new route in synthesizing advanced functional electrocatalysts for overall water splitting but also shed light on its potential commercial application.
      PubDate: 2017-08-28T09:16:37.643301-05:
      DOI: 10.1002/cssc.201701521
       
  • Electrolyte engineering toward efficient water splitting at mild pH
    • Authors: Tatsuya Shinagawa; Marcus Tze-Kiat Ng, Kazuhiro Takanabe
      Abstract: The development of processes for the conversion of H2O/CO2 driven by electricity generated in renewable manners is essential to achieve sustainable energy and chemical cycles, in which the electrocatalytic oxygen evolution reaction (OER) is one of the bottlenecks. In this contribution, the influences of the electrolyte molarity and identity on OER at alkaline to neutral pH were investigated at an appreciable current density of ~10 mA cm−2, revealing (1) the clear boundary of reactant switching between H2O/OH− due to the diffusion limitation of OH− and (2) the substantial contribution of the mass transport of the buffered species in buffered mild pH conditions. These findings propose a strategy of electrolyte engineering: tuning the electrolyte properties to maximize the mass-transport flux. The concept was successfully demonstrated for OER as well as overall water electrolysis in buffered mild pH conditions, shedding light on the development of practical solar fuel production systems.
      PubDate: 2017-08-28T06:20:52.251692-05:
      DOI: 10.1002/cssc.201701266
       
  • Photocatalytic CO2-to-CO Conversion by a Copper(II) Quaterpyridine Complex
    • Authors: Marc Robert; Zhenguo Guo, Fei Yu, Ying Yang, Chi-Fai Leung, Siu-Mui Ng, Chiu-Chiu Ko, Claudio Cometto, Tai-Chu Lau
      Abstract: The invention of efficient systems for the photocatalytic reduction of CO2 comprising earth-abundant metal catalysts is a promising approach for the production of solar fuels. One bottleneck is to design highly selective and robust molecular complexes able to transform the gas. The Cu(II) quaterpyridine complex [Cu(qpy)]2+ (1) is found to be a highly efficient and selective catalyst for visible-light driven CO2 reduction in CH3CN using [Ru(bpy)3]2+ as photosensitizer, BIH/TEOA as sacrificial reductant. The photocatalytic reaction is greatly enhanced by the presence of H2O (1-4% v/v), and a TON of>12,400 for CO production can be achieved with 97% selectivity, which is among the highest of molecular 3d CO2 reduction catalysts. Results from Hg-poisoning and dynamic light scattering (DLS) experiments suggest that this photocatalysis is homogenous. To the best of our knowledge 1 is the first example of molecular Cu-based catalyst for the photoreduction of CO2.
      PubDate: 2017-08-25T04:39:30.374325-05:
      DOI: 10.1002/cssc.201701354
       
  • Benzoate Anions-Intercalated Layered Cobalt Hydroxide Nanoarray: An
           Efficient Electrocatalyst for Oxygen Evolution Reaction
    • Authors: Xuping Sun; Xiang Ren, Xuqiang Ji, Zhiang Liu, Gu Du, Abdullah M. Asiri, Xuping Sun, Liang Chen
      Abstract: Efficient oxygen evolution reaction (OER) catalysts are highly desired to improve the overall efficiency of electrochemical water splitting. In this communication, we develop a benzoate anions-intercalated layered cobalt hydroxide nanobelt array on nickel foam (benzoate-Co(OH)2/NF) via a one-pot hydrothermal process. As a three-dimensional electrode, benzoate-Co(OH)2/NF with an expanded interlayer spacing (14.72 Å) drives a high OER catalytic current density of 50 mA cm-2 at an overpotential of 291 mV, outperforming its carbonate anions-intercalated counterpart with a lower interlayer spacing of 8.81 Å (337 mV overpotential at 50 mA cm-2). Moreover, this benzoate-Co(OH)2/NF can maintain its catalytic activity for 21 h.
      PubDate: 2017-08-24T23:35:39.589067-05:
      DOI: 10.1002/cssc.201701358
       
  • Iron-Catalyzed C-O Bond Activation: Opportunity for Sustainable Catalysis
    • Authors: Elwira Bisz; Michal Szostak
      Abstract: Oxygen-based electrophiles have emerged as some of the most valuable cross-coupling partners in organic synthesis due to several major strategic and environmental benefits such as abundance and potential to avoid toxic halide waste. In this context, iron-catalyzed C-O activation/cross-coupling holds particular promise to achieve sustainable catalytic protocols due to its natural abundance, inherent low toxicity, an excellent economic and ecological profile. Recently, tremendous progress has been achieved in the development of new methods for functional group tolerant iron-catalyzed cross-coupling reactions by selective C-O cleavage. These methods establish highly attractive alternatives to traditional cross-coupling reactions using halides as electrophilic partners. In particular, new easily accessible oxygen-based electrophiles have emerged as substrates in iron-catalyzed cross- coupling reactions, which significantly broaden the scope of this catalysis platform. New mechanistic manifolds involving iron catalysis have been established, thus opening vistas for the development of a wide range of unprecedented reactions. The synthetic potential of this sustainable mode of reactivity has been highlighted by the development of new strategies in the construction of complex motifs, including in target synthesis. In this minireview, we discuss the most recent advances in sustainable iron-catalyzed cross-coupling of C-O based electrophiles with a focus on both mechanistic aspects and synthetic utility. It should be noted that this catalytic manifold provides access to motifs that are often not easily available by other methods, such as the assembly of stereodefined dienes or C(sp2)-C(sp3) cross-couplings, emphasizing the synthetic importance of this mode of reactivity.
      PubDate: 2017-08-24T21:35:33.270552-05:
      DOI: 10.1002/cssc.201701287
       
  • Dendritic Fibrous Nanosilica (DFNS) for Catalysis, Energy Harvesting, CO2
           Mitigation, Drug Delivery and Sensing
    • Authors: Ayan Maity; Vivek Polshettiwar
      Abstract: Morphology-controlled nanomaterials such as silica play a crucial role in the development of technologies for addressing challenges in the fields of energy, environment and health. After the discovery of Stöber silica, followed by the discovery of mesoporous silica materials, such as MCM-41 and SBA-15, a significant surge in the design and synthesis of nanosilica with various sizes, shapes, morphologies and textural properties (surface area, pore size and pore volume) has been observed in recent years. One notable invention is dendritic fibrous nanosilica (DFNS), also known as KCC-1. This material possesses a unique fibrous morphology, unlike the tubular porous structure of various conventional silica materials. It has a high surface area with improved accessibility to the internal surface, tunable pore size and pore volume, controllable particle size, and importantly, improved stability. After its discovery, a large number of reports appeared in the literature citing its successful use in a range of applications, such as catalysis, solar energy harvesting (photocatalysis, solar cells, etc.), energy storage, self-cleaning antireflective coatings, surface plasmon resonance (SPR)-based ultra-sensitive sensors, CO2 capture and biomedical applications (drug delivery, protein and gene delivery, bioimaging, photothermal ablation, and Ayurvedic and radiotherapeutics drug delivery, among others). These reports indicate that dendritic fibrous nanosilica has excellent potential as an alternative to popular silica materials such as MCM-41, SBA-15, Stöber silica, and mesoporous silica nanoparticles (MSNs), among others. This review provides a critical survey of the dendritic fibrous nanosilica family of materials, and the discussion includes i) the synthesis and formation mechanism, ii) applications in catalysis and photocatalysis, iii) applications in energy harvesting and storage, iv) applications in magnetic and composite materials, v) applications in CO2 mitigation, v) biomedical applications, and vi) analytical applications (sensing, extraction, and chromatography). Wherever possible, the comparison of dendritic fibrous nanosilica -based materials with conventional mesoporous materials, such as MCM-41, SBA-15, Stöber silica, and MSNs, is presented.
      PubDate: 2017-08-23T09:35:43.602932-05:
      DOI: 10.1002/cssc.201701076
       
  • The effect of the formulation of silicon-based composite anode on its
           mechanical, storage and electrochemical properties
    • Authors: Daniel Bélanger; BIRHANU DESALEGN ASSRESAHEGN
      Abstract: In this work, the effect of the formulation of silicon-based composite anode on its mechanical, storage and electrochemical properties was investigated. The formulation of the electrode was changed by using hydrogenated or modified (through covalent attachment of a binding additive eg. polyacrylic acid) silicon and acetylene black or graphene sheets, as conducting additive. We found that the composite anode with the covalently grafted binder has the highest elongation without break and strong adhesion to the current collector. It was also found that these mechanical properties are significantly dependent on the conductive carbon additive used and that the use of graphene sheets instead of acetylene black can significantly improve elongation and adhesion. Upon storage at ambient conditions during 180 days, the electronic conductivity and discharge capacity of the modified silicon electrode showed a much smaller decrease than the hydrogenated silicon composite electrode suggesting that the modification can play a passivation role to maintain a constant active material composition. Moreover, it was shown that this composite Si anode has high packing density and consequently thin film electrodes having a very high material loading can be prepared without penalizing its electrochemical performance.
      PubDate: 2017-08-23T09:35:28.281898-05:
      DOI: 10.1002/cssc.201701281
       
  • Electrocatalytic Conversion of CO2 and Nitrate Ions to Urea below -1.0 V
           vs Ag/AgCl by a TiO2-Nafion® Composite Electrode
    • Authors: Saravanakumar Duraisamy; Jieun Song, Sunhye Lee, Namhwi Hur, Woonsup Shin
      Abstract: CO2 and nitrate ions were successfully converted to urea by a TiO2/Nafion® nanocomposite electrode under ambient conditions. The composite electrode was constructed by drop-casting the mixture of P-25 titania and Nafion® solution on an ITO electrode. When the electrode was electrolyzed in CO2-saturated 0.1 M KNO3 (pH 4.5) solution at -0.98 V vs. Ag/AgCl, urea was formed with a Faradaic efficiency of 40%. The other reduced products obtained were ammonia, CO, and H2.
      PubDate: 2017-08-23T07:36:15.490408-05:
      DOI: 10.1002/cssc.201701448
       
  • Modulating excitonic recombination effects and improved PLQY through
           one-step synthesis of perovskite nanoparticles for LEDs
    • Authors: Sneha A. Kulkarni; Subas Muduli, Guichuan Xing, Natalia Yantara, Mingjie Li, Chen Shi, Tze Chien Sum, Nripan Mathews, Tim J. White, Subodh G. Mhaisalkar
      Abstract: The primary advantages of halide perovskites for light emitting diodes (LEDs) are solution processability, direct band gap, good charge carrier diffusion lengths, low trap density, and reasonable carrier mobility. The luminescence in three-dimensional (3D) halide perovskite thin films originates from free electron-hole bimolecular recombination. However, the slow bimolecular recombination rate is a fundamental performance limitation. Perovskite nanoparticles could result in improved performance but processability and cumbersome synthetic procedures remain challenges. Herein, these constraints are overcome by tailoring the 3D perovskite as a near monodisperse nanoparticle film laid down via a one step in-situ deposition method. Replacing methyl ammonium bromide (CH3NH3Br, MABr) partially by octyl ammonium bromide (CH3(CH2)7NH3Br, OABr) in defined mole ratios in the perovskite precursor proved crucial for the nanoparticle formation. Films consisting of the in-situ formed nanoparticles displayed signatures associated with excitonic recombination, rather than that of bimolecular recombination associated with 3D perovskites. This transition was accompanied by enhanced PLQY (~20.5% vs 3.40%). PeLEDs fabricated from the nanoparticle films exhibit a one order of magnitude improvement in current efficiency and a doubling in luminance efficiency. This study provides the means to control perovskite morphologies through the selection and mixing of appropriate additives.
      PubDate: 2017-08-23T05:30:45.825235-05:
      DOI: 10.1002/cssc.201701067
       
  • Electrolyte engineering for optimizing high-rate double-layer capacitances
           of micropore- and mesopore-rich activated carbon
    • Authors: Ting-Hao Chen; Cheng-Hsien Yang, Ching-Yuan Su, Tai-Chou Lee, Quan-Feng Dong, Jeng-Kuei Chang
      Abstract: Various types of electrolyte cation as well as binary cations are used to optimize the capacitive performance of activated carbon (AC) with different pore structures. The high-rate capability of micropore-rich AC, governed by the mobility of desolvated cations, can outperform that of mesopore-rich AC, which essentially depends on the electrolyte conductivity.
      PubDate: 2017-08-22T12:30:31.841807-05:
      DOI: 10.1002/cssc.201701476
       
  • Dry reforming of methane in a gliding arc plasmatron: Towards a better
           understanding of the plasma chemistry
    • Authors: Emelie Cleiren; Stijn Heijkers, Marleen Ramakers, Annemie Bogaerts
      Abstract: We studied the dry reforming of methane in a plasma reactor, called gliding arc plasmatron, for different CH4 fractions in the mixture. The CO2 and CH4 conversions reach their highest values of around 18 and 10 %, respectively, at 25 % CH4 in the gas mixture, corresponding to an overall energy cost of 10 kJ/L (or 2.5 eV/molec) and an energy efficiency of 66 %. CO and H2 are the major products, with some smaller fractions of C2Hx (x= 2, 4 or 6) compounds and H2O formed as well. We also present a chemical kinetics model, to investigate the underlying chemical processes. The calculated CO2 and CH4 conversion and the energy efficiency are in good agreement with the experimental data. The model calculations reveal that the reaction of CO2 (mainly in vibrationally excited levels) with H radicals is mainly responsible for the CO2 conversion, especially at higher CH4 fractions in the mixture, and this explains why the CO2 conversion rises upon rising CH4 fraction. The main process responsible for CH4 conversion is the reaction with OH radicals. The excellent energy efficiency can be explained by the non-equilibrium character of the plasma, where the electrons mainly activate the gas molecules, and by the important role of the vibrational kinetics of CO2. Our results demonstrate that a gliding arc plasmatron is very promising for dry reforming of methane.
      PubDate: 2017-08-22T09:30:26.650034-05:
      DOI: 10.1002/cssc.201701274
       
  • Polymeric Redox Active Electrodes for Sodium Ion Batteries
    • Authors: Naiara Fernández; Paula Sanchez-Fontecoba, Elizabeth Castillo-Martínez, Javier Carretero-González, Teófilo Rojo, Michel Armand
      Abstract: Polymer binding agents are critical for the good performance of the electrodes of sodium and lithium ion batteries during cycling as they hold the electroactive material together forming a cohesive assembly by means of mechanical and chemical stability as well as adhesion to the current collector. Herein, novel redox active polymer binders that insert Na+ ions and show adhesion properties were synthesized by adding polyetheramine blocks (Jeffamine®) based on mixed propylene oxide and ethylene oxide blocks to p-phenylenediamine and terephthalaldehyde units forming electroactive Schiff bases groups along the macromolecule. Synthesis parameters and the electrochemical properties of these terpolymers as sodium ion negative electrodes in half-cells have been studied. Reversible capacities of 300 mAh/g (50 wt. % conducting carbon) and 200 mAh/g (20 wt. % conducting carbon) are achieved, in powder and Cu supported electrodes, respectively for a polySchiff-polyether terpolymer synthesized using a poly(ethylene oxide) block of 600 g/mol, instead of one third of the aniline units. The new redox active polymers were also deployed as binding agent of another anode material (hard carbon), leading to an increase of the total capacity of the electrode compared to other standard fluorinated polymer binders such as polyvinylidene fluoride.
      PubDate: 2017-08-22T07:10:43.900294-05:
      DOI: 10.1002/cssc.201701471
       
  • A New Energy-Saving Catalytic System: CO2 Activation via Metal/Carbon
           Catalyst
    • Authors: Danim Yun; Dae Sung Park, Kyung Rok Lee, Yang Sik Yun, Tae Yong Kim, Hongseok Park, Hyunjoo Lee, Jongheop Yi
      Abstract: Conversion of carbon dioxide for producing useful chemicals is an attractive method to reduce greenhouse gas emissions and to produce sustainable chemicals. However, the thermodynamic stability of CO₂ necessitates high levels of energy consumption for its conversion to chemicals. Here, we suggest a new catalytic system with an alternative heating system allowing for minimal energy consumption during CO₂ conversion. In this system, electrical energy is transferred as heat energy to the metal supported on carbon catalyst. Fast ramping rates allow for high operating temperatures (Tapp=250 °C) to be reached within 5 minutes, leading to an 80-fold lowering of energy consumption in methane reforming using CO₂ (DRM). In addition, the consumed energy normalized by time during DRM reaction in current-assisted catalysis is 6-fold lower (11.0 kJ·min-1) than conventional heating systems (68.4 kJ·min-1).
      PubDate: 2017-08-21T22:06:50.122792-05:
      DOI: 10.1002/cssc.201701283
       
  • Angelica Lactones: from Biomass-Derived Platform Chemicals to Value-Added
           Products
    • Authors: Arlene Correa; Carolina G. S. Lima, Júlia Monteiro, Thiago Melo Lima, Marcio Webber Paixão
      Abstract: The upgrading of biomass-derived compounds has arisen in recent years as a very promising research field in both academia and industry. In this sense, a lot of new processes and products have been developed, often involving levulinic acid as a starting material or intermediate. In the last few years, though, other scaffolds have been receiving growing attention, in special, angelica lactones. Considering these facts and the emergent applications of said molecules, in this review we will discuss their preparation and applications - the use of these frameworks as starting materials in organic synthesis to produce potential bioactive compounds will be covered, as well as their arising use as the foundation to highly regarded compounds such as liquid alkanes with prospective use as fuels and polymers.
      PubDate: 2017-08-21T10:00:39.20312-05:0
      DOI: 10.1002/cssc.201701469
       
  • Wacker Oxidation of Terminal Alkenes Over ZrO2-Supported Pd Nanoparticles
           Under Acid- and Cocatalyst-Free Conditions
    • Authors: Zhenzhong Zhang; Yuhya Kumamoto, Taishin Hashiguchi, Tetsuya Mamba, Haruno Murayama, Eiji Yamamoto, Tamao Ishida, Tetsuo Honma, Makoto Tokunaga
      Abstract: Highly efficient Wacker oxidation of aromatic or aliphatic terminal alkenes into methyl ketones and benzofurans is developed by using reusable Pd0 nanoparticles (NPs) supported on ZrO2 under acid- and cocatalyst-free conditions. Molecular oxygen or air can be utilized as the terminal oxidant, which results in the formation of H2O as the only theoretical byproduct. The activation of the Pd NPs by O2 plays an important role in promoting this reaction. Interestingly, PdO supported on ZrO2 showed no activity. Additionally, the Pd particle size significantly affects the catalytic activity, with an apparent optimal diameter of 4–12 nm. In addition to the heterogeneous catalyst forms, the Pd NPs can be generated from a Pd0 complex during the reaction, and these particles are even recyclable.Terminal alkenes take a Wacker! ZrO2-supported Pd0 NPs with a diameter of 4–12 nm exhibited high catalytic activity for Wacker oxidation and Wacker-type cyclization of terminal alkenes into methyl ketones and benzofurans. The reactions are performed under acid- and cocatalyst-free conditions, and O2 is employed as the sole oxidant.
      PubDate: 2017-08-21T03:07:03.479665-05:
      DOI: 10.1002/cssc.201701016
       
  • Interfacial heterojunction engineering of ZnIn₂S₄/MoSe₂ hierarchical
           nanoarchitectures for highly efficient noble-metal-free photocatalytic
           hydrogen evolution under visible light
    • Authors: Deqian Zeng; Lang Xiao, Wee-Jun Ong, Pengyuan Wu, Hongfei Zheng, Yuanzhi Chen, Dong-Liang Peng
      Abstract: Exploiting a highly efficient visible-light-driven photocatalyst is an urgent necessity for photocatalytic hydrogen (H₂) generation from water splitting. Herein, flower-like ZnIn₂S₄ hierarchical architectures assembled by ultrathin nanosheets were synthesized by a facile one-pot polyol approach, and subsequently, the colloidally developed two-dimensional (2D) network-like MoSe₂ was successfully hybridized with ZnIn₂S₄ via a facile hybridization approach by taking advantage of their analogues intrinsic layered morphologies. The ZnIn₂S₄/MoSe₂ heterostructures show enhanced noble-metal-free photocatalytic H₂ evolution compared to pure ZnIn₂S₄. It is noteworthy that the optimum nanocomposite of ZnIn₂S₄/2%MoSe₂ photocatalyst displays a dramatically high H₂ generation rate of 2228 μmol g¯¹ h¯¹ and an apparent quantum yield (AQY) of 21.39% at 420 nm. This study presents an unprecedented ZnIn₂S₄/MoSe₂ metal-sulfide/metal-selenide hybrid system for remarkable H₂ evolution. Importantly, the present efficient hybridization strategy uncovers a huge potential in the construction of hierarchical nanoarchitectures for a multitude of energy storage and solar energy conversion applications.
      PubDate: 2017-08-18T07:00:33.267296-05:
      DOI: 10.1002/cssc.201701345
       
  • Synthesis of renewable lubricant alkanes from biomass-derived platform
           chemicals
    • Authors: Mengyuan Gu; Qineng Xia, Xiaohui Liu, Yong Guo, Yanqin Wang
      Abstract: Catalytic synthesis of liquid alkanes from renewable biomass has received tremendous attention in recent years. However, highly branched lubricant alkanes are not yet synthetically exploited from biomass and are currently produced by hydrocracking and hydroisomerization of long-chain n-paraffins. Here we describe a selective catalytic synthetic route for the production of highly branched C23 alkanes for lubricant base oil component from biomass-derived furfural and acetone, through a tandem four-step process, namely aldol condensation of furfural with acetone to produce a C13 double adduct, then selective hydrogenation to a C13 ketone, followed by a second condensation of the C13 ketone with furfural to generate a C23 aldol adduct and finally to highly branched C23 alkanes by hydrodeoxygenation. The overall yield of C23 alkanes reaches in 50.6% (97.9%×72.8%×83.8%×84.8%) from furfural. This work opens a general strategy for the synthesis of high-quality lubricant alkanes from renewable biomass.
      PubDate: 2017-08-18T05:00:23.410735-05:
      DOI: 10.1002/cssc.201701200
       
  • Nanoparticles embedded in amphiphilic membranes for CO2 separation and
           dehumidification
    • Authors: Wai Fen YONG; Yan Xun Ho, Tai-Shung Chung
      Abstract: Polymers containing ethylene oxide groups have gained significant interest as the ethylene oxide groups have favorable interactions with polar molecules such as H2O, quadrupolar molecules such as CO2 and metal ions. However, the main challenges of poly(ethylene oxide) (PEO) membranes are their weak mechanical properties and high crystallinity nature. The amphiphilic copolymer made from poly(ethylene oxide) terephthalate and poly(butylene terephthalate) (PEOT/PBT) comprising both hydrophilic and hydrophobic segments. The hydrophilic PEOT segment is thermosensitive that facilities gas transports while the hydrophobic PBT segment is rigid that provides mechanical robustness. This work demonstrates a novel strategy to design amphiphilic mixed matrix membranes (MMMs) by incorporating zeolitic imidazolate framework, ZIF-71, into the PEOT/PBT copolymer. The resultant membrane shows an enhanced CO2 permeability with an ideal CO2/N2 selectivity surpassing the original PEOT/PBT and Robeson's Upper bound line. The nanoparticles embedded amphiphilic membranes exhibit characteristics of high transparency and mechanical robustness. Mechanically strong composite hollow fiber membranes consisting PEOT/PBT/ZIF-71 as the selective layer have also been prepared. The resultant hollow fibers possess an excellent CO2 permeance of 131 GPU, CO2/N2 selectivity of 52.6, H2O permeance of 9,300 GPU and H2O/N2 selectivity of 3,700, showing great potential for industrial CO2 capture and dehumidification.
      PubDate: 2017-08-17T11:25:24.58133-05:0
      DOI: 10.1002/cssc.201701405
       
  • Continuous production of bio-renewable, polymer-grade lactone monomers
           through Sn-β catalysed Baeyer-Villiger oxidation with H2O2
    • Authors: Keiko Yakabi; Thibault Mathieux, Kirstie Milne, Eva M Lopez-Vidal, Antoine Buchard, Ceri Hammond
      Abstract: The Baeyer-Villiger oxidation is a key transformation for sustainable chemical synthesis, especially when H2O2 and solid materials are employed as oxidant and catalyst, respectively. We demonstrate that 4-substituted cycloketones, readily available from renewables, present excellent platforms for Baeyer-Villiger upgrading. Such substrates exhibit substantially higher levels of activity, and produce lactones at higher levels of lactone selectivity at all values of substrate conversion, relative to non-substituted cyclohexanone. For 4-isopropyl cyclohexanone, readily available from β-pinene, continuous upgrading was also evaluated in a plug flow reactor. Excellent selectivity (< 90 % at 65 % conversion), stability and productivity were observed over 56 h, with over 1000 turnovers (mol. product / mol. Sn) being achieved with no loss of activity. A maximum space-time yield almost twice that obtained for non-substituted cyclohexanone was also obtained for this substrate (1173 vs. 607 g (product) kg-1 (cat) cm-3 (reactor) h-1). The lactone produced is also shown to be of suitable quality for ring opening polymerisation. In addition to demonstrating the viability of the Sn-β/H2O2 system to produce renewable lactone monomers suitable for polymer applications, the substituted alkyl cyclohexanones studied in this work also allowed us to probe the steric, electronic and thermodynamic elements of this transformation in greater detail than previously achieved.
      PubDate: 2017-08-13T21:25:39.988384-05:
      DOI: 10.1002/cssc.201701298
       
  • Synthetic Manipulation of Hybrid Perovskite Systems in Search of Novel and
           Enhanced Functionalities
    • Authors: Rounak Naphade; Satyawan Nagane, Umesh Bansode, Mukta Tathavadekar, Aditya Sadhanala, Satishchandra B. Ogale
      Abstract: Over the past few years the organic/Inorganic hybrid perovskite systems have emerged as a promising class of materials for photo-voltaic and electroluminescent thin film device applications, in view of their unique set of tunable optoelectronic properties. Importantly, these materials can be easily solution-processed at low temperatures and as such are amenable to facile molecular engineering. Thus, a variety of low dimensional forms and quantum structures of these materials can be obtained through strategic synthetic manipulations via small molecule incorporation or molecular ion doping. In this mini review, we specifically focus on these approaches and outline the possibilities of utilizing these for enhanced functionalities and newer application domains.
      PubDate: 2017-08-13T21:25:26.044652-05:
      DOI: 10.1002/cssc.201701093
       
  • Self-Co-Catalyzed Fluorine-Doped Hematite Nanocrystal for Efficient Water
           Oxidation
    • Authors: Yi Xie; Junfeng Xie, Weiwei Liu, Jianping Xin, Fengcai Lei, Li Gao, Haichao Qu, Xiaodong Zhang
      Abstract: Herein, enhanced light absorption and oxygen-evolving activity were simultaneously achieved by doping fluorine anions into hematite nanocrystals. With the merits of anion doping, the band structure of hematite can be effectively regulated, leading to the generation of defect level between the bandgap and remarkably increased visible light absorption. In addition, the activity for electrocatalytic oxygen evolution reaction (OER) of the hematite nanocrystals exhibits obvious enhancement after fluorine doping, making the doped hematite play as an effective self-co-catalyst for photoelectrochemical water splitting. The optimization strategy proposed in this work by simultaneously tuning the intrinsic OER activity and light absorption may shed light on the future design of photocatalysts for energy-related applications.
      PubDate: 2017-08-12T02:25:29.241701-05:
      DOI: 10.1002/cssc.201701074
       
  • Electrochemical Reduction of Carbon Dioxide in a Monoethanolamine Capture
           Medium
    • Authors: Jie Zhang; Lu Chen, Fengwang Li, Ying Zhang, Cameron Bentley, Mike Horne, Alan Bond
      Abstract: Electrocatalytic reduction of CO2 present in a 30% (w/w) monoethanolamine (MEA) aqueous solution has been undertaken at In, Sn, Bi, Pb, Pd, Ag, Cu and Zn metal electrodes. Upon dissolution of CO2, the non-conducting MEA solution is transformed into a conducting one, as needed for electrochemical reduction of CO2. Both an increase in the electrode surface porosity and addition of surfactant cetyltrimethylammonium bromide (CTAB) suppress the competing hydrogen evolution reaction with the latter having a significantly stronger impact. The combination of a porous metal electrode and 0.1% (w/w) of CTAB allows molecular CO2 to be reduced to CO and formate ([HCOO]-) with the product distribution being highly dependent on the identity of the metal electrode used. At a potential of -0.8 V vs. RHE, and use of coralline-like structured indium electrode, faradaic efficiencies for generation of CO and [HCOO]- are 22.8% and 54.5%, respectively compared to efficiencies of 2.9% and 60.8% with a porous lead electrode and 38.2% and 2.4% with a porous silver electrode. Extensive data for the other 5 electrodes are also provided. In addition to identifying optimal conditions for CO2 reduction, mechanistic details for reaction pathways are proposed in this proof of concept electrochemical study in a CO2 capture medium. Conditions and features needed to achieve industrially and commercially viable CO2 reduction in an amine based capture medium are considered.
      PubDate: 2017-08-10T21:25:32.953267-05:
      DOI: 10.1002/cssc.201701075
       
  • Two-Dimensional Materials as Prospective Scaffolds for Mixed-Matrix
           Membrane-Based CO2 Separation
    • Authors: Xiang Zhu; Chengcheng Tian, Chi-Linh Do-Thanh, Sheng Dai
      Abstract: Membrane-based CO2 separation technology plays a significant role in environmental remediation and clean energy. Two-dimensional (2D) materials with atomically precise structures have emerged as prospective scaffolds to develop mixed-matrix membranes (MMMs) for gas separation. Summarized in this perspective review are the latest breakthrough studies in the synthesis of 2D-material-based MMMs to separate CO2 from gas mixtures. 2D materials including graphene oxide (GO), metal–organic framework (MOF)-derived nanosheets, covalent organic frameworks (COFs), and transition metal dichalcogenides (TMDs), as fascinating building blocks, have been comprehensively summarized, together with a focus on synthetic processes and gas separation properties. Challenges and the latest advances in the manufacture of novel synthetic 2D materials are briefly discussed to foresee emerging opportunities for the development of new generations of 2D-material-based MMMs.Mixed business: Summarized in this Review are the latest breakthrough studies in the synthesis of 2D-material-based mixed-matrix membrane (MMMs) to separate CO2 from gas mixtures. 2D materials including graphene oxide (GO), metal–organic framework (MOF)-derived nanosheets, covalent organic frameworks (COFs), and transition metal dichalcogenides (TMDs), as fascinating building blocks, are discussed, with a focus on synthetic processes and gas separation properties.
      PubDate: 2017-08-10T10:43:25.162515-05:
      DOI: 10.1002/cssc.201700801
       
  • Low-Recombination Thieno[3,4-b]thiophene-based Photosensitizers for DSCs
           with Panchromatic IPCE Responses
    • Authors: Phillip Brogdon; Hammad Cheema, Jared Heath Delcamp
      Abstract: We report four NIR photosensitizers employing a low-recombination donor and a thieno[3,4-b]thiophene (3,4-TT) π-bridge for use in dye-sensitized solar cells. The inclusion of electron rich π-spacers red-shifts the dye absorbance with solution absorption onsets reaching 700 nm. Dyes were found to have suitable energy levels for rapid electron transfers via cyclic voltammetry and UV-Vis-NIR absorption spectroscopy. Computationally optimized ground-state geometries show an increased torsional angle between π-spacer and π-bridge brought about by an added alkyl chain resulting in a widened optical band gap and increased oxidation potentials due to a weakening of the electron accepting ability of 3,4-TT for solution measurements. Interestingly in terms of device parameters, the alkylated π-spacer had a nearly identical incident photon-to-current conversion efficiency curve onset suggesting more similar dye geometries on the surface of TiO2. Elevated JSC values and comparable VOC values were observed in the alkylated π-spacer dye-based devices with power conversion efficiencies up to 6.8% observed with IPCE onsets exceeding 800 nm.
      PubDate: 2017-08-08T21:21:17.034053-05:
      DOI: 10.1002/cssc.201701259
       
  • Highly efficient sulfonic/carboxylic dual-acid synergistic catalysis for
           esterification enabled by sulfur-rich graphene oxide (GO-S)
    • Authors: Honglei Zhang; Xiang Luo, Kaiqi Shi, Tao Wu, Feng He, Shoubin Zhou, George Chen, Chuang Peng
      Abstract: A new sulfonic/carboxylic dual-acid catalyst based on sulfur-rich graphene oxide (GO-S) was readily prepared and used as a highly efficient and reusable solid acid catalyst towards the esterification of oleic acid with methanol for biodiesel production. Higher yields of methyl oleate (98 %) and over 3 times higher turnover frequencies (TOF) were observed for the GO-S dual-acid catalyst, compared to liquid sulfuric acid or other carbon-based solid acid catalysts. The "acidity" of sulfonic acid groups was enhanced by the addition of carboxylic acid groups since the combination of the two acids enhances their inherent activity by associative interaction.
      PubDate: 2017-08-08T00:15:21.929959-05:
      DOI: 10.1002/cssc.201700950
       
  • Exploitation of catalytic promiscuity of hemoglobin for NAD(P)+ in situ
           regeneration in dehydrogenase-catalyzed oxidation of furanics
    • Authors: Hao-Yu Jia; Min-Hua Zong, Hui-Lei Yu, Ning Li
      Abstract: In this work, catalytic promiscuity of hemoglobin (Hb) was explored for regeneration of oxidized nicotinamide cofactors (NAD(P)+). With H2O2 as oxidant, Hb was able to efficiently oxidize NAD(P)H into NAD(P)+ in 30 min. The new NAD(P)+ regeneration system was coupled with horse liver alcohol dehydrogenase (HLADH) for the oxidation of bio-based furanics such as furfural and 5-hydroxymethylfurfural (HMF). The target acids (e.g., 2,5-furandicarboxylic acid, FDCA) were afforded with moderate to good yields. In addition, the enzymatic regeneration method was applied in L-glutamic DH-mediated oxidative deamination of L-glutamate and L-lactic DH-mediated oxidation of L-lactate, which furnished α-ketoglutarate and pyruvate, respectively, with the yields of 97% and 81%. The total turnover number (TTN) up to approximately 5000 for cofactor and the E factor of less than 110 were obtained in the bi-enzymatic cascade synthesis of α-ketoglutarate. Overall, a proof-of-concept based on catalytic promiscuity of Hb was provided for in situ regeneration of NAD(P)+ in DH-catalyzed oxidation reactions.
      PubDate: 2017-08-07T21:26:12.980599-05:
      DOI: 10.1002/cssc.201701288
       
  • Performance and ageing robustness of graphite/NMC pouch prototypes
           manufactured through eco-materials and processes
    • Authors: Nicholas Loeffler; Guk-Tae Kim, Stefano Passerini, Cesar Gutierrez, Iosu Cendoya, Iratxe de Meatza, Fabrizio Alessandrini, Giovanni Battista Appetecchi
      Abstract: Graphite/lithium nickel-manganese-cobalt oxide, stacked pouch cells with nominal capacity of 15-18 A h were designed, developed and manufactured for automotive applications in the frame of the European Project GREENLION. A natural, water-soluble material was used as the main electrode binder, thus allowing the employment of H2O as the only processing solvent. The electrode formulations were developed, optimized and up scaled for cell manufacturing. Prolonged cycling and ageing tests have revealed excellent capacity retention and robustness towards degradation phenomena. For instance, above 99% of the initial capacity is retained upon 500 full charge/discharge cycles, corresponding to a fading of 0.004% per cycle, and about 80% of the initial capacity is delivered after 8 months ageing at 45 °C. The stacked soft-packaged cells have shown very reproducible characteristics and performance, reflecting the goodness of design and manufacturing.
      PubDate: 2017-08-07T10:20:20.320455-05:
      DOI: 10.1002/cssc.201701087
       
  • Iron-Doped BaMnO3 for Hybrid Water Splitting and Syngas Generation
    • Authors: Vasudev Pralhad Haribal; Feng He, Amit Mishra, Fanxing Li
      Abstract: A rationalized strategy to optimize transition-metal-oxide-based redox catalysts for water splitting and syngas generation through a hybrid solar-redox process is proposed and validated. Monometallic transition metal oxides do not possess desirable properties for water splitting; however, density functional theory calculations indicate that the redox properties of perovskite-structured BaMnxFe1−xO3−δ can be varied by changing the B-site cation compositions. Specifically, BaMn0.5Fe0.5O3−δ is projected to be suitable for the hybrid solar-redox process. Experimental studies confirm such predictions, demonstrating 90 % steam-to-hydrogen conversion in water splitting and over 90 % syngas yield in the methane partial-oxidation step after repeated redox cycles. Compared to state-of-the-art solar-thermal water-splitting catalysts, the rationally designed redox catalyst reported is capable of splitting water at a significantly lower temperature and with ten-fold increase in steam-to-hydrogen conversion. Process simulations indicate the potential to operate the hybrid solar-redox process at a higher efficiency than state-of-the-art hydrogen and liquid-fuel production processes with 70 % lower CO2 emissions for hydrogen productionPerovskite power: BaMn0.5Fe0.5O3−δ demonstrates over 90 % water-splitting conversion and over 90 % syngas-yield using a hybrid solar-redox process. Computational modelling, fluidized-bed experiments, and in situ XRD analysis indicate that perovskite BaMn0.5Fe0.5O3−δ is ideal for the proposed redox reactions. Process simulations indicate a 70 % reduction in CO2 emissions for hydrogen production compared to the current state-of-the-art processes.
      PubDate: 2017-08-07T06:41:27.409496-05:
      DOI: 10.1002/cssc.201700699
       
  • Electrochemical Reduction of Protic Supercritical CO2 on Copper Electrodes
    • Authors: Olga Melchaeva; Patrick Voyame, Victor Costa Bassetto, Michael Prokein, Manfred Renner, Eckhard Weidner, Marcus Petermann, Alberto Battistel
      Abstract: The electrochemical reduction of carbon dioxide is usually studied in aqueous solutions under ambient conditions. However, the main disadvantages of this method are high hydrogen evolution and low faradaic efficiencies of carbon based products. Supercritical CO2 (scCO2) can be used as a solvent itself to suppresses hydrogen evolution and tune carbon based product yield, however, it received low attention. Therefore, the focus of this study was on the electrochemical reduction of supercritical CO2 (at 40 ˚C and 80 bar). The conductivity of scCO2 was increased through addition of supporting electrolyte and co-solvent (acetonitrile). Besides, the addition of protic solutions with different pH to supercritical CO2 was investigated. 1 M H2SO4, trifluoroethanol, H2O, KOH, and CsHCO3 solutions were used to determine the effect on current density, faradaic efficiency, and selectivity of scCO2 reduction. Reduction of supercritical CO2 to methanol and ethanol were reported for the first time. However, methane and ethylene were not observed. Additionally, corrosion of Cu was noticed.
      PubDate: 2017-08-07T04:15:23.298037-05:
      DOI: 10.1002/cssc.201701205
       
  • Fast and robust: novel highly active N,O zinc guanidine catalysts for the
           ring-opening polymerisation of lactide
    • Authors: Sonja Herres-Pawlis; Pascal Schäfer, Martin Fuchs, Andreas Ohligschläger, Ruth Rittinghaus, Paul McKeown, Enver Akin, Maximilian Schmidt, Alexander Hoffmann, Marcel Liauw, Matthew D. Jones
      Abstract: New zinc guanidine complexes with N,O donor functionalities have been prepared, characterized by X-Ray crystallography and examined for their catalytic activity in the solvent-free ring-opening polymerization (ROP) of technical-grade rac-lactide at 150 °C. All complexes showed a high activity. The fastest complex [ZnCl2(DMEGasme)] (C1) produced colorless poly(lactide) (PLA) after 90 min with a conversion of 52 % and high molar masses (Mw = 69100, PD = 1.4). The complexes have been tested with different monomer-to-initiator ratios to determine the rate constant kp. Furthermore, a polymerization with the most active complex C1 has been monitored by in situ Raman spectroscopy. Overall, conversion up to 90 % can be obtained. To clarify the mechanism end-group analysis has been performed. All four complexes combine robustness against impurities in the lactide with high polymerization rates, and they represent the fastest robust lactide ROP catalysts to date, opening new avenues to a sustainable ROP catalyst family for industrial use.
      PubDate: 2017-08-05T00:06:35.032423-05:
      DOI: 10.1002/cssc.201701237
       
  • Catalyst particle density controls hydrocarbon product selectivity in CO2
           electroreduction on CuOx
    • Authors: Xingli Wang; Ana Sofia Varela, Arno Bergmann, Stefanie Kuehl, Peter Strasser
      Abstract: A key challenge of the carbon dioxide electroreduction (CO2RR) on Cu-based nanoparticles is its low faradic selectivity towards higher-value products such as ethylene. Here, we demonstrate a facile method for tuning the hydrocarbon selectivities on CuOx nanoparticle ensembles by varying the nanoparticle areal density. The sensitive dependence of the experimental ethylene selectivity on catalyst particle areal density is attributed to a diffusional interparticle coupling which controls the de- and re-absorption of CO and thus the effective coverage of COad intermediates. Thus, higher areal density constitutes dynamically favoured conditions for CO re-adsorption and *CO dimerization leading to ethylene formation independent of pH and applied overpotential.
      PubDate: 2017-08-04T03:00:39.194668-05:
      DOI: 10.1002/cssc.201701179
       
  • Low-Cost Perovskite Solar Cells Employing
           Dimethoxydiphenylamine-Substituted Bistricyclic Aromatic Enes as Hole
           Transport Materials
    • Authors: Kasparas Rakstys; Sanghyun Paek, Giulia Grancini, Peng Gao, Vygintas Jankauskas, Abdullah M. Asiri, Mohammad Khaja Nazeeruddin
      Abstract: The synthesis, characterization and photovoltaic performance of series of novel molecular hole transport materials (HTMs) based on bistricyclic aromatic enes (BAEs) are presented. The new derivatives were obtained following a simple and straightforward procedure from inexpensive starting reagents mimicking the synthetically challenging 9,9′-spirobifluorene moiety of the well-studied spiro-OMeTAD. The novel HTMs were tested in mixed cations and anions perovskite solar cells (PSCs) yielding a power conversion efficiency (PCE) of 19.2 % under standard global 100 mW cm−2 AM1.5G illumination using 9-{2,7-bis[bis(4-methoxyphenyl)amino]-9H-fluoren-9-ylidene}-N2,N2,N7,N7-tetrakis(4-methoxyphenyl)-9H-thioxanthene-2,7-diamine (coded as KR374). The power conversion efficiency data confirms the easily attainable heteromerous fluorenylidenethioxanthene structure as valuable core for low-cost and highly efficient HTM design and paves the way towards cost-effective PSC technology.Bridge to success: We report the synthesis of three new hole transport materials (HTMs) using a cost-effective procedure and the impact of different atoms in heteromerous bistricyclic aromatic ene scaffolds. S-bridged KR374 shows a a significantly improved hole-drift mobility leading to enhanced photovoltaic performance in mixed-ion perovskite solar cells and reduced hysteresis owing to the improved interface between the perovskite and HTM caused by stronger Pb–S interaction.
      PubDate: 2017-08-03T07:10:42.610341-05:
      DOI: 10.1002/cssc.201700974
       
  • Plasmonic Gold Nanostars Incorporated into High-Efficiency Perovskite
           Solar Cells
    • Authors: Munkhbayar Batmunkh; Thomas J. Macdonald, William J. Peveler, Abdulaziz S. R. Bati, Claire J. Carmalt, Ivan P. Parkin, Joseph G. Shapter
      Abstract: Incorporating appropriate plasmonic nanostructures into photovoltaic (PV) systems is of great utility for enhancing photon absorption and thus improving device performance. Herein, the successful integration of plasmonic gold nanostars (AuNSs) into mesoporous TiO2 photoelectrodes for perovskite solar cells (PSCs) is reported. The PSCs fabricated with TiO2-AuNSs photoelectrodes exhibited a device efficiency of up to 17.72 %, whereas the control cells without AuNSs showed a maximum efficiency of 15.19 %. We attribute the origin of increased device performance to enhanced light absorption and suppressed charge recombination.Golden star: Plasmonic gold nanostars are incorporated into mesoporous TiO2 photoelectrodes to fabricate high efficiency perovskite solar cells. A power conversion efficiency of 17.72 % is achieved using TiO2-AuNSs photoelectrode-based device.
      PubDate: 2017-08-03T07:05:27.258965-05:
      DOI: 10.1002/cssc.201701056
       
  • Chemo-enzymatic synthesis of a novel borneol-based polyester
    • Authors: Steffen Roth; Irina Funk, Michael Hofer, Volker Sieber
      Abstract: Terpenes are a class of natural compounds that have recently moved into the focus as bio-based resource for chemicals productions due to their abundance, their mostly cyclic structure and the presence of olefin or single hydroxyl groups. In order to apply this raw material in new industrial fields, a second hydroxyl group is inserted into borneol by cytochrome P450cam (CYP101) enzymes in a whole cell catalytic biotransformation with Pseudomonas putida KT2440. Next, a semi-continuous batch system was developed to produce 5-exo-hydroxyborneol with a final concentration of 0.54 g L-1. The bifunctional terpene was then used for the synthesis of an all bio-based polyesters by a solvent free polycondensation reaction. The resulting polymer showed a glass transition temperature around 70 °C and a molecular weight in the range of 2,000 - 4,000 g mol-1 (Mw). These results show that whole cell catalytic biotransformation of terpenes could lead to bio-based, higher-functionalized monomers, which might be basic raw materials for different fields of application, such as biopolymers.
      PubDate: 2017-08-03T03:00:43.382876-05:
      DOI: 10.1002/cssc.201701146
       
  • Chemical Pulping Advantages of Zip-lignin Hybrid Poplar
    • Authors: Shengfei Zhou; Troy Runge, Steven Karlen, John Ralph, Eliana Gonzales-Vigil, Shawn Mansfield
      Abstract: Hybrid poplar genetically engineered to possess chemically labile ester linkages in its lignin backbone (Zip-lignin™ hybrid poplar) was examined to determine if the strategic lignin modifications would enhance chemical pulping efficiencies. Kraft pulping of Zip-lignin and wild-type hybrid poplar was carried out in lab-scale reactors under varying severity conditions of time, temperature and chemical charge. The resulting pulps were analyzed for yield, residual lignin content, and cellulose DP (degree of polymerization), as well as changes in carbohydrates and lignin structure. Statistical models of pulping were created, and the pulp bleaching and physical properties evaluated. Compared to wild-type, the Zip-lignin hybrid poplar cooked under identical conditions showed extended delignification, confirming the Zip-lignin effect. Additionally, yield and carbohydrate content of the ensuing pulps were slightly elevated, as was the cellulose DP for Zip-lignin poplar pulp, although differences in residual lignin between Zip-lignin and wild-type poplar were not detected. Statistical prediction models facilitated comparisons between pulping conditions that resulted in identical delignification, with the Zip-lignin poplar needing milder cooking conditions and resulting in higher pulp yield (up to 1.41% gain). Bleaching and physical properties were equivalent between the samples with slight chemical savings realized in the Zip-lignin samples due to the enhanced delignification.
      PubDate: 2017-08-02T11:00:21.177803-05:
      DOI: 10.1002/cssc.201701317
       
  • Replacement of Biphenyl by Bipyridine Enabling Powerful Hole Transport
           Materials for Efficient Perovskite Solar Cells
    • Authors: Fei Wu; Yahan Shan, Jianhui Qiao, Cheng Zhong, Rui Wang, Qunliang Song, Linna Zhu
      Abstract: Here, 2,2′- and 3,3′-bipyridine are introduced for the first time as the core structure to get two new hole transport materials (HTMs), namely F22 and F33. The electron-withdrawing nature of bipyridine lowers the HOMO level of the new compounds and enhances the open-circuit voltage of perovskite solar cells. Especially for F33, the better planarity leads to better conjugation in the whole molecule and the molecular interaction is enhanced. Hole-mobility tests, steady-state photoluminescence (PL) spectra as well as time-resolved PL decay results demonstrate that the new HTMs exhibit good hole extraction and hole-transporting property. Impressive power conversion efficiencies of 17.71 and 18.48 % are achieved in conventional planar perovskite (CH3NH3PbI3−xClx) solar cells containing F22 and F33 as HTMs, respectively. As far as we know, this is the first report on bypiridine-based HTMs with leading efficiencies, and the design motif in this work opens a new way for devising HTMs in the future.Bip, bip: Bipyridine is introduced for the first time as the core structure for new hole transport materials (HTMs). Remarkable power conversion efficiencies of 17.71 and 18.48 % are achieved in conventional planar perovskite (CH3NH3PbI3−xClx) solar cells by using the newly devised HTMs.
      PubDate: 2017-08-02T06:11:24.644054-05:
      DOI: 10.1002/cssc.201700973
       
  • CsPb2Br5 Single Crystals: Synthesis and Characterization
    • Authors: Ibrahim Dursun; Michele De Bastiani, Bekir Turedi, Badriah Alamer, Aleksander Shkurenko, Jun Yin, Issam Gereige, Ahmed Alsaggaf, Omar F. Mohammed, Mohamed Eddaoudi, Osman M. Bakr
      Abstract: CsPb2Br5 is a ternary halogen-plumbate material with close characteristics to well-reported halide perovskites. Due to its unconventional two-dimensional structure, CsPb2Br5 is being looked at broadly for potential applications in optoelectronics. CsPb2Br5 investigations are currently limited to nanostructures and powder forms of the material, which present unclear and conflicting optical properties. In this study, we present the synthesis and characterization of CsPb2Br5 bulk single crystals, which enabled us to finally clarify the material's optical features. Our CsPb2Br5 crystal has a two-dimensional structure with Pb2Br5- layers spaced by Cs+ cations, and exhibits a ~3.1 eV indirect bandgap with no emission in the visible spectrum.
      PubDate: 2017-08-01T21:00:37.064473-05:
      DOI: 10.1002/cssc.201701131
       
  • Voronoi Tessellated Graphite Produced by Low Temperature Catalytic
           Graphitization of Renewable Hard Carbon
    • Authors: Leyi Zhao; Xiuyun Zhao, Luke Burke, Craig Bennett, Richard Dunlap, Mark Obrovac
      Abstract: A highly crystalline graphite powder was prepared from the low temperature (800-1000 °C) graphitization of renewable hard carbon precursors using a magnesium catalyst. The resulting graphite particles are composed of Voronoi tessellated regions comprising irregular sheets, each Voronoi tessellated region having a small "seed" particle located near their centroid on the surface. This suggests nucleated outward growth of graphitic carbon, which has not been previously observed. Each seed particle consists of a spheroidal graphite shell on the inside of which hexagonal graphite platelets are perpendicularly affixed. This results in a unique high surface area graphite with a high degree of graphitization that is made with renewable feedstocks at temperatures far below that conventionally used for artificial graphites.
      PubDate: 2017-08-01T14:00:38.84326-05:0
      DOI: 10.1002/cssc.201701211
       
  • Hindered Amine Light Stabilizers increase stability of Methylammonium Lead
           Iodide Perovskite against Light and Oxygen
    • Authors: Juan L. Delgado; Nevena Marinova, marius Franckevičius, Ieva Matulaitienė, Andrius Devižis, Gediminas Niaura, Vidmantas Gulbinas
      Abstract: Methylammonium lead iodide perovskite (MAPI) is a promising material for highly-efficient photovoltaic devices. However, it suffers from photooxidation, which imposes strict requirements for its protection from oxygen during processing and operation. Herein we report the unprecedented stabilization effect of hindered amine light stabilizer (HALS) on methylammonium iodide (MAI) and MAPI against photooxidation. We found that HALS prevents the degradation of MAI by inhibiting the oxidation of iodide to iodine. Chemical modification of HALS allows us to incorporate it in MAPI films which extends the resistivity of MAPI against photodegradation at ambient air from a couple of hours to several days, while causing no significant changes in key properties, such as optical absorption and charge transport. These results represent an important advance in the fight against MAPI decomposition and demonstrate for the first time that antioxidants improve the stability of MAPI.
      PubDate: 2017-08-01T06:22:03.273079-05:
      DOI: 10.1002/cssc.201700707
       
  • Efficient and Chemoselective Semihydrogenation of Alkynes Catalyzed by Pd
           Nanoparticles Immobilized on Heteroatom-Doped Hierarchical Porous Carbon
           Derived from Bamboo Shoots
    • Authors: yong yang; Guijie Ji, Yanan Duan, Shaochun Zhang, Benhua Fei, Xiufang Chen
      Abstract: Highly dispersed palladium nanoparticles (Pd NPs) immobilized by a heteroatom-doped hierarchical porous carbon support (N,O-Carbon) with large specific surface areas are synthesized by a wet chemical reduction method, wherein the N,O-Carbon derived from naturally available and reusable bamboo shoots is fabricated by a tandem hydrothermal-carbonization process without assistance of any templates or chemical activation reagents or exogenous N and O source in a simple and eco-friendly manner. The prepared Pd@N,O-Carbon catalyst shows extremely high activity and excellent chemoselectivity for semihydrogeantion of a broad range of alkynes to versatile and valuable alkenes under ambient conditions. The catalyst can be readily recovered for successive reuse with negligible loss in activity and selectivity and is also applicable for gram-scale transformation, which highlights its highly practical potential.
      PubDate: 2017-08-01T05:20:36.896653-05:
      DOI: 10.1002/cssc.201701127
       
  • Effect of Nitrogen Doping Level on the Performance of N-Doped Carbon
           Quantum Dot/TiO2 Composites for Photocatalytic Hydrogen Evolution
    • Authors: Run Shi; Zi Li, Huijun Yu, Lu Shang, Chao Zhou, Geoffrey I. N. Waterhouse, Li-Zhu Wu, Tierui Zhang
      Abstract: Carbon quantum dots (CQDs) have attracted widespread interest for photocatalytic applications, owing to their low cost and excellent electron donor/acceptor properties. However, their advancement as visible-light photosensitizers in CQDs/semiconductor nanocomposites is currently impaired by their poor quantum yields (QYs). Herein, we describe the successful fabrication of a series of nitrogen-doped CQDs (NCDs) with N/C atomic ratios ranging from 0.14–0.30. NCDs with the highest N-doping level afforded a remarkable external QY of 66.8 % at 360 nm, and outstanding electron transfer properties and photosensitization efficiencies when physically adsorbed on P25 TiO2. A NCDs/P25-TiO2 hybrid demonstrated excellent performance for hydrogen evolution in aqueous methanol under both UV and visible-light illumination relative to pristine P25 TiO2. Controlled nitrogen doping of CQDs therefore represents a very effective strategy for optimizing the performance of CQDs/semiconductor hybrid photocatalysts.Dots the way, a-ha, a-ha, I like it: N-doped carbon quantum dots (NCDs) with high N/C atomic ratios (0.14–0.30) were fabricated by a facile hydrothermal process. N-doping suppressed nonradiative quenching in the NCDs, delivering photoluminescence quantum yields as high as 68 %. NCDs/P25-TiO2 composites showed good activity for photocatalytic H2 evolution under both UV and visible illumination, which can be attributed to efficient excitation wavelength-dependent interfacial charge transfer.
      PubDate: 2017-07-31T07:46:39.038271-05:
      DOI: 10.1002/cssc.201700943
       
  • Strongly Coupled Molybdenum Carbide@Carbon Sheets as a Bifunctional
           Electrocatalyst for Overall Water Splitting
    • Authors: Hao Wang; Yingjie Cao, Cheng Sun, Guifu Zou, Jianwen Huang, Xiaoxiao Kuai, Jianqing Zhao, Lijun Gao
      Abstract: High-performance and affordable electrocatalysts from earth-abundant elements are desirably pursued for water splitting involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this work, a bifunctional electrocatalyst of highly crystalline Mo2C nanoparticles supported on carbon sheets (Mo2C@CS) is designed towards overall water splitting. Owing to the highly active catalytic nature of Mo2C nanoparticles, the high surface area of carbon sheets and the efficient charge transfer in the strongly coupled composite, the designed catalysts show excellent bifunctional behavior with an onset potential of -60 mV for HER and an overpotential of 320 mV to achieve a current density of 10 mA cm-2 for OER in 1 M KOH while maintaining robust stability. Meanwhile, the cell using the catalyst only requires a low cell voltage of 1.73 V to achieve a current density of 10 mA cm-2 and maintains the activity for more than 100 hours when employing the Mo2C@CS catalyst as both anode and cathode electrodes in a water electrolyzer. Such high performance makes Mo2C@CS a promising electrocatalyst for practical hydrogen production from water splitting.
      PubDate: 2017-07-30T21:20:57.988675-05:
      DOI: 10.1002/cssc.201701276
       
  • A Complete Selectivity for the Direct Synthesis of Hydrogen Peroxide over
           Palladium-Tellurium Catalysts at Ambient Pressure
    • Authors: Pengfei Tian; Xingyan Xu, Can Ao, Doudou Ding, Wei Li, Rui Si, Weifeng Tu, Jing Xu, Yi-Fan Han
      Abstract: Highly selective hydrogen peroxide (H2O2) synthesis directly from H2 and O2 is a strongly desired reaction for green process. We report a highly efficient palladium-tellurium (Pd-Te/TiO2) catalyst with a selectivity of ~100% toward H2O2 under mild conditions (283 K, 0.1 MPa and a semi-batch continuous flow reactor). The size of Pd particles was remarkably reduced from 2.1 nm to 1.4 nm with the addition of Te; meanwhile, the surface Pd atoms modified by Te could significantly weaken the dissociative activation of O2, leading to the non-dissociative hydrogenation of O2. Density functional theory (DFT) calculations illuminated the critical role of Te in the selective hydrogenation of O2 that the active sites composed of Pd and Te could significantly restrain the side reactions. This work has made a significant progress on the development of high-selectivity catalysts for the direct synthesis of H2O2 at ambient pressure.
      PubDate: 2017-07-28T01:56:07.436752-05:
      DOI: 10.1002/cssc.201701238
       
  • Broadband Emitting 2D-Hybrid Organic Inorganic Perovskite Based on
           Cyclohexane-bis(methylamonium) Cation
    • Authors: Ishita neogi; Annalisa Bruno, Damodaran Bahulayan, Teck Wee Goh, Biplab Ghosh, Rakesh Ganguly, Daniele Cortecchia, Tze Chien Sum, Cesare Soci, Nripan Mathews, Subodh Gautam Mhaisalkar
      Abstract: A novel broadband emitting 2D-hybrid organic inorganic perovskite (CyBMA)PbBr4 based on highly flexible cis-1,3-bis(methylaminohydrobromide)cyclohexane (CyBMABr) core has been designed, synthesized and investigated, highlighting the effects of stereoisomerism of the templating cation on the formation and properties of the resulting perovskite. The new 2D-material has high exciton binding energy of 340 meV and a broad emission spanning from 380-750 nm, incorporating a prominent excitonic band and a less intense broad peak at room temperature. Prominent changes in the photoluminescence spectrum were observed at lower temperatures, showing remarkable enhancement in the intensity of broad band at the cost of excitonic emission. Temperature dependent PL mapping indicate the effective role of only a narrow band of excitonic absorption in the generation of the active channel for emission. Based on the evidences obtained from the photo-physical investigations, we attributed the evolution of the broad B-band of (CyBMA)PbBr4 to excitonic self-trapped states
      PubDate: 2017-07-28T00:55:49.501421-05:
      DOI: 10.1002/cssc.201701227
       
  • Robust Cooperative Photooxidation of Sulfides without Sacrificial Reagent
           under Air Using A Dinuclear RuII-CuII Assembly
    • Authors: Duobin Chao; Mengying Zhao
      Abstract: A molecular chromophore-catalyst assembly containing a chromophore ruthenium(II) center (RuIIchro) and a catalytic copper(II) center (CuIIcat) has been prepared facilely. The assembly was employed for photocatalytic oxidation of sulfides without sacrificial reagent in the presence of dioxygen under blue light irradiation. Unprecedented turnover number (TON) up to 32000 was achieved. It was elucidated that an electron transferred from excited state of chromophore RuII*chro to CuIIcat along with generation of CuIcat that was further activated by O2. These results demonstrate a promising strategy for efficient cooperative photocatalytic reactions under air using chromophore-catalyst assembly.
      PubDate: 2017-07-26T09:25:31.146396-05:
      DOI: 10.1002/cssc.201700930
       
  • Factors Influencing the Mechanical Properties of Formamidinium Lead
           Halides and Related Hybrid Perovskites
    • Authors: Shijing Sun; Furkan H. Isikgor, Zeyu Deng, Fengxia Wei, Gregor Kieslich, Paul D. Bristowe, Jianyong Ouyang, Anthony K. Cheetham
      Abstract: The mechanical properties of formamidinium lead halide perovskites (FAPbX3, X=Br or I) grown by inverse-temperature crystallization have been studied by nanoindentation. The measured Young's moduli (9.7–12.3 GPa) and hardnesses (0.36–0.45 GPa) indicate good mechanical flexibility and ductility. The effects of hydrogen bonding were evaluated by performing ab initio molecular dynamics on both formamidinium and methylammonium perovskites and calculating radial distribution functions. The structural and chemical factors influencing these properties are discussed by comparison with corresponding values in the literature for other hybrid perovskites, including double perovskites. Our results reveal that bonding in the inorganic framework and hydrogen bonding play important roles in determining elastic stiffness. The influence of the organic cation becomes more important for structures at the limit of their perovskite stability, indicated by high tolerance factors.Hard or soft' Nanoindentation on single crystals of FAPbX3 (X=Br or I) is used to study the mechanical properties of formamidinium lead halide perovskites. The effects of hydrogen bonding are evaluated by ab initio molecular dynamics and calculating radial distribution functions.
      PubDate: 2017-07-26T06:16:07.06276-05:0
      DOI: 10.1002/cssc.201700991
       
  • Design Rules for Oxygen Evolution Catalysis at Porous Iron Oxide
           Electrodes: Thousand-Fold Current Density Increase
    • Authors: Sandra Haschke; Dmitrii Pankin, Yuri Petrov, Sebastian Bochmann, Alina Manshina, Julien Bachmann
      Abstract: Nanotubular iron(III) oxide electrodes are optimized for catalytic proficiency in the water oxidation reaction at neutral pH. Nanostructured electrodes are prepared from anodic alumina templates coated with Fe2O3 by atomic layer deposition. Scanning helium ion microscopy, X-ray diffraction and Raman spectroscopy characterize the morphology and phase of samples submitted to various treatments. These methods document the contrasting effects of thermal annealing, on the one hand, and of electrochemical treatment, on the other hand. The electrochemical performance of the corresponding electrodes in dark conditions is quantified by steady-state electrolyses and electrochemical impedance spectroscopy. A rough and amorphous Fe2O3 with phosphate incorporation proves to be optimal in the water oxidation reaction. In combination with the ideal pore length L = 17 μm, the maximized catalytic turnover is reached with an effective current density J = 140 μA cm(-2) at 0.49 V applied overpotential η.
      PubDate: 2017-07-26T04:26:19.037639-05:
      DOI: 10.1002/cssc.201701068
       
  • Aquivion PFSA as an Efficient Pickering Interfacial Catalyst for the
           Hydrolysis of Triglycerides
    • Authors: Marc Pera-Titus; Hui Shi, Bing Hong, Flora Fan
      Abstract: Aquivion® Perfluorosulfonic Superacid catalyzed efficiently the solvent-free hydrolysis of glyceryl trilaurate at 100 oC and ambient pressure via the genesis of stable Pickering emulsions.
      PubDate: 2017-07-25T09:26:38.235951-05:
      DOI: 10.1002/cssc.201700663
       
  • Carbon dioxide capture by aqueous ionic liquid solutions
    • Authors: Jairton Dupont; Nathalia M. Simon, Marcileia Zanatta, Francisco P. dos Santos, Marta C. Corvo, Eurico J. Cabrita
      Abstract: Confined water in aqueous solutions of imidazolium-based ionic liquids (ILs) associated with acetate and imidazolate anions react reversibly with CO2 to yield bicarbonate. Three types of CO2 sorption in these "IL-aqueous solutions" were observed: physical, CO2-imidazolium adduct generation and bicarbonate formation (up to 1.9 mol of bicarbonate/mol of IL), resulting in a 10/1 mol/mol total absorption of CO2 relative to imidazolate anions in the presence of water 1/1000 (IL/water). These sorption values are higher than the classical alkanol amines or even alkaline aqueous solutions under similar experimental conditions.
      PubDate: 2017-07-25T09:26:07.257338-05:
      DOI: 10.1002/cssc.201701044
       
  • Towards extending solar cells life time : Addition of a fluorous cation to
           triple-cation based perovskite films
    • Authors: Manuel Salado; M Asunción Fernández, Juan P Holgado, Samrana Kazim, M. K. Nazeeruddin, P J Dyson, Shahzada Ahmad
      Abstract: Organo metal halide perovskites have emerged as highly promising replacements for thin film solar cells. However, their poor stability under ambient conditions remains problematic, hindering commercial exploitation. Here, we describe our investigation on the incorporation of a fluorous-functionalized imidazolium cation in a highly stable cesium based mixed perovskite material (Cs0.05(MA0.15FA0.85)0.95Pb(I0.85Br0.15)3 and how it influnce enhances stability. The resulting materials, which vary according to the content of the fluorous-functionalized imidazolium cation, display a prolonged tolerance to atmospheric humidity (>100 days) along with power conversion efficiencies exceeding 16%. This work provides a general route which can be implemented in variety of perovskites and highlights a promising way to increase perovskite solar cell stability.
      PubDate: 2017-07-25T04:20:28.148225-05:
      DOI: 10.1002/cssc.201700797
       
  • Pseudocapacitive desalination of brackish water and seawater via vanadium
           pentoxide decorated multi-walled carbon nanotubes
    • Authors: Juhan Lee; Pattarachai Srimuk, Katherine Aristizabal, Choonsoo Kim, Soumyadip Choudhury, Yoon-Chae Nah, Frank Mücklich, Volker Presser
      Abstract: We introduce membrane pseudocapacitive deionization (MPDI) of a hybrid cell consisting of one electrode of hydrated vanadium pentoxide (hV2O5) decorated on multi-walled carbon nanotubes electrode (MWCNT) and one electrode of activated carbon. This hybrid system enables sodium removal by pseudocapacitive intercalation to MWCNT-hV2O5 electrode and chloride removal by non-Faradaic electrosorption of the porous carbon electrode. MWCNT-hV2O5 electrode was synthesized by electrochemical deposition of hydrated vanadium pentoxide on the MWCNT paper. The stable electrochemical operating window for MWCNT-hV2O5 electrode is identified between -0.5 V and +0.4 V vs. Ag/Cl which provides a specific capacity of 44 mAh/g (corresponds with 244 F/g) in aqueous 1 M NaCl. The desalination performance of the MPDI system was investigated in aqueous 200 mM NaCl (brackish water) and 600 mM NaCl (sea water) solutions. With the aid of an anion and a cation exchange membrane, the MPDI hybrid cell was operated from -0.4 V to +0.8 V cell voltage without crossing the reduction and oxidation potential limit of both electrodes. For the 600 mM NaCl solution, the NaCl salt adsorption capacity of the cell was 23.6±2.2 mg/g which is equivalent to 35.7±3.3 mg/g as normalized to the mass of the MWCNT-hV2O5 electrode. Additionally, we propose a normalization method for the electrode material with Faradaic reactions based on sodium uptake capacities.
      PubDate: 2017-07-25T03:00:34.188848-05:
      DOI: 10.1002/cssc.201701215
       
  • 1D and 2D NMR spectroscopy of bonding interactions within stable and
           phase-separating organic electrolyte-cellulose solutions
    • Authors: Matthew T. Clough; Christophe Fares, Roberto Rinaldi
      Abstract: Organic electrolyte solutions (mixtures containing an ionic liquid and a polar, molecular co-solvent) are highly versatile solvents for cellu-lose. However, the underlying solvent-solvent and solvent-solute interactions are not yet fully understood. Herein, mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate, the co-solvent 1,3-dimethyl-2-imidazolidinone, and cellulose are investigated using 1D and 2D NMR spectroscopy. The use of a triply-13C-labelled ionic liq-uid enhances the signal-to-noise ratio for 13C NMR spectroscopy, enabling changes in bonding interactions to be accurately pinpoint-ed. Current observations reveal an additional degree of complexity regarding the distinct roles of cation, anion and co-solvent toward maintaining cellulose solubility and phase stability. Unexpectedly, the interactions between the dialkylimidazolium ring C2-H substituent and cellulose become more pronounced at high temperatures, coun-teracted by a net weakening of acetate-cellulose interactions. More-over, for mixtures that exhibit critical solution behaviour, phase sepa-ration is accompanied by the apparent recombination of cation-anion pairs.
      PubDate: 2017-07-24T04:20:23.797875-05:
      DOI: 10.1002/cssc.201701042
       
  • Nanofiltration-enabled in situ solvent and reagent recycle for sustainable
           continuous-flow synthesis
    • Authors: Tamas Fodi; Christos Didaskalou, Jozsef Kupai, Gyorgy T Balogh, Peter Huszthy, Gyorgy Szekely
      Abstract: The solvent usage in the pharmaceutical sector accounts for as much as 90% of the overall mass during manufacturing processes. Consequently, solvent consumption poses significant costs and environmental burden. Continuous processing, in particular continuous-flow reactors have a great potential in the sustainable production of pharmaceuticals but subsequent downstream processing remains challenging. Separation processes for the concentration and purification of chemicals can account for as much as 80% of the total manufacturing costs. In this work, a nanofiltration unit was coupled to a continuous-flow rector for in situ solvent and reagent recycle. The nanofiltration unit is straightforward to implement and control in a continuous operation. The hybrid process was continuously operated over 6 weeks recycling about 90% of the solvent and the reagent. Consequently, the E factor and the carbon footprint were reduced by 91% and 19%, respectively. Moreover, the nanofiltration unit concentrated the product 11 times and simultaneously increased the purity from 52.4% to 91.5%. The boundaries for process conditions were investigated to facilitate implementation of the methodology by the pharmaceutical sector.
      PubDate: 2017-07-23T21:30:52.310444-05:
      DOI: 10.1002/cssc.201701120
       
  • Conducting Polymers Crosslinked with Sulfur as Cathode Materials for
           High-Rate, Ultralong-Life Lithium-Sulfur Batteries
    • Authors: Ligui Li; Shuaibo Zeng, Lihong Xie, Dengke Zhao, Nan Wang, Shaowei Chen
      Abstract: Low electrical conductivity and lack of chemical confinement are two major factors that limit the rate performance and cycling stability of cathode materials in lithium-sulfur (Li-S) batteries. Herein, sulfur is copolymerized with poly(m-aminothiophenol) (PMAT) nanoplates via inverse vulcanization, leading to a highly crosslinked copolymer cp(S-PMAT) in which about 80 wt% of the feeding sulfur is chemically bonded with the thiol groups of PMAT. The cp(S-PMAT)/C based cathode exhibits a high discharge capacity of 1240 mAh g-1 at 0.1 C, remarkable rate capacity of 880 mAh g-1 at 1 C and 600 mAh g-1 at 5 C; moreover, it can retain a capacity of 495 mAh g-1 after 1000 deep discharge-charge cycles at 2 C, corresponding to a retention of 66.9% and a decay rate of only 0.040% per cycle. Such a remarkable rate performance is attributed to the highly conductive pathways consisting of PMAT nanoplates, while the excellent cycling stability is mainly ascribed to chemical confinement of sulfur with a large number of stable covalent bonds between sulfur and thiol groups of PMAT. The results suggest a viable paradigm in the design and engineering of conducting polymers with reactive functional groups as effective electrode materials for high-performance Li-S batteries.
      PubDate: 2017-07-23T21:30:33.200331-05:
      DOI: 10.1002/cssc.201700913
       
  • Stabilizing the performance of high-capacity sulfur composite electrodes
           by a novel gel polymer electrolyte configuration
    • Authors: Marco Agostini; Du Hyun Lim, Matthew Sadd, Fasciani Chiara, Maria Assunta Navarra, Stefania Panero, Sergio Brutti, Aleksandar Matic, Bruno Scrosati
      Abstract: Increased pollution and the consequent increasing in global warming are drawing attention to the larger use of renewable energy sources such as solar or wind. However, the production of energy from most renewable sources is intermittent and thus relies on the availability of electrical energy storage systems with high capacity and at competitive cost. Lithium-sulfur batteries are among the most promising technologies in this respect due to a very high theoretical energy density (1675 mAh g-1) and that the active material, S, is abundant and cheap. However, a so far limited practical energy density, life time and the scaling-up of materials and production processes prevent their introduction into commercial applications. In this work we report on a simple strategy to address these issues by using a novel gel polymer electrolyte (GPE) which enables stable performance close to the theoreticalof a low cost sulfur-carbon composite with high active material loading, i.e. 70% S. We show that the GPE prevents sulfur dissolution and reduces migration of polysulfide species to the anode. This functional mechanism of the GPE membranes is revealed investigating the Li-anode/GPE interphase at various state of discharge/charge using Raman spectroscopy.
      PubDate: 2017-07-21T09:10:26.201256-05:
      DOI: 10.1002/cssc.201700977
       
  • Electrocatalytic Water Oxidation Promoted by 3 D Nanoarchitectured
           Turbostratic δ-MnOx on Carbon Nanotubes
    • Authors: Biaobiao Zhang; Yuanyuan Li, Mario Valvo, Lizhou Fan, Quentin Daniel, Peili Zhang, Linqin Wang, Licheng Sun
      Abstract: The development of manganese-based water oxidation electrocatalysts is desirable for the production of solar fuels, as manganese is earth-abundant, inexpensive, non-toxic, and has been employed by the Photosystem II in nature for a billion years. Herein, we directly constructed a 3 D nanoarchitectured turbostratic δ-MnOx on carbon nanotube-modified nickel foam (MnOx/CNT/NF) by electrodeposition and a subsequent annealing process. The MnOx/CNT/NF electrode gives a benchmark catalytic current density (10 mA cm−2) at an overpotential (η) of 270 mV under alkaline conditions. A steady current density of 19 mA cm−2 is obtained during electrolysis at 1.53 V for 1.0 h. To the best of our knowledge, this work represents the most efficient manganese-oxide-based water oxidation electrode and demonstrates that manganese oxides, as a structural and functional model of oxygen-evolving complex (OEC) in Photosystem II, can also become comparable to those of most Ni- and Co-based catalysts.Turbo-active sites: A 3 D nanoarchitectured turbostratic δ-MnOx is directly constructed on carbon nanotube-modified nickel foam (MnOx/CNT/NF). The MnOx/CNT/NF electrode exhibits excellent performance for electrochemical water oxidation, giving a benchmark catalytic current density (10 mA cm−2) at an overpotential of 270 mV under alkaline conditions.
      PubDate: 2017-07-20T04:50:38.166042-05:
      DOI: 10.1002/cssc.201700824
       
  • C-H carboxylation of aromatic compounds via CO2 fixation
    • Authors: Junfei Luo; Igor Larrosa
      Abstract: Carbon dioxide (CO2) represents the most abundant and accessible carbon source in Earth. Thus the ability to transform CO2 into valuable commodity chemicals via construction of C-C bonds is an invaluable strategy. Carboxylic acids and derivatives, the main products obtained by carboxylation of carbon nucleophiles by reaction of CO2, have wide application in pharmaceuticals and advanced materials. Among the variety of carboxylation methods currently available, the direct carboxylation of C-H bonds with CO2 has attracted much attention due to its advantages from a step- and atom-economical point of view. In particular, the prevalence of (hetero)aromatic carboxylic acid and derivatives among biologically active compounds has led to significant interest in the development of methods for their direct carboxylation from CO2. In this review will discuss the latest achievements in the area of direct C-H carboxylation of (hetero)aromatic compounds with CO2.
      PubDate: 2017-07-19T09:10:46.09985-05:0
      DOI: 10.1002/cssc.201701058
       
  • In-Situ Growth and Wrapping of Aminoanthraquinone Nanowires within 3D
           Graphene Framework as High-Performance Foldable Organic Cathode for
           Lithium Ion Batteries
    • Authors: Guanhui Yang; Fanxing Bu, Yanshan Huang, Yu Zhang, Imran Shakir, Yuxi Xu
      Abstract: Small conjugated carbonyl compounds are intriguing candidates of organic electrode materials because of their abundance, high theoretical capacity and adjustable molecular structure. However, their dissolution in aprotic electrolytes and poor conductivity eclipse them in terms of practical capacity, cycle life and rate capability. Herein, we report a foldable and binder-free nanocomposite electrode consisting of 2-aminoanthraquinone (AAQ) nanowires wrapping within three-dimensional (3D) graphene framework, which is prepared through antisolvent crystallization followed by a facile chemical reduction and self-assembly process. The nanocomposite exhibited a very high capacity of 265 mAh g-1 at 0.1 C for the AAQ, realizing 100% utilization of active material. Furthermore, the nanocomposite shows superior cycling stability (82% capacity retention after 200 cycles at 0.2 C and 76% capacity retention after 1000 cycles at 0.4 C) and excellent rate performance (153 mAh g-1 at 5 C). Particularly, the nanocomposite can deliver the highest capacity of 165 mAh g-1 among all reported anthraquinone and its analogues-based electrodes if based on the mass of the whole electrode, which is essential for practical application. Such outstanding electrochemical performance could be largely attributed to the wrapping structure of the flexible composite, which provides both conductivity and structural integrity.
      PubDate: 2017-07-19T00:30:30.793299-05:
      DOI: 10.1002/cssc.201701175
       
  • A Hydroxamic Acid Anchoring Group for Durable Dye-Sensitized Solar Cells
           with a Cobalt Redox Shuttle
    • Authors: Tomohiro Higashino; Yuma Kurumisawa, Ning Cai, Yamato Fujimori, Yukihiro Tsuji, Shimpei Nimura, Daniel Packwood, Jaehong Park, Hiroshi Imahori
      Abstract: A hydroxamic acid group has been employed for the first time as an anchoring group for cobalt-based dye-sensitized solar cells (DSSCs). The porphyrin dye YD2-o-C8HA with the hydroxamic acid anchoring group exhibited a power conversion efficiency (η) of 6.4%, which is close to that of YD2-o-C8, a representative porphyrin dye with a conventional carboxylic acid one. More importantly, YD2-o-C8HA was found to be superior to YD2-o-C8 in terms of both binding ability to TiO2 and durability of cobalt-based DSSCs. Notably, YD2-o-C8HA cell revealed a higher η-value (4.1%) than YD2-o-C8 (2.8%) after 500 h illumination. These results exemplify that the hydroxamic acid can be used for DSSCs with any transition metal-based redox shuttle to ensure high cell durability as well as excellent photovoltaic performance.
      PubDate: 2017-07-18T23:35:44.153038-05:
      DOI: 10.1002/cssc.201701157
       
  • A new perspective on transparent wood: Lignin-retaining transparent wood
    • Authors: Yuanyuan Li; Qiliang Fu, Ramiro Rojas, Min Yan, Martin Lawoko, Lars Berglund
      Abstract: Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Meanwhile, lignin removal weakens the wood structure, limiting the fabrication of large structure. Here, a green and industrially feasible method was introduced to prepare transparent wood. Up to 80 wt% of lignin was preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high lignin content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23 W/mK, and work-to-fracture of 119.5 J/m3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained is positioned for energy saving buildings.
      PubDate: 2017-07-18T09:50:17.458518-05:
      DOI: 10.1002/cssc.201701089
       
  • In-situ preparation of novel
           layered-spinel-microsphere/reduced-graphene-oxide heterostructured cathode
           for ultrafast charge-discharge Li-ion batteries
    • Authors: Dong Luo; Shaohua Fang, Li Yang, Shin-ichi Hirano
      Abstract: Although Li-rich layered oxides (LLOs) have the highest capacity of any cathodes used at present, their current rate capability is far from meeting the requirements of electric vehicles and smart grids. Here, a novel layered-spinel-microsphere/rGO (LS@rGO) heterostructured cathode is prepared by in-situ technique. This cathode is composed of a spinel phase, two layered structures and a few of reduced graphene oxide (rGO, 1.08 wt% of carbon). It delivers a considerably competitive capacity (145 mA h g-1) at an ultrahigh charge-discharge rate of 60 C (12 A g-1). The ultra-superior rate capability of LS@rGO is closely related with the in-situ introduction of spinel phase and rGO. Moreover, XAS and XPS data indicate Cr ions move from octahedral lattice sites to tetrahedral lattice sites and Mn ions do not participate in the oxidation reaction during the initial charge process.
      PubDate: 2017-07-17T22:16:23.479071-05:
      DOI: 10.1002/cssc.201701207
       
  • A multi-objective optimisation including results of life cycle assessment
           in developing bio-renewables-based processes
    • Authors: Daniel Helmdach; Polina Yaseneva, Parminder K Heer, Artur M Schweidtmann, Alexei Lapkin
      Abstract: A decision support tool has been developed, which uses global multi-objective optimisation based on: (i) the environmental impacts, evaluated within the framework of full life cycle assessment, and (ii) process costs, evaluated using rigorous process models. This approach is particularly useful in developing the bio renewable-based energy solutions and chemicals manufacturing, where multiple criteria must be evaluated and where the optimisation-based decision making process is particularly attractive. The framework is demonstrated using a case study of conversion of terpenes derived from bio-waste feedstocks into reactive intermediates. A two-step chemical conversion/separation sequence was implemented as a rigorous process model and combined with a life cycle model. A life cycle inventory for crude sulfate turpentine was developed, as well as a conceptual process of its separation into pure terpene feedstocks. The performed single- and multi-objective optimisations demonstrate the functionality of the optimisation-based process development and illustrate the approach. Most significant advance is the ability to perform multi-objective global optimisation, resulting in identification of a region of Pareto-optimal solutions.
      PubDate: 2017-07-17T06:16:09.535518-05:
      DOI: 10.1002/cssc.201700927
       
  • Decorating separator with macro/mesoporous Co-N-C for highly efficient
           polysulfides confinement and reutilization in lithium-sulfur batteries
    • Authors: Wen Hu; Yuichiro Hirota, Yexin Zhu, Nao Yoshida, Manabu Miyamoto, Tao Zheng, Norikazu Nishiyama
      Abstract: A macro/mesoporous Co-N-C-decorated separator is proposed to confine and reutilize migrating polysulfides. Endowed with desirable structure and synchronous lithio/sulfiphilic chemistry, macro/mesoporous Co-N-C interface manipulates large polysulfides adsorption uptake, high polysulfides adsorption kinetics, reversible electrocatalysis toward anchored-polysulfides redox, and facile charge transport. It significantly boosts simple MWCNT/S-70wt% cathode achieving high initial capacities (e.g. 1406 mAh g-1 at 0.2 C, 1203 mAh g-1 at 1 C), nearly 100% Coulombic efficiencies, and high reversible capacities after cycle tests (e.g. 828.4 mAh g-1 at 1 C after 100 cycles) at both low and high current rates. These results demonstrate that decorating separator with macro/meso Co-N-C paves a feasible way for developing advanced Li-S batteries.
      PubDate: 2017-07-14T05:25:35.777488-05:
      DOI: 10.1002/cssc.201700999
       
  • Low dimensional organic-inorganic halide perovskite: structure,
           properties, and applications
    • Authors: Ravi K.Misra; Bat-El Cohen, Lior Iagher, Lioz Etgar
      Abstract: Three-dimensional (3D) perovskite has attracted a lot of attention due to its success in photovoltaic (PV) solar cells. However, one the major crucial issues lies in its stability, which has limited its commercialization. An important property of organic-inorganic perovskite is the possibility of forming a layered material using long organic cations that do not fit into the octahedral cage. The long organic cation acts as a "barrier" that "caps" the 3D perovskite forming the layered material. Controlling the number of perovskite layers could provide a confined structure with different chemical and physical properties than 3D perovskite has. This opens up a whole new batch of interesting materials with huge potential for optoelectronic applications. This mini review presents the synthesis, properties, and structural orientation of low-dimensional perovskite. It also discusses the progress of low-dimensional perovskite in PV solar cells, which, to date, have a comparable performance but with enhanced stability in comparison with the 3D perovskite. Finally, the use of low-dimensional perovskite in LEDs and photodetectors is discussed. The low-dimensional perovskites are promising candidates for LED devices, mainly due to their high radiative recombination as a result of the confined low-dimensional quantum well.
      PubDate: 2017-07-13T10:25:26.032361-05:
      DOI: 10.1002/cssc.201701026
       
  • Hybrid deep eutectic solvents with flexible hydrogen-bonded supramolecular
           network for highly efficient uptake of NH₃
    • Authors: Yuhui Li; Mohammad Chand Ali, Qiwei Yang, Zhiguo Zhang, Zongbi Bao, Baogen Su, Huabin Xing, Qilong Ren
      Abstract: The serious environmental problems of modern society creates a great demand for the efficient uptake of NH₃ by solvents. However, many shortcomings exist with the traditional aqueous absorbents, and efforts to use ionic liquids met limited success. In this work, we for the first time report that the design of hybrid deep eutectic solvents (DESs) with flexible hydrogen-bonded supramolecular network enabled both exceptional NH₃ uptake capacity and superior desorption-regeneration performance, along with superb NH₃/CO₂ selectivity and environmental merits. Elucidated by the molecular dynamic simulations and spectrum analysis, the abundant hydrogen-bonding sites in the hybrid DESs grasp the every atom of NH₃ molecule and enable a strong physical reversible solvation, while the multiple interactions among the hybrid components create a flexible hydrogen-bonded supramolecular network and allow for solvent-unbreaking absorption to ensure the full participation of solvent and process stability. A mass solubility of NH₃ up to 0.13 gg-¹ was achieved at 313 K and 101 kPa by the hybrid DES choline chloride/resorcinol/glycerol (1:3:5), higher than all reported ionic liquids and ordinary DESs, and the performance remained the same after ten absorption-desorption cycles with easy regeneration. These results set a new benchmark for the reversible NH₃ absorption and separation by solvents, and would also inspire the more applications of DESs.
      PubDate: 2017-07-13T06:25:23.35114-05:0
      DOI: 10.1002/cssc.201701135
       
  • Efficient Electron Transfer across ZnO-MoS2-RGO Heterojunction for
           Remarkably Enhanced Sunlight Driven Photocatalytic Hydrogen Evolution
    • Authors: Suneel Kumar; Nagappagari Lakshmana Reddy, Himmat Singh Kushwaha, Ashish Kumar, Muthukonda Venkatakrishnan Shankar, Kaustava Bhattacharyya, Aditi Halder, Venkata Krishnan
      Abstract: Development of noble metal free catalysts for hydrogen evolution is the need of the hour for energy applications. In this regard, we designed and synthesized ternary heterojunction nanocomposites, consisting of ZnO nanoparticles anchored on MoS2-RGO nanosheets, as heterogeneous catalysts for highly efficient photocatalytic hydrogen (H2) evolution. In photocatalytic process, catalyst dispersed in electrolytic solution (S2-, SO32-) recorded an enhanced rate of H2 evolution and the optimization experiments reveals that ZnO with 4.0 wt% of MoS2-RGO nanosheets (ZMG4) showed the highest photocatalytic H2 production of 28.616 mmol h-1 gcat-1 under sunlight irradiation, which is about 56 times higher than bare ZnO and several times higher than other ternary photocatalysts. The superior catalytic activity can be attributed to in situ generation of ZnS, which leads to improved interfacial charge transfer to cocatalyst MoS2, in turn RGO where plenty of active sites available for photocatalytic reaction. The recyclability experiments of optimized photocatalyst proved its stability. In addition, the ternary nanocomposites also show its multi-functional properties for hydrogen evolution activity under electrocatalytic and photoelectrocatalytic conditions due to the high electrode-electrolyte contact area. Thus, the present work provides very useful insights in the development of inexpensive, multi-functional catalysts without noble metal loading to achieve high rate of H2 generation.
      PubDate: 2017-07-13T05:30:34.331303-05:
      DOI: 10.1002/cssc.201701024
       
  • Conversion of cellulose to amphiphilic alkyl glycosides catalyzed by
           Aquivion, a perfluorosulfonic acid polymer
    • Authors: François Jérôme; Karine De Oliveira Vigier, Ayman Karam, Boris Estrine, Sinisa Marincovic, Claudio Oldani
      Abstract: Aquivion PFSA PW98 is an amphiphilic solid superacid capable of converting cellulose to Amphiphilic Alkyl Glycosides (AAG) in 85% yield (i.e. 97% selectivity). The present process involves (1) a mechanocatalytic depolymerization of cellulose followed by (2) a direct glycosylation with n-dodecanol. In comparison to H2SO4 and solid acid catalysts commonly employed in cellulose processing, Aquivion PFSA PW98 is not only recyclable but also exhibits superior catalytic performances in terms of yield, selectivity and reactor productivity
      PubDate: 2017-07-11T05:43:54.064286-05:
      DOI: 10.1002/cssc.201700903
       
  • Cooking with active oxygen and solid alkali (CAOSA): a promising
           alternative approach for lignocellulosic biorefineries
    • Authors: Yetao Jiang; Xianhai Zeng, Rafael Luque, Xing Tang, Yong Sun, Tingzhou Lei, Shijie Liu, Lu Lin
      Abstract: Lignocellulosic biomass, a matrix of the biopolymers including cellulose, hemicellulose and lignin, has gathered increasing attention in recent years in the production of chemicals, fuels and materials based on biorefinery processes due to its renewability and availability. Fractionating lignocellulose is considered as the foundational step to establish an economical and sustainable lignocellulosic biorefinery. This Minireview summarized a newly developed oxygen delignification for lignocellulose fractionation called cooking with active oxygen and solid alkali (CAOSA), which could fractionate lignocellulose into its constituents while remaining in processable form. In the CAOSA approach, environmentally-friendly chemicals were applied instead of undesirable chemicals including strong alkalis and sulfides. Notably, the alkali recovery for this process promised to be relatively simple, neither causticizing nor sintering. These features made the CAOSA process an alternative for both lignocellulose fractionation and biomass pretreatment. Advantages and challenges have also been discussed in order to provide a comprehensive perspective with respect to existing strategies.
      PubDate: 2017-07-10T06:15:22.111817-05:
      DOI: 10.1002/cssc.201700906
       
  • Influence of the Water Phase State on the Thermodynamics of Aqueous Phase
           Reforming for Hydrogen Production
    • Authors: Séverine Le Gac; Renée M Ripken, Jan Meuldijk, Johannes G.E. Gardeniers
      Abstract: Abstract: Hydrogen is a promising renewable energy source that can be produced from biomass using Aqueous Phase Reforming (APR). Here, using data obtained from AspenPlus and the literature, we evaluated the phase state, temperature-dependent enthalpy, and Gibbs free energy for the APR of small biomass model substrates. Phase equilibrium studies reveal that, under typical APR reaction conditions, the reaction mixture is in the liquid phase. Therefore, we show for the first time that the water-gas-shift (WGS), which is the second main reaction of APR, must be modeled in the liquid phase, resulting in an endothermic instead of an exothermic enthalpy of reaction. A significant implication of this finding is that, although APR has been introduced as more energy saving than conventional reforming methods, the WGS in APR has a comparable energy demand to the WGS in steam reforming (SR).
      PubDate: 2017-07-10T04:15:42.924986-05:
      DOI: 10.1002/cssc.201700189
       
  • High Efficiency MAPbI3 Perovskite Solar Cell Using a Pure Thin Film of
           Polyoxometalate as Scaffold Layer
    • Authors: Mohammad Khaledi Sardashti; Mahmoud Zendehdel, Narges Yaghoobi Nia, Davud Karimian, Mohammad Sheikhi
      Abstract: In this work, we successfully used a pure layer of [SiW11O39]8- polyoxomethalate (POM) structure as a thin film scaffold layer of CH3NH3PbI3 based perovskite solar cells (PSCs). A smooth nanoporous surface of POM cause to amazing improvement of the photocurrent density, External Quantum Efficiency (EQE) and overall efficiency of the PSCs compare to mp-TiO2 as scaffold layer. Average PCE values of 15.5% with champion device as 16.3% could achieve by using POM and sequential deposition method of perovskite layer. Furthermore, modified and defect-free POM/perovskite interface led to elimination of the anomalous hysteresis in the current-voltage curves. Open-circuit voltage decay study show promising decrease of the electron recombination in the POM based PSCs which also related to modification of POM/perovskite interface and higher electron transport inside the POM layer.
      PubDate: 2017-07-07T23:25:56.281131-05:
      DOI: 10.1002/cssc.201701027
       
  • A comparative study of basic, amphoteric and acidic catalysts in the
           oxidative coupling of methanol and ethanol for acrolein production
    • Authors: Aleksandra Lilic; Tiantian Wei, Simona Bennici, Jean-François Devaux, Jean-Luc Dubois, Aline Auroux
      Abstract: The impact of acid/base properties (determined by adsorption microcalorimetry) of various catalysts on the cross-aldolization of acetaldehyde and formaldehyde leading to acrolein was methodically studied in oxidizing conditions starting from a mixture of methanol and ethanol. The aldol-condensation and further dehydration to acrolein were carried out on catalysts presenting various acid-base properties (MgO, Mg-Al, Mg-SiO2, NbP, and HPA-SiO2). Thermodynamic calculations revealed that cross-aldolization is always favored comparing to self-aldolization of acetaldehyde which leads to crotonaldehyde formation. The presence of strong basic sites is shown to be necessary, but a too high amount drastically increases COx production. On strong acid sites production of acrolein and carbon oxides (COx) does not increase with temperature. The optimal catalyst for this process should be amphoteric with a balanced acid-base cooperation of medium strength sites and a small amount (150 kJ mol-1).
      PubDate: 2017-07-07T09:21:27.141205-05:
      DOI: 10.1002/cssc.201701040
       
  • Concentration-gradient multi-channel flow stream membrane capacitive
           deionization cell for ultra-high desalination capacity of carbon
           electrodes
    • Authors: Choonsoo Kim; Juhan Lee, Pattarachai Srimuk, Mesut Aslan, Volker Presser
      Abstract: We present a novel multi-channel membrane flow stream capacitive deionization (MC-MCDI) concept with two flow streams to control the environment around the electrodes and a middle channel for water desalination. The introduction of side channels to our new cell design allows operation in a highly saline environment, while the feed water stream in the middle channel (conventional CDI channel) is separated from the electrodes with anion and cation exchange membranes. At a high salinity gradient between side (1000 mM) and middle (5 mM) channels, MC-MCDI exhibited an unprecedented salt adsorption capacity (SAC) of 56 mg/g in the middle channel with charge efficiency close to unity and low energy consumption. This excellent performance corresponds to a four-fold increase in desalination performance compared to the state-of-the-art in a conventional CDI cell. The enhancement originates from the enhanced specific capacitance in high molar saline media in agreement with the Gouy-Chapman-Stern theory and from a double ion desorption/adsorption process of MC-MCDI via voltage operation from -1.2 V to +1.2 V.
      PubDate: 2017-07-07T06:20:28.630583-05:
      DOI: 10.1002/cssc.201700967
       
  • Prospective Symbiosis of Green Chemistry and Energetic Materials
    • Authors: Ilya V. Kuchurov; Mikhail N. Zharkov, Leonid L. Fershtat, Nina N. Makhova, Sergei G. Zlotin
      Abstract: A global increase in the environmental pollution demands the development of new "cleaner" chemical processes. Among urgent improvements, replacement of traditional hydrocarbon-derived toxic organic solvents with neoteric solvents less harmful for the environment is one of the most vital issues. Due to favorable combination of unique properties, ionic liquids (ILs), dense gases, and supercritical fluids (SCFs) have gained considered attention as suitable green chemistry media for preparation and modification of important chemical compounds and materials. In particular, they have a significant potential in a specific and very important area of research which is associated with manufacturing and processing of high-energy materials (HEMs). These large-scale manufacturing processes, in which hazardous chemicals and extreme conditions are used, produce a huge amount of hard-to-dispose waste. Furthermore, they are risky to staff and any improvements that would reduce fire and explosion risks of the corresponding processes are highly desirable. In this review, useful applications of almost non-flammable ILs, dense gases, and SCFs (first of all, carbon dioxide) for nitration and other reactions used for manufacturing of HEMs are considered. Recent advances in the field of energetic (oxygen-balanced and hypergolic) ILs are summarized. A significant attention is paid to the SCF-based micronization techniques, which improve energetic performance of HEMs via an efficient control of morphology and particle size distribution of the HEMs fine particles, and to useful applications of SCFs in HEM processing which makes them less hazardous.
      PubDate: 2017-07-06T09:20:30.114555-05:
      DOI: 10.1002/cssc.201701053
       
  • Photovoltaic Rudorffites: Lead-Free Silver Bismuth Halides Alternative to
           Hybrid Lead Halide Perovskites
    • Authors: Ivan Turkevych; Said Kazaoui, Eisuke Ito, Toshiyuki Urano, Koji Yamada, Hiroshi Tomiyasu, Hideo Yamagishi, Michio Kondo, Shinji Aramaki
      Abstract: Hybrid CPbX3 (C: Cs, CH3NH3; X: Br, I) perovskites possess excellent photovoltaic properties but are highly toxic, which hinders their practical application. Unfortunately, all Pb-free alternatives based on Sn and Ge are extremely unstable. Although stable and non-toxic C2ABX6 double perovskites based on alternating corner-shared AX6 and BX6 octahedra (A=Ag, Cu; B=Bi, Sb) are possible, they have indirect and wide band gaps of over 2 eV. However, is it necessary to keep the corner-shared perovskite structure to retain good photovoltaic properties' Here, we demonstrate another family of photovoltaic halides based on edge-shared AX6 and BX6 octahedra with the general formula AaBbXx (x=a+3 b) such as Ag3BiI6, Ag2BiI5, AgBiI4, AgBi2I7. As perovskites were named after their prototype oxide CaTiO3 discovered by Lev Perovski, we propose to name these new ABX halides as rudorffites after Walter Rüdorff, who discovered their prototype oxide NaVO2. We studied structural and optoelectronic properties of several highly stable and promising Ag–Bi–I photovoltaic rudorffites that feature direct band gaps in the range of 1.79–1.83 eV and demonstrated a proof-of-concept FTO/c-m-TiO2/Ag3BiI6/PTAA/Au (FTO: fluorine-doped tin oxide, PTAA: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], c: compact, m: mesoporous) solar cell with photoconversion efficiency of 4.3 %.Move over perovskite: Optoelectronic properties of several highly stable silver iodobismuthates with rudorffite structure reveal them as alternative nontoxic and solution-processable photovoltaic materials that feature direct band gaps of around 1.8 eV. The proof-of-concept solar cell with FTO/c-m-TiO2/Ag3BiI6/PTAA/Au (c: compact; m: mesoporous; PTAA: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]) architecture shows a promising power conversion efficiency of 4.3 %.
      PubDate: 2017-07-06T05:35:41.090549-05:
      DOI: 10.1002/cssc.201700980
       
  • Efficient and Highly Selective Solvent-Free Oxidation of Primary Alcohols
           to Aldehydes Using Bucky Nanodiamond
    • Authors: Yangming Lin; Kuang-Hsu (Tim) Wu, Linhui Yu, Saskia Heumann, Dangsheng Su
      Abstract: Selective oxidation of alcohols to aldehydes is widely applicable to the synthesis of various green chemicals. The poor chemo-selectivity for complicated primary aldehydes over state-of-the-art metal-free or metal-based catalysts represents a major obstacle for industrial application. Here we report on bucky nanodiamond as a potential green catalyst which exhibits excellent chemo-selectivity and cycle stability in the selective oxidation of primary alcohols in diverse structures (22 examples, including aromatic, substituted aromatic, unsaturated, heterocycle and linear chain alcohols) to their corresponding aldehydes; the results are even comparable to the reported transition metal catalysts and conventional Pt/C and Ru/C catalysts for certain substrates under solvent-free conditions. The possible activation process of surface oxygen groups and defect species to oxidant and substrate are revealed with model catalysts, ex-situ electrochemical measurement and ex-situ attenuated total reflectance. The zigzag edges of sp2 carbon planes have been shown to play a key role in these reactions.
      PubDate: 2017-06-30T10:06:29.536421-05:
      DOI: 10.1002/cssc.201700968
       
  • Impact of macroporosity on catalytic upgrading of fast pyrolysis bio-oil
           by esterification over silica sulfonic acids
    • Authors: Jinesh Manayil; Amin Osatiashtiani, Alvaro Mendoza, Christopher Parlett, Lee Durndell, Mark Isaacs, Chrysoula Michailof, Eleni Heracleous, Angelos Lappas, Adam Lee, Karen Wilson
      Abstract: Fast pyrolysis bio-oils possess unfavourable physicochemical properties and poor stability, due in large part to the presence of carboxylic acids, which hinders their use as biofuels. Catalytic esterification offers an atom and energy efficient route to upgrade pyrolysis bio-oils. Propyl sulfonic acid silicas are active for carboxylic acid esterification but suffer mass-transport limitations for bulky substrates. Macropore (200 nm) incorporation enhances the activity of mesoporous SBA-15 architectures (post-functionalised by hydrothermal saline promoted grafting) for the esterification of linear carboxylic acids, with the magnitude of turnover frequency (TOF) enhancement increasing with chain length from 5 % (C3) to 110 % (C12). Macroporous-mesoporous PrSO3H/SBA-15 also offers a two-fold TOF enhancement over its mesoporous analogue for the esterification of a real thermal fast pyrolysis bio-oil derived from woodchips. The total acid number was reduced by 57 %, with GCxGC-ToFMS evidencing ester and ether formation accompanying loss of acid, phenolic, aldehyde and ketone components.
      PubDate: 2017-06-30T05:05:52.099639-05:
      DOI: 10.1002/cssc.201700959
       
  • Hierarchical Hollow Covalent Organic Frameworks-derived Heteroatom-doped
           Carbon Spheres for Metal-free Catalysis
    • Authors: Liuyi Li; Lu Li, Caiyan Cui, Hongjun Fan, Ruihu Wang
      Abstract: Covalent organic frameworks (COFs) with hollow structures hold great promises for developing new types of functional materials. Herein, we report a hollow spherical COF with a hierarchical shell, which serves as an effective precursor of B,N-codoped hierarchical hollow carbon spheres. Benefiting from the synergistic effect of hierarchical porosity, high surface area and B,N-codoping, the as-synthesized carbon spheres show the prospective utility as metal-free catalysts in nitroarene reduction. A mechanistic hypothesis is proposed based on theoretical and experimental studies. B atoms meta to pyridinic N atoms are identified to be the main catalytic active sites. The anti-aromaticity originated from the codoping of B and pyridinic N atoms, not charge distribution and deformation energy, is corroborated to play a pivotal role in the catalytic reaction.
      PubDate: 2017-06-29T22:07:51.523633-05:
      DOI: 10.1002/cssc.201700979
       
  • Tuning the composition of bimetallic electrodeposited Sn-Pb catalysts for
           enhanced activity and durability in CO2 electroreduction to formate
    • Authors: Elod Gyenge; Colin Moore
      Abstract: Bimetallic Sn-Pb catalysts with five different Sn:Pb atomic ratios were electrodeposited on teflonated carbon paper and un-teflonated carbon cloth using both fluoroborate and oxide containing deposition media to produce catalysts for electrochemical reduction of CO2 (ERC) to formate (HCOO-). The interaction between catalyst composition, morphology, substrate and deposition media was investigated by cyclic voltammetry and constant potential electrolysis at -2.0 V vs. Ag/AgCl for 2 h in 0.5 M KHCO3. The catalysts were analyzed before and after electrolysis with scanning electron microscopy (SEM) and X-ray diffraction (XRD) to determine the mechanisms of faradaic efficiency loss and degradation. Sn majority catalysts with 15 to 35%at. Pb generated faradaic efficiencies up to 95% with stable performance. Pure Sn catalysts on the other hand, in spite of high initial stage formate production rates, experienced extensive (up to 30%) decrease of the faradaic efficiency. XRD results demonstrated the presence of polycrystalline SnO2 after electrolysis using Sn-Pb catalysts with 35%at. Pb and its absence in case of pure Sn. It is proposed that the presence of Pb (15 to 35 %at.) in Sn majority catalysts stabilized SnO2, which is responsible for the enhanced faradaic efficiency and catalytic durability in ERC.
      PubDate: 2017-06-29T21:06:26.653377-05:
      DOI: 10.1002/cssc.201700761
       
  • Mechanochemical Ring-Opening Polymerization of Lactide: Liquid-Assisted
           Grinding for the Green Synthesis of Poly(lactic acid) with High Molecular
           Weight
    • Authors: Nuri Ohn; Jihoon Shin, Sung Sik Kim, Jeung Gon Kim
      Abstract: Mechanochemical polymerization of lactide is carried out by using ball milling. Mechanical energy from collisions between the balls and the vessel efficiently promotes an organic-base-mediated metal- and solvent-free solid-state polymerization. Investigation of the parameters of the ball-milling synthesis revealed that the degree of lactide ring-opening polymerization could be modulated by the ball-milling time, vibration frequency, mass of the ball media, and liquid-assisted grinding. Liquid-assisted grinding was found to be an especially important factor for achieving a high degree of mechanochemical polymerization. Although polymer-chain scission from the strong collision energy prevented mechanical-force-driven high-molecular-weight polymer synthesis, the addition of only a small amount of liquid enabled sufficient energy dissipation and poly(lactic acid) was thereby obtained with a molecular weight of over 1×105 g mol−1.The miller's tale: Mechanochemical polymerization of lactide is carried out by using ball milling. Mechanical energy from the collisions between the balls and the vessel efficiently promoted an organic-base-mediated metal- and solvent-free solid-state polymerization. Addition of a small amount of liquid enabled energy dissipation and poly(lactic acid) was thereby obtained with a molecular weight of over 1×105 g mol−1.
      PubDate: 2017-06-29T08:05:32.834139-05:
      DOI: 10.1002/cssc.201700873
       
  • Enhancing perovskite electrocatalysis of solid oxide cells through
           controlled growth of nanoparticles
    • Authors: Bin Hua; Meng Li, Yi-Fei Sun, Jian-Hui Li, Jing-Li Luo
      Abstract: Perovskite oxides have received a great deal of attentions as promising electrodes in both solid oxide fuel cells (SOFCs) and solid oxide electrolyzer cells (SOECs) because of their reasonable reactivity, impurity tolerance, tunable property, etc. Particular explorations are still required for advancing the perovskite electrodes, which normally suffer from slow kinetics in electrocatalysis. In the past decades, several experimental studies have developed new classes of perovskites with advanced characteristics and electrode kinetics at technical levels. In parallel with those developments, the achievements in theoretical and computational studies have led to substantial understanding, at the atomic level, of their physicochemical properties and electrocatalytic behaviors. The chemical and structural flexibilities enable the perovskites to accommodate most metallic elements without destroying their complex matrix structures, thereby delivering a pathway to engineering their catalytic properties. In this contribution, we briefly introduce the recent advances in perovskite electrodes, and focus on the perovskites with exsolved nanoparticles as the enhanced electrocatalytic materials.
      PubDate: 2017-06-24T01:47:27.982784-05:
      DOI: 10.1002/cssc.201700936
       
  • Molecular Self-Assembly Fabrication and Carrier Dynamics of Stable and
           Efficient CH3NH3Pb(1−x)SnxI3 Perovskite Solar Cells
    • Authors: Jiandong Fan; Chong Liu, Hongliang Li, Cuilin Zhang, Wenze Li, Yaohua Mai
      Abstract: The Sn-based perovskite solar cells (PSCs) provide the possibility that swaps the Pb element toward toxic-free PSCs. Here, we innovatively employed a molecular self-assembly approach to obtain a series CH3NH3Pb(1−x)SnxI3 (0≤x≤1) perovskite thin films with full coverage. The optimized planar CH3NH3Pb0.75Sn0.25I3 PSCs with inverted structure was consequently realized with a maximum power conversion efficiency (PCE) over 14 %, which displayed a stabilized power output (SPO) over 12 % within 200 s at 0.6 V forward bias. Afterward, we investigated the factors that limited the efficiency improvement of hybrid Sn-Pb PSCs, and analyzed the possible reason of the hysteresis effect occurred even in the inverted structure cell. Particularly, the oxidation of hybrid Sn-Pb perovskite thin film was demonstrated to be the main reason that caused the decreasing of minority-carrier lifetime, which quenched the carrier collection efficiency while the depletion layer was widened. The imbalance of charge transport was intensified that was associated with the increased hole defect-state density and decreased the electron defect-state density after Sn was introduced. This study is benefit to tackle the intractable issue regarding the toxic Pb in perovskite devices and step forward toward realizing the lead-free PSCs with high stability and efficiency.
      PubDate: 2017-06-22T20:51:01.167451-05:
      DOI: 10.1002/cssc.201700880
       
  • Nanoelectrical and Nanoelectrochemical Imaging of Pt/p-Si and Pt/p+-Si
           Electrodes
    • Authors: Jingjing Jiang; Zhuangqun Huang, Chengxiang Xiang, Rakesh Poddar, Hans-Joachim Lewerenz, Kimberly M. Papadantonakis, Nathan Lewis, Bruce Brunschwig
      Abstract: The interfacial properties of electrolessly deposited Pt nanoparticles (Pt-NP) on p-Si and p+-Si electrodes have been resolved on the nanometer scale using a combination of scanning probe methods. Atomic-force microscopy (AFM) showed highly dispersed Pt nanoparticles. Conductive AFM measurements showed that only about half of the particles exhibited measurable contact currents, with a factor of 10^3 difference in current. Local current-voltage measurements revealed a rectifying junction with a resistance of ≥ 10 MΩ at the Pt-NP/p-Si interface, while Pt-NP/p+-Si samples formed an Ohmic junction with a local resistance of ≥ 1 MΩ. The particles were strongly attached to the sample surface in air. However in contact with an electrolyte, the adhesion of the particles to the surface was substantially lower. Scanning electrochemical microscopy (SECM) showed smaller, but more uniform electrochemical currents for the particles relative to the currents observed in conductive AFM measurements. In accord with the conductive AFM measurements, SECM measurements showed conductance through the substrate for only a minority of the particles. These results suggest that the electrochemical performance of the electrolessly deposited Pt nanoparticles on Si is ascribable to: 1) the high resistance of the contact between the particles and the substrate; 2) the low (
      PubDate: 2017-06-21T12:45:47.696481-05:
      DOI: 10.1002/cssc.201700893
       
  • Co-based Active Species Molecularly Immobilized on Carbon Nanotubes for
           Oxygen Reduction Reaction
    • Authors: Sujin Kim; Dawoon Jang, Joonwon Lim, Junghoon Oh, Sang Ouk Kim, Sungjin Park
      Abstract: Hybrid systems that molecule-based active species are combined with nanoscale materials may offer valuable routes to enhance the catalytic performances for electrocatalytic reactions. Development of rationally designed, cost-effective efficient catalysts for oxygen reduction reaction (ORR) is a crucial challenge for fuel cell and metal-air battery applications. In this work, we report a novel hybrid ORR catalyst material synthesized by a well-defined reaction pathway between Co-based organometallic molecules and N-doped multiwalled carbon nanotubes (MWCNT) at room temperature. The hybrid ORR catalyst shows excellent catalytic performances with an onset potential of 0.95 V (vs. RHE), superior durability and good methanol tolerance. Chemical and structural characterizations reveal that Co-based organometallic molecules maintained the original structure of Co(acetylacetonate)2 after prolonged cycles of reaction, while coordinated to heteroatoms of MWCNT. Thorough electrochemical investigation suggests that the major catalytic active site is Co-O4-NCNT.
      PubDate: 2017-06-18T21:21:58.068842-05:
      DOI: 10.1002/cssc.201701038
       
  • Sustainable separations of C4 hydrocarbons using microporous materials
    • Authors: Stefania Tanase-Grecea; Mascha Gehre, Zhiyong Guo, Gadi Rothenberg
      Abstract: Petrochemical refineries must separate hydrocarbons mixtures on a large scale for the production of fuels and chemicals. Most often, these hydrocarbons are separated by distillation, which is extremely energy-intensive. This high energy cost can be mitigated by developing materials that can enable efficient adsorptive separation. In this critical review, we first outline the principles of adsorptive separation. We then examine the case for C4 separations using zeolites and metal-organic frameworks (MOFs). By analysing both experimental and theoretical studies, we outline the challenges and opportunities in C4 separation, with a focus on the separation mechanisms and structure-selectivity correlations. Zeolites are commonly used as adsorbents, and in some cases can separate C4 mixtures well. The pore sizes of 8-membered-ring zeolites, for example, are in the order of the kinetic diameters of C4 isomers. Although zeolites have the advantage of a rigid and highly stable structure, this is often difficult to functionalize. MOFs are attractive candidates for hydrocarbon separation because their pores can be tailored to optimize the adsorbate-adsorbent interactions. MOF-5 and ZIF-7 show promising results in separating all C4 isomers, but breakthrough experiments under industrial conditions are needed to confirm these results. Moreover, the flexibility of the MOF structures could hamper their application under industrial conditions. All in all, adsorptive separation is a promising viable alternative, and it is likely to play an increasingly important role in tomorrow's refineries.
      PubDate: 2017-06-15T21:20:27.077112-05:
      DOI: 10.1002/cssc.201700657
       
  • High-Efficiency Perovskite Solar Cell Based on Poly(3-Hexylthiophene):
           Influence of Molecular Weight and Mesoscopic Scaffold Layer
    • Authors: Narges Yaghoobi Nia; Fabio Matteocci, Lucio Cina, Aldo Di Carlo
      Abstract: Here, we investigated the effect of the molecular weight (MW) of poly 3-hexylthiophene (P3HT) hole-transport material on the performance of perovskite solar cells (PSCs). We found that by increasing the MW the photovoltaic performances of the cells are enhanced leading to an improvement of the overall efficiency. P3HT-based PSCs with a MW of 124 kDa can achieve an overall average efficiency of 16.2 %, double with respect to the ones with a MW of 44 kDa. Opposite to spiro-OMeTAD-based PSCs, the photovoltaic parameters of the P3HT-based devices are enhanced by increasing the mesoporous TiO2 layer thickness from 250 to 500 nm. Moreover, for a titania scaffold layer thickness of 500 nm, the efficiency of P3HT-based PSCs with high MW is larger than the spiro-OMeTAD based PSCs with the same scaffold layer thickness. Recombination reactions of the devices were also investigated by voltage decay and electrochemical impedance spectroscopy. We found that the relationship between P3HT MW and cell performance is related to the reduction of charge recombination and to the increase of the P3HT light absorption by increasing the MW.Molecular weight matters! High efficiency perovskite solar cells fabricated in ambient conditions by controlling of mesoporous (mp)-TiO2 thickness and investigation of poly(3-hexylthiophene) (P3HT) molecular weight (MW) as hole-transport layer. The best efficiencies are achieved for a MW of 124 kDa and for a thickness of mp-TiO2 of 500 nm. Efficiency enhancement is mainly related to the increase of Jsc and FF as P3HT MW increases.
      PubDate: 2017-06-14T15:31:37.454372-05:
      DOI: 10.1002/cssc.201700635
       
  • Stable Organic Radicals in Lignin; A Review
    • Authors: Dimitris Argyropoulos; Shradha S Patil
      Abstract: Lignin and the quest for the origin of stable organic radicals in it have seen numerous developments. Although there have been various speculations over the years on the formation of these stable radicals, researchers have not been to arrive at a solid, unequivocal hypothesis that applies to all treatments and types of lignin. The extreme complexity of lignin and its highly aromatic, crosslinked, branched and rigid structure has made such efforts rather cumbersome. Since the early fifties, researchers in this field have dedicated their efforts to establish methods for the detection and determination of spin content, theoretical simulations, and reactions on model compounds and spin trapping studies. While a significant amount of published research is available on lignin or its model compounds and the reactive intermediates involved during various chemical treatments (pulping, bleaching, extractions, chemical modifications, etc.) the literature provides a limited view on the origin, nature, and stability of such radicals. Consequently, this review is focused on examining the origin of such species in lignin, factors affecting their presence, reactions involved in their formation, and methods for their detection.
      PubDate: 2017-06-12T07:15:20.852255-05:
      DOI: 10.1002/cssc.201700869
       
  • Boosting the supercapacitance of nitrogen-doped carbon by tuning surface
           functionalities
    • Authors: Jasper Biemolt; Ilse M. Denekamp, Thierry K. Slot, Gadi Rothenberg, David Eisenberg
      Abstract: We report that the specific capacitance of a highly porous, nitrogen-doped carbon is nearly tripled by orthogonal optimization of microstructure and surface chemistry. First, the carbons' hierarchical pore structure and specific surface area were tweaked by controlling the temperature and sequence of thermal treatments. The best process (pyrolysis at 900 °C, washing, and a second annealing at 1000 °C) yielded carbons with a specific capacitance of 117 F/g - nearly double that of a carbon made by a typical, single-step synthesis at 700 °C. Following the structural optimization, the surface chemistry of the carbons was enriched by applying an oxidation routine based on nitric and sulfuric acids in 1:4 ratio, at two different treatment temperatures (0 °C and 20 °C) and along different treatment times. The optimal treatment times are 4 h at 0 °C and only 1 h at 20 °C. Overall, specific capacitance nearly tripled relative to the original carbon, reaching to 168 F/g. The inherent nitrogen doping of the carbon comes into interplay with the acid-induced surface functionalization, creating a mixture of oxygen- and nitrogen-oxygen functionalities. The evolution of surface chemistry was carefully followed by X-ray photoelectron spectroscopy and by N2 sorption porometry, revealing stepwise surface functionalization and simultaneous carbon etching. Overall, these processes are responsible for the peak-shaped capacitance trends in the carbons.
      PubDate: 2017-06-06T10:15:21.602775-05:
      DOI: 10.1002/cssc.201700902
       
  • Ionic-Liquid-Assisted Microwave Synthesis of Solid Solutions of
           Sr1−xBaxSnO3 Perovskite for Photocatalytic Applications
    • Authors: Tarek Alammar; Igor I. Slowing, Jim Anderegg, Anja-Verena Mudring
      Pages: 3387 - 3401
      Abstract: Nanocrystalline Sr1−xBaxSnO3 (x=0, 0.2, 0.4, 0.8, 1) perovskite photocatalysts were prepared by microwave synthesis in an ionic liquid (IL) and subsequent heat-treatment. The influence of the Sr/Ba substitution on the structure, crystallization, morphology, and photocatalytic efficiency was investigated and the samples were fully characterized. On the basis of X-ray diffraction results, as the Ba content in the SrSnO3 lattice increases, a symmetry increase was observed from the orthorhombic perovskite structure for SrSnO3 to the cubic BaSnO3 structure. The analysis of the sample morphology by SEM reveals that the Sr1−xBaxSnO3 samples favor the formation of nanorods (500 nm–5 μm in diameter and several micrometers long). The photophysical properties were examined by UV/Vis diffuse reflectance spectroscopy. The band gap decreases from 3.85 to 3.19 eV with increasing Ba2+ content. Furthermore, the photocatalytic properties were evaluated for the hydroxylation of terephthalic acid (TA). The order of the activities for TA hydroxylation was Sr0.8Ba0.2SnO3>SrSnO3>BaSnO3>Sr0.6Ba0.4SnO3>Sr0.2Ba0.8SnO3. The highest photocatalytic activity was observed for Sr0.8Ba0.2SnO3, and this can be attributed to the synergistic impacts of the modification of the crystal structure and morphology, the relatively large surface area associated with the small crystallite size, and the suitable band gap and band-edge position.Raising the barium: A sustainable procedure for the preparation of Sr1−xBaxSnO3 perovskites for photo-catalytic applications through microwave irradiation in an ionic liquid as a microwave absorbing agent, green solvent, and capping agent is presented.
      PubDate: 2017-07-17T06:45:45.444968-05:
      DOI: 10.1002/cssc.201700615
       
 
 
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