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  Subjects -> COMPUTER SCIENCE (Total: 1969 journals)
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COMPUTER SCIENCE (1147 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: 11)
Abakós     Open Access   (Followers: 3)
Academy of Information and Management Sciences Journal     Full-text available via subscription   (Followers: 67)
ACM Computing Surveys     Hybrid Journal   (Followers: 23)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 4)
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: 12)
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: 19)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 9)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 4)
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: 10)
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: 10)
Advanced Engineering Materials     Hybrid Journal   (Followers: 24)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 14)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
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: 3)
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: 9)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
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: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access  
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: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 6)
American Journal of Sensor Technology     Open Access   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 5)
Analysis in Theory and Applications     Hybrid Journal  
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
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: 13)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 1)
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: 31)
Applied Medical Informatics     Open Access   (Followers: 9)
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: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 5)
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: 8)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Basin Research     Hybrid Journal   (Followers: 3)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Bioinformatics     Hybrid Journal   (Followers: 233)
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: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 119)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 12)
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)
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: 13)
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: 18)
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: 47)
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  
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 1)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 8)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 12)
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: 27)
Computer     Full-text available via subscription   (Followers: 78)
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: 8)
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: 13)
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: 10)
Computer Science Education     Hybrid Journal   (Followers: 12)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Master Research     Open Access   (Followers: 9)
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  [1583 journals]
  • Mapping the free energy of lithium solvation in the protic ionic liquid
           Ethylammonuim Nitrate: A metadynamics study
    • Authors: Ali Kachmar; Marcelo Carignano, Teodoro Laino, Marcella Iannuzzi, Jürg Hutter
      Abstract: The understanding of lithium solvation and transport in ionic liquids is important due to the possible applications in electrochemical devices. Using first principles simulations aided with the metadynamics approach we study the free energy landscape for lithium at infinite dilution conditions in ethylammonium nitrate, a protic ionic liquid. We analyze the local structure of the liquid around the lithium cation and find a quantitative picture in agreement with experimental findings. Our simulations show that the lowest two free energy minima correspond to conformations with the lithium solvated either by 3 or 4 nitrates ions with a transition barrier between them of 0.2 eV. Other less probable conformations having a different solvation pattern are also investigated.
      PubDate: 2017-05-26T00:25:29.763862-05:
      DOI: 10.1002/cssc.201700510
       
  • Metal-organic Compound Branched MoS2 for Achieving High Performance
           Perovskite Solar cells
    • Authors: Ruina Dai; Yangyang Wang, Jie Wang, Xianyu Deng
      Abstract: MoS2 as a graphene-like 2D material shows a large potential to replace even overcome graphene in various important applications due to its perfect properties of electrical, optical, frictional, and tunable band gap. However, low solubility in the most of common solvents makes it difficult to prepare via a simple solution process. Here we introduce a metalorganic compound to modify MoS2. Phenyl acetylene silver (PAS) functionalized MoS2 compound is easily dispersed in the solvent of DMF and water. A conductive polymer PEDOT: PSS blend with the MoS2 leads to a significant enhancement of the performance of planar heterojunction perovskite solar cells. The solar cells have a high power conversion efficiency of 16.47% as well as largely increased stability. This provides a feasible method on large-scale yield of the MoS2 for wide applications in various electric devices.
      PubDate: 2017-05-25T21:20:28.148643-05:
      DOI: 10.1002/cssc.201700603
       
  • Brownmillerite-type Ca2FeCoO5 as a Practicable Oxygen Evolution Reaction
           Catalyst
    • Authors: Etsushi Tsuji; Teruki Motohashi, Hiroyuki Noda, Damian Kowalski, Yoshitaka Aoki, Hajime Tanida, Junji Niikura, Yukinori Koyama, Masahiro Mori, Hajime Arai, Tsutomu Ioroi, Naoko Fujiwara, Yoshiharu Uchimoto, Zempachi Ogumi, Hiroki Habazaki
      Abstract: Here, we report remarkable oxygen evolution reaction (OER) catalytic activity of brownmillerite (BM)-type Ca2FeCoO5. The OER activity of this oxide is comparable to or beyond those of the state-of-the-art perovskite (PV)-catalyst Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and a precious-metal catalyst RuO2, emphasizing the importance of the characteristic BM structure with multiple coordination environments of transition metal (TM) species. Also, Ca2FeCoO5 is obviously advantageous in terms of expense/laboriousness of the material synthesis. These facts make this oxide a promising OER catalyst used in many energy conversion technologies such as metal-air secondary batteries and hydrogen production from electrochemical/photocatalytic water splitting.
      PubDate: 2017-05-25T00:20:22.793569-05:
      DOI: 10.1002/cssc.201700499
       
  • Understanding the limiting factors of solvent annealed Small molecule bulk
           heterojunction organic solar cells from a chemical perspective
    • Authors: Aurelien Viterisi; Daniel Fernandez, Vijay Kumar Challuri, James william Ryan, Eugenia Martinez-Ferrero, Francesc Guispert-Guirado, Marta Martinez, Eduardo Escudero, Caterina Stenta, Lluis Francisco Marsal, Emilio Palomares
      Abstract: A detailed account on the limiting factors of solvent annealed bulk-heterojunction small molecule organic solars cell is given. This account is based on the extensive characterization of solar cell devices made from a library of five diketopyrolopyrole (DPP) donor dyes. Their chemical structure is designed in such a way as to provide insights on the energetics of solar cell active layer microstructure formation. Numerous chemical and physical properties of the active layers are assessed and interrelated such as light absorption, molecular packing in the solid state, crystal-forming properties in thin films, charge carrier mobility and charge carrier recombination kinetics. A myriad of characterization techniques are used such as UV-Vis absorption, photoluminescence, X-ray diffraction (XRD), AFM, photo-induced transient measurements which provide information on optical properties of the active layers, morphology and recombination kinetics. Consequently, a mechanism for the solvent vapour annealing-assisted formation of crystalline domains of donor molecules in the active layer is proposed, and the microstructure features are related to the J-V characteristics of the devices. According to this model, the crystalline phase in which the donor crystallize in the active layer is the key determinant in directing the formation of the microstructure.
      PubDate: 2017-05-24T10:20:27.604284-05:
      DOI: 10.1002/cssc.201700440
       
  • A strategy to enhance the efficiency of quantum dot sensitized solar cells
           by decreasing the electron recombinations with polyoxometalate/TiO2 as the
           electronic interface layer
    • Authors: Li Chen; Wei-Lin Chen, Jian-Ping Li, Jia-Bo Wang, En-Bo Wang
      Abstract: The serious electron recombination occurring in TiO2/quantum dot sensitizer/electrolyte interface is the key reason for hindering the further efficiency improvement of QDSCs. Polyoxometalate(POM) can be as electron transfer media to decreasing electron recombination of photoelectric device, which is due to the excellent oxidation reduction properties and thermostability. So in this paper, POM/TiO2 electronic interface layer prepared by a simple layer-by-layer self-assembly method is added between FTO and mesoporous TiO2 in the photoanode of the QDSCs, and their effects on the photovoltaic performance are systematically investigated. The photovoltaic experimental results and electron transmission mechanism explanation show that POM/TiO2 electronic interface layer in the QDSCs can obviously suppress the electron recombinations, increase the electron lifetime and result in smoother electron transmission. In summary, the best conversion efficiency of QDSCs with POM/TiO2 electronic interface layers are increased to 8.02%, which are improved by 25.1% compared to the QDSCs without POM/TiO2. This work firstly builds an electron transfer bridge between FTO and quantum dot sensitizer and paves the way for the further efficiency improvement of QDSCs.
      PubDate: 2017-05-23T06:21:17.858876-05:
      DOI: 10.1002/cssc.201700764
       
  • Amphoteric ion-exchange membranes with significantly improved vanadium
           barrier properties for all-vanadium redox flow batteries.
    • Authors: Olga Nibel; Tomasz Rojek, Thomas J. Schmidt, Lorenz Gubler
      Abstract: All-vanadium redox flow batteries (VRBs) have attracted considerable interest as promising energy storage devices which can allow the efficient utilization of renewable energy sources. The membrane, which separates the porous electrodes in a redox flow cell, is one of the key components in VRBs. High rates of cross-over of vanadium ions and water through the membrane impair the efficiency and capacity of a VRB. Thus, membranes with low permeation rate of vanadium species and water are required, also characterized by low resistance and stability in the VRB environment. Here, we present a new design concept for amphoteric ion exchange membranes, based on radiation-induced grafting of vinylpyridine into an ethylene-tetrafluoroethylene base film and a two-step functionalization to introduce cationic and anionic exchange sites, respectively. During long-term cycling, redox flow cells containing these membranes showed higher efficiency, less pronounced electrolyte imbalance and significantly reduced capacity decay compared to the cells with the benchmark material Nafion® 117 and 212.
      PubDate: 2017-05-23T04:20:22.556256-05:
      DOI: 10.1002/cssc.201700610
       
  • A robust, water-based, functional binder framework for high energy
           lithium-sulfur batteries
    • Authors: Matthew James Lacey; Viking Österlund, Fabian Jeschull, Andreas Bergfelt, Tim Bowden, Daniel Brandell
      Abstract: We report here a water-based functional binder framework for the lithium-sulfur battery system, based on the general combination of a polyether and an amide-containing polymer. These binders are applied here to positive electrodes optimised towards high energy electrochemical performance based only on commercially available materials. Electrodes with up to 4 mAh cm-2 capacity and 97 - 98% coulombic efficiency are achievable in electrodes with a 65% total sulfur content and a poly(ethylene oxide):poly(vinylpyrrolidone) (PEO:PVP) binder system. Exchange of either binder component for a different polymer with similar functionality preserves the high capacity and coulombic efficiency. The improvement in coulombic efficiency from the inclusion of the coordinating amide group was also observed in electrodes where pyrrolidone moieties were covalently grafted to the carbon black, indicating the role of this functionality in facilitating polysulfide adsorption to the electrode surface. Mechanical properties of the electrodes appear not to significantly influence sulfur utilisation or coulombic efficiency in the short term but rather determine retention of these properties over extended cycling. These results demonstrate the robustness of this very straightforward approach, as well as the considerable scope for designing binder materials with targeted properties.
      PubDate: 2017-05-19T08:01:25.060212-05:
      DOI: 10.1002/cssc.201700743
       
  • Asymmetric supercapacitors based on rGO-PMo12 as a positive and rGO-PW12
           as a negative electrode
    • Authors: Deepak Dubal; Nilesh Chodankar, Ajayan Vinu, Do-Heyoung Kim, Pedro Gomez-Romero
      Abstract: Nanofabrication via "bottom-up" approach of hybrid electrode materials into well-defined architecture is essential for the next generation miniaturized energy storage devices. This paper describes the design and fabrication of reduced graphene oxide (rGO)/polyoxometalates (POMs) based hybrid electrode materials and their successful exploitation for asymmetric supercapacitor. Firstly, the redox active nanoclusters of POMs (phosphomolybdic acid (PMo12) and phosphotungstic acid (PW12)) are uniformly decorated on the surface of rGO nanosheets to take full advantage of both charge-storing mechanisms (faradaic from POMs and electric double layer from rGO). The as-synthesized rGO-PMo12 and rGO-PW12 hybrid electrodes exhibits great electrochemical performances with specific capacitance of 299 F/g (269 mF/cm2) and 370 F/g (369 mF/cm2) in 1 M H2SO4 electrolyte at 5 mA/cm2, respectively. Later, asymmetric supercapacitors was fabricated using rGO-PMo12 as a positive and rGO-PW12 as negative electrodes. This novel rGO-PMo12//rGO-PW12 asymmetric cell could be successfully cycled in a wide voltage window up to 1.6 V and hence exhibits excellent energy density of 39 Wh/kg (1.3 mWh/cm3) at a power density of 658 W/kg (23 mW/cm3).
      PubDate: 2017-05-18T23:06:59.585373-05:
      DOI: 10.1002/cssc.201700792
       
  • Organocatalytic Chemoselective Primary Alcohol Oxidation and Subsequent
           Cleavage of Lignin Model Compounds and Lignin
    • Authors: Saumya Dabral; Jose Hernández, Paul Kamer, Carsten Bolm
      Abstract: A one-pot two-step degradation of lignin β-O-4 model compounds initiated by preferred oxidation of the primary over the secondary hydroxyl groups with a TEMPO/DAIB system has been developed. The oxidised products are then cleaved by proline-catalysed retro-aldol reactions. This degradation methodology produces simple aromatics in good yields from lignin model compounds at room temperature with an extension to organosolv beechwood lignin L1 resulting in known cleavage products.
      PubDate: 2017-05-18T20:50:23.18525-05:0
      DOI: 10.1002/cssc.201700703
       
  • Environmentally friendly recycling of fuel cell's membrane electrode
           assembly using ionic liquids
    • Authors: Sophie Legeai; Maxime Balva, Nathalie Leclerc, Emmanuel Billy, Eric Meux
      Abstract: The platinum nanoparticles used as catalyst in Proton Exchange Membrane Fuel Cells (PEMFCs) could represent around 46 % of the total price of the cells1 for a large scale production which is one of the limitation of their commercialization. The recycling of this platinum catalyst can then be the best alternative to limit the production cost of PEMFCs. Usual recovery routes for spent catalysts containing platinum are pyro-hydrometallurgical processes in which a calcination step is followed by aqua regia treatment, generating fumes and NOx emission, respectively. An electrochemical recovery route is proposed here, more environmentally friendly, performed in "soft" temperature conditions and without any gases emission. It consists in the coupling of electrochemical leaching of platinum in chloride-based ionic liquids (ILs), followed by its electrodeposition. The leaching of platinum was studied in pure ionic liquids and in ionic liquids melts, at different temperatures and chloride contents. By modulating the composition of the ionic liquid melts, it is further possible to leach and electrodeposit the platinum from fuel cell electrodes in a single cell process, under inert or ambient atmosphere.
      PubDate: 2017-05-18T08:45:24.63433-05:0
      DOI: 10.1002/cssc.201700456
       
  • Dopant-Free Hole Transport Materials based on Methoxytriphenylamine
           Substituted Indacenodithienothiophene for Solution Processed Perovskite
           Solar Cells
    • Authors: Xiaoyuan Liu; Xiaolu Zheng, Yulong Wang, Zhiliang Chen, Fang Yao, Qi Zhang, Guojia Fang, Zhi-Kuan Chen, Wei Huang, ZongXiang Xu
      Abstract: Solution-processed hole transporting materials (HTMs) that are dopant-free show promise for use in low-cost, high performance perovskite solar cells (PSCs). The highest efficiency PSCs use organic HTMs, many of which have low mobilities and so require doping, which lowers the device stability. Additionally, these materials are not easily scaled because they often require complicated synthesis. Two novel HTMs (IDT-TPA and IDTT-TPA) were synthesized, which contained either an extended fused-ring indacenodithiophene (IDT) or indacenodithienothiophene (IDTT) core and strong electron donating methoxytriphenylamine (TPA) groups as the end-capping units. The extended conjugation in the backbone of IDTT-TPA resulted in stronger π-π interactions (3.321 Å) and a higher hole mobility of 6.46 × 10−4 cm2 V−1 s−1 when compared with that of IDT-TPA (9.53 × 10−5 cm2 V−1 s−1). A dopant free, planar PSC that contained IDTT-TPA was fabricated and exhibited a high power conversion efficiency (PCE) of 15.7%. This cell exhibited a higher PCE and less hysteresis than devices that contained IDT-TPA.
      PubDate: 2017-05-18T05:35:35.627593-05:
      DOI: 10.1002/cssc.201700197
       
  • Towards Long-Term Stable and Efficient Large-Area Organic Solar Cells
    • Authors: Pei-Ting Tsai; Kuan-Chu Lin, Cheng-Yu Wu, Chung-Hung Liao, Man-Chun Lin, Ying Qian Wong, Hsin-Fei Meng, Chih-Yu Chang, Chien-Lung Wang, Yi-Fan Huang, Sheng-Fu Horng, Hsiao-Wen Zan, Yu-Chiang Chao
      Abstract: In this study, we report that long-term stable and efficient organic solar cells (OSCs) can be obtained via the following strategies: (1) combination of rapid-drying blade-coating deposition with an appropriate thermal annealing treatment to obtain an optimized morphology of the active layer; (2) insertion of interfacial layers to optimize the interfacial properties. The resulting devices based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PBDTTT-EFT):[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) blend as the active layer exhibits a power conversion efficiency (PCE) up to 9.57%, which represents the highest efficiency ever reported for blade-coated OSCs. Importantly, the conventional structure devices based on poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blend can retain ~65% of their initial PCE for almost 2 years under operating conditions, which is the best result ever reported for long-term stable OSCs under operational conditions. More encouragingly, long-term stable large-area OSCs (active area = 216 cm2) based on P3HT:PCBM blend are also demonstrated. Our findings represent an important step toward the development of large-area OSCs with high performance and long-term stability.
      PubDate: 2017-05-17T22:00:32.688697-05:
      DOI: 10.1002/cssc.201700601
       
  • Reactive Precipitation of Anhydrous Alkali Sulfide Nanocrystals with
           Concomitant Abatement of Hydrogen Sulfide and co-Generation of Hydrogen
    • Authors: Yongan Yang; Xuemin Li, Yangzhi Zhao, Alice Brennan, Miranda McCeig, Colin A. Wolden
      Abstract: Anhydrous alkali sulfide (M2S, M = Li and Na) nanocrystals (NCs) are important materials central to the development of next generation cathodes and solid state electrolytes for advanced batteries, but not commercially available at present. This work reports an innovative method to directly synthesize M2S-NCs through alcohol-mediated reactions between alkali metals and hydrogen sulfide (H2S). In the first step, the alkali metal is complexed with alcohol in solution, forming metal alkoxide (ROM) and releasing hydrogen (H2). Next, H2S is bubbled through the ROM solution, where both chemicals are completely consumed to produce phase-pure M2S-NC precipitates and regenerate alcohol that can be recycled. The M2S-NC morphology may be tuned through choice of the alcohol and the solvent. Both synthetic steps are thermodynamically favorable (∆Gmo < -100 kJ/mol), proceeding rapidly to completion at ambient temperature with ~100% atom efficiency. The net result, H2S + 2M -> M2S + H2, makes good use of a hazardous chemical H2S and delivers two value-added products that naturally phase separate for easy recovery. This scalable approach provides an energy-efficient and environmentally-benign solution to the production of nanostructured materials required in emerging battery technologies.
      PubDate: 2017-05-16T10:45:29.314435-05:
      DOI: 10.1002/cssc.201700532
       
  • Reply to Comment on “Flexible Asymmetric Supercapacitors Based on
           Nitrogen-Doped Graphene Hydrogels with Embedded Nickel Hydroxide
           Nanoplates”
    • Authors: Shaochun Tang; Dongdong Li, Xiangkang Meng
      Abstract: In this reply to the Comment by Dr. Sascha Vongehr, the other authors of “Flexible Asymmetric Supercapacitors Based on Nitrogen-Doped Graphene Hydrogels with Embedded Nickel Hydroxide Nanoplates” present a rebuttal and clarify their interpretations of the issues he raised, arguing that numerous surmises and misinterpretations were made in the previous Comment.
      PubDate: 2017-05-12T02:45:33.137376-05:
      DOI: 10.1002/cssc.201700445
       
  • Direct Access to Primary Amines and Particle Morphology Control in
           Nanoporous CO2 Sorbents
    • Authors: Nesibe A. Dogan; Ercan Ozdemir, Cafer T. Yavuz
      Abstract: The Back Cover picture shows a nanoporous network with pendant nitrile groups and microsphere morphology. These microspheres are easily decorated with primary amines through in situ reduction by widely available boranes, and their surface area can easily be tuned. These structures can be used as sorbents for CO2 capture applications, such as those with fluidized beds requiring spheres of micron sizes. More details can be found in the Communication by Dogan et al. (
      DOI : 10.1002/cssc.201700190).
      PubDate: 2017-05-11T06:25:54.728044-05:
       
  • Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells
    • Authors: Yinshi Li; Xianda Sun, Ying Feng
      Abstract: The Inside Back Cover picture shows a promising high-temperature alkaline direct formate fuel cell operated in the absence of added hydroxide. The feasibility of the hydroxide self-feeding high-temperature alkaline direct formate fuel cell is mainly attributed to the hydrolysis of formate that provides enough OH− ions for the formate oxidation reaction. More details can be found in the Communication by Li et al. (
      DOI : 10.1002/cssc.201700228).
      PubDate: 2017-05-11T06:25:53.7274-05:00
       
  • Reliable Performance Characterization of Mediated Photocatalytic
           Water-Splitting Half Reactions
    • Authors: Lihao Han; Meng Lin, Sophia Haussener
      Abstract: The Inside Cover picture shows the solar-driven production of oxygen, protons, and iron(II) ions from the oxidation of water and reduction of iron(III) ions at catalyst-covered semiconductor particles. These are half-reactions necessary for the overall photo-driven water splitting in a dual-bed particle-suspension reactor. We quantified the reaction conversion by analyzing the gaseous and liquid products at a high temporal resolution. Comparing different methods provides us with a reliable and reproducible methodology for the accurate characterization of these photocatalytic (half-) reactions. More details can be found in the Full Paper by Han et al. (
      DOI : 10.1002/cssc.201601901).
      PubDate: 2017-05-11T06:25:51.049189-05:
       
  • Nitrogen Fixation by Gliding Arc Plasma: Better Insight by Chemical
           Kinetics Modelling
    • Authors: Weizong Wang; Bhaskar Patil, Stjin Heijkers, Volker Hessel, Annemie Bogaerts
      Abstract: Invited for this month's cover is the group of Prof. Dr. Annemie Bogaerts at the University of Antwerp and their collaborators at Eindhoven University of Technology in the laboratory of Prof. Dr. Volker Hessel. The cover image shows that gliding arc plasma leads to energy efficient nitrogen fixation by promoting the vibrational excitation of N2. The Full Paper itself is available at 10.1002/cssc.201700095.“We wanted to elucidate the plasma chemistry…” 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.201700095. View the Front Cover here: 10.1002/cssc.201700563.
      PubDate: 2017-05-11T06:25:45.309799-05:
      DOI: 10.1002/cssc.201700611
       
  • Nitrogen Fixation by Gliding Arc Plasma: Better Insight by Chemical
           Kinetics Modelling
    • Authors: Weizong Wang; Bhaskar Patil, Stjin Heijkers, Volker Hessel, Annemie Bogaerts
      Abstract: The Cover picture shows a gliding arc plasma that promotes the vibrational excitation of N2, which contributes significantly to activating the N2 molecules and overcoming the very high reaction energy barrier during the nitrogen fixation processes, and leads to an energy efficient way of nitric oxide production using air as a raw material. This helps to realize more realistic scenarios of entering a cutting-edge innovation in new business cases for the decentralized production of fertilizers for agriculture using renewable energy sources (solar/wind), in which low-temperature plasma technology might play an important role. More details can be found in the Full Paper by Wang et al. (
      DOI : 10.1002/cssc.201700095).
      PubDate: 2017-05-11T06:25:42.760271-05:
       
  • Nature-inspired Synthesis of Nanostructured Electrocatalysts through
           Mineralization of Calcium Carbonate
    • Authors: Jong Wan Ko; Eun Jin Son, Chan Beum Park
      Abstract: Biomineralization is a biogenic process that produces elaborate inorganic and organic hybrid materials in nature. Inspired by the natural process, this study explores novel mineralization approach to create nanostructured CaCO3 films composed of amorphous CaCO3 hemispheres using catechol-rich polydopamine (PDA) as a biomimetic mediator. We successfully transformed thus-synthesized biomimetic CaCO3 to nanostructured films of metal oxide minerals, such as FeOOH, CoCO3, NiCO3, and MnOOH, via a simple procedure. CaCO3-templated metal oxide minerals functioned as an efficient electrocatalyst; CaCO3-templated CoPi (nanoCoPi) film exhibited high stability as a water oxidation electrocatalyst with a current density of 1.5 mA cm-2. The nanostructure of nanoCoPi consisting of individual nanoparticles (~70 nm) and numerous internal pores (BET surface area: 3.17 m2g-1) facilitated an additional charge transfer pathway from the electrode to individual active sites of catalysts. This work demonstrates a plausible strategy for facile and green synthesis of nanostructured electrocatalysts through biomimetic CaCO3 mineralization.
      PubDate: 2017-05-10T23:55:24.544407-05:
      DOI: 10.1002/cssc.201700616
       
  • Highly efficient and uniform 1 cm² perovskite solar cells with an
           electrochemically deposited NiOx hole-extraction layer
    • Authors: Ik Jae Park; Gyeongho Kang, Min Ah Park, Ju Seong Kim, Se Won Seo, Dong Hoe Kim, Kai Zhu, Taiho Park, Jin Young Kim
      Abstract: Given that the highest certified conversion efficiency of the organic-inorganic perovskite solar cell (PSC) is already over 22%, which is even higher than that of the polycrystalline silicon solar cell, the significance of new scalable processes that can be utilized for preparing large-area devices and their commercialization is rapidly increasing. From this perspective, the electrodeposition method is one of the mostly suitable processes for preparing large-area devices, because it is an already commercialized process with proven controllability and scalability. Here, we report highly uniform NiOx layer prepared by the electrochemical deposition process as an efficient hole-extraction layer of a p-i-n type planar PSC with a large active area of> 1 cm². We demonstrate that the increased surface roughness of the NiOx layer, achieved by controlling the deposition current density, facilitates the hole extraction at the interface between perovskite and NiOx, and thus increases the fill factor and the conversion efficiency. The electrochemically deposited NiOx layer also exhibits extremely uniform thickness and morphology, leading to the highly efficient and uniform large-area PSCs. As a result, the p-i-n type planar PSC with an area of 1.084 cm² exhibits a stable conversion efficiency of 17.0% (19.2% for 0.1 cm²) without showing hysteresis effect.
      PubDate: 2017-05-10T09:55:24.382115-05:
      DOI: 10.1002/cssc.201700612
       
  • Comment on “Flexible Asymmetric Supercapacitors Based on Nitrogen-Doped
           Graphene Hydrogels with Embedded Nickel Hydroxide Nanoplates”
    • Authors: Sascha Vongehr
      Abstract: It is argued that the main claims of “Flexible Asymmetric Supercapacitors Based on Nitrogen-Doped Graphene Hydrogels with Embedded Nickel Hydroxide Nanoplates” are strongly exaggerated. By selecting first a subregion (ΔV) of the total voltage drop, the capacitance (CΔV) is inflated by 30 %. Then, by selecting different regions for different properties and using different ΔV values in different terms of a single expression for the energy density (EΔV), the value is doubled. A bending angle of only 45° is instead claimed to be 180°.
      PubDate: 2017-05-10T07:45:37.812628-05:
      DOI: 10.1002/cssc.201700330
       
  • Alcoholysis: A Promising Technology for Conversion of Lignocellulose and
           Platform Chemicals
    • Authors: Shanhui Zhu; Jing Guo, Xun Wang, Jianguo Wang, Weibin Fan
      Abstract: In the catalytic conversion of lignocellulose to valuable products, the first entry point is to break down these biopolymers to sugar units or aromatic monomers, which is conventionally achieved by hydrolysis in water medium. Recent years have seen tremendous progress in alcoholysis process that possesses remarkable advantages such as the avoidance of treating waste water, suppression of humins or chars as well as increase of reaction rate and product yield. Here, the advances have been focused on the alcoholysis of cellulose, hemicellulose and lignin to alkyl glucosides, xylosides and aromatic monomers, respectively. We also summarize the alcoholysis of platform molecule furfuryl alcohol (FAL) to alkyl levulinate (AL) and integrated alcoholysis of cellulose and furfural into AL. This review highlights the comparisons between alcoholysis and hydrolysis, alcoholysis mechanism and future challenges for industrial applications.
      PubDate: 2017-05-09T03:24:13.615442-05:
      DOI: 10.1002/cssc.201700597
       
  • Carbon-Free O2 Cathode with Three-Dimensional Ultralight Nickel Foam
           Supported Ruthenium Electrocatalysts for Li-O2 Batteries
    • Authors: Ziqiang Liu; Ningning Feng, Zihan Shen, Fujun Li, Ping He, Huigang Zhang, Haoshen Zhou
      Abstract: Rechargeable Li-O2 batteries have received substantial attentions because of their high theoretical energy density. However, traditional carbon and binder-containing cathodes suffer from scientific and technical challenges for practical applications, such as high polarization and poor cycle life. We present a carbon and binder-free monolithic O2 cathode with Ru nanoparticle-coated on an ultralight nickel foam. This ultralight and monolithic structure leads to an ~300 times higher capacity than conventional carbon-free metal O2 cathode. The all metal structure enhances the electron transport and suppresses the CO2 evolution, which is the key factor of capacity fade of carbon-based Li-O2 batteries. The ultralight electrode structure has large surface/volume ratio and significantly lowers the mass of inactive components, which is important for a practical application.
      PubDate: 2017-05-08T11:20:26.928671-05:
      DOI: 10.1002/cssc.201700567
       
  • Gliding Arc Plasmatron: providing an alternative method for carbon dioxide
           conversion
    • Authors: Marleen Ramakers; Georgi Trenchev, Stijn Heijkers, Weizong Wang, Annemie Bogaerts
      Abstract: Low temperature plasmas are gaining a lot of interest forenvironmental and energy applications. A large research field in these applications is the conversion of CO2 into chemicals and fuels. Since CO2 is a very stable molecule, a key performance indicator for the research on plasma-based CO2 conversion is the energy efficiency. Until now, the energy efficiency in atmospheric plasma reactors is quite low, and therefore we employ here a novel type ofplasma reactor, the Gliding Arc Plasmatron (GAP). This paper provides a detailed experimental and computational study of the CO2 conversion, as well as the energy cost and efficiency in a GAP. A comparison with thermal conversion, other plasma types and other novel CO2 conversion technologies is made to find out whether thisnovel plasma reactor can provide a significant contribution to the much-needed efficient conversion of CO2. From these comparisons it becomes evident that our results currently obtained are less than a factor two away from being cost competitive and already outperformseveral other novel technologies. Furthermore, we indicate how the performance of the GAP can still be improved by further exploiting its non-equilibrium character. Hence, it is clear that the GAP is very promising for CO2 conversion.
      PubDate: 2017-05-08T06:20:28.411982-05:
      DOI: 10.1002/cssc.201700589
       
  • Non-conjugated polymer as an Efficient Dopant-Free Hole-Transporting
           Material for Perovskite Solar Cells
    • Authors: Yachao Xu; Tongle Bu, Meijin Li, Tianshi Qin, Chengrong Yin, Nana Wang, Renzhi Li, Jie Zhong, Fuzhi Huang, Hai Li, Yong Peng, Jianpu Wang, Linghai Xie, Wei Huang
      Abstract: A novel non-conjugated polymer (PVCz-OMeDAD) with good solution processability was developed to serve as an efficient dopant-free hole transporting material (HTM) for perovskite solar cells (PSCs). PVCz-OMeDAD was simply prepared by the free-radical polymerization of vinyl monomer which was synthesized from low cost raw materials via three high-yield synthesis steps. The combination of flexible non-conjugated polyvinyl main chain and hole-transporting methoxydiphenylamine-substituted carbazole side chain endowed PVCz-OMeDAD with excellent film-forming ability, suitable energy level, high hole mobility and low interfacial charge recombination. As a result, by using a ultra-thin (30 nm) PVCz-OMeDAD film as cost-effective dopant-free polymer HTM, the conventional n-i-p structure PSCs demonstrated a power conversion efficiency (PCE) up to 16.09%, suggesting its great potential for future low-cost large-scale flexible PSCs application
      PubDate: 2017-05-08T05:24:50.006857-05:
      DOI: 10.1002/cssc.201700584
       
  • High Photon-to-Current Conversion in Solar Cells based on Light Absorbing
           Silver-Bismuth-Iodide with Space Group R¯3m Crystal Structure
    • Authors: Huimin Zhu; Mingao Pan, Malin B. Johansson, Erik Johansson
      Abstract: In this report a lead-free silver-bismuth-iodide (AgI:BiI3) with a crystal structure with space group R3m is investigated for use in solar cells. Devices based on the silver-bismuth-iodide deposited from solution on top of TiO2, and the conducting polymer P3HT as a hole transport layer, are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2 %, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45 %. The results are compared to solar cells based on the previously reported material AgBi2I7, and we observe a clearly higher performance for the devices with the new silver-bismuth-iodide composition and different crystal structure. The XRD spectrum of the most efficient silver-bismuth-iodide material shows a hexagonal crystal structure with space group R3m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells.
      PubDate: 2017-05-08T05:24:41.878992-05:
      DOI: 10.1002/cssc.201700634
       
  • Coatable Li4SnS4 solid electrolytes prepared from aqueous solutions for
           all-solid-state lithium-ion batteries
    • Authors: Young Eun Choi; Kern Ho Park, Dong Hyeon Kim, Dae Yang Oh, Hi Ram Kwak, Young-Gi Lee, Yoon Seok Jung
      Abstract: Bulk-type all-solid-state lithium-ion batteries (ASLBs) for large-scale energy storage applications have emerged as a promising alternative to conventional lithium-ion batteries (LIBs) owing to their superior safety. However, the electrochemical performance of bulk-type ASLBs is critically limited by the low ionic conductivity of solid electrolytes (SEs) and poor ionic contact between the active materials and SEs. Herein, we report the highly conductive (0.14 mS cm-1) and dry-air-stable SEs, Li4SnS4, which are prepared using a scalable aqueous-solution process. An active material (LiCoO2) coated by solidified Li4SnS4 from aqueous solutions results in a significant improvement in the electrochemical performance of ASLBs. Side effect by the exposure of LiCoO2 to aqueous solutions is minimized by using predissolved Li4SnS4 solution.
      PubDate: 2017-05-08T03:23:09.496964-05:
      DOI: 10.1002/cssc.201700409
       
  • Enhancing the Acylation Activity of Acetic Acid by Forming an Intermediate
           Aromatic Ester
    • Authors: Nhung Duong; Bin Wang, Tawan Sooknoi, Steven P. Crossley, Daniel E. Resasco
      Abstract: Acylation is an effective C-C bond forming reaction to condense acetic acid and lignin-derived aromatic compounds into acetophenones, valuable precursors to fuels and chemicals. However, acetic acid is intrinsically an ineffective acylating agent. Here, we report that its acylation activity can be greatly enhanced by forming intermediate aromatic esters, directly derived from acetic acid and phenolics. Additionally, the acylation reaction was studied in the liquid phase over acid zeolites and was found to happen in two steps, (1) formation of an acylium ion and (2) C-C bond formation between acylium ion and the aromatic substrate. Each one of these steps can be rate-limiting, depending on the type of acylating agent and aromatic substrate. The O-containing substituents such as -OH and -OCH3 can activate aromatic substrates for step (2), with -OH> -OCH3, while alkyl substituent -R cannot. At the same time, the aromatic esters can rearrange to acetophenones via both an intramolecular pathway and, preferentially, an intermolecular one.
      PubDate: 2017-05-07T21:23:12.827648-05:
      DOI: 10.1002/cssc.201700394
       
  • Freestanding Gold/Graphene-Oxide/MnO2 Microsupercapacitor Displaying High
           Areal Energy Density
    • Authors: ahiud morag; james becker, Raz Jelinek
      Abstract: Microsupercapacitors are touted as one of the promising "next frontiers" in energy storage research and applications. Despite their potential, significant challenges still exist in term of physical properties and electrochemical performance, particularly attaining high energy density, stability, ease of synthesis, and feasibility of large-scale production. We present new freestanding microporous electrodes comprising self-assembled scaffold of gold and reduced graphene oxide (rGO) nanowires coated with MnO2. The electrodes exhibited excellent electrochemical characteristics, particularly superior high areal capacitance. Importantly, the freestanding Au/rGO scaffold also served as the current collector, obviating the need for an additional electrode support required in most reported supercapacitors, thus enabling low volume and weight devices with a high overall device specific energy. Stacked symmetrical solid-state supercapacitors were fabricated using the Au/rGO/MnO2 electrodes in parallel configurations showing the advantage of using freestanding electrodes in the fabrication of low volume devices.
      PubDate: 2017-05-05T05:23:37.694183-05:
      DOI: 10.1002/cssc.201700500
       
  • Sustainable gel electrolyte containing pyrazole as corrosion inhibitor and
           dendrite suppressor for aqueous Zn/LiMn2O4 battery
    • Authors: Tuan Hoang; The Nam Long Doan, Julie Hyeonjoo Cho, Jane Ying Jun Su, Christine Lee, Changyu Lu, Pu Chen
      Abstract: The Zn anode in secondary aqueous batteries suffers from dendrite formation and corrosion. In this work, the dendrite is suppressed by using a simple but novel gel electrolyte containing fumed silica and an additive. The dendrite suppression is evidenced by chronoamprometry and ex-situ scanning electron microscopy examinations. Pyrazole as the additive in the electrolyte has been implemented. It is found that the presence of 0.2 wt% of pyrazole in the electrolyte helps minimize both corrosion and dendrite formation. The Zn/LiMn2O4 battery using pyrazole containing gel electrolytes exhibits high cyclability, up to 85% capacity retention after 500 charge-discharge cycles at 4C. This is 8% higher than the performance of the reference battery (using aqueous electrolyte containing 2M Li2SO4 and 1M ZnSO4). Furthermore, self-discharge of the battery with the pyrazole-containing gel electrolyte is suppressed, evidenced by open-circuit voltage loss of 20% smaller, compared to the performance of the reference battery, after 24-hour monitoring. Float charge current density under constant voltage 2.1V also significantly decreases, from about 8.0 µA to 3-6 µA.
      PubDate: 2017-05-04T13:20:42.643281-05:
      DOI: 10.1002/cssc.201700441
       
  • Polycyclization Enabled by Relay Catalysis: One-Pot Manganese-Catalyzed
           C-H Allylation and Silver-Catalyzed Povarov Reaction
    • Authors: Shi-Yong Chen; Qingjiang Li, Xu-Ge Liu, Jia-Qiang Wu, Shang-Shi Zhang, Honggen Wang
      Abstract: Described herein is a Mn(I)/Ag(I) based relay catalysis for the one-pot synthesis of polycyclics via a formal [3+2] and [4+2] cyclization reaction. The manganese catalyzed the first example of directed C-H allylation with allenes, setting the stage for an in-situ Povarov cyclization catalyzed by Ag(I). High bond-forming efficiency (3 x C-C bonds), broad substrate scope, high regio- and stereoselectivity and 100% atom-economy were observed.
      PubDate: 2017-05-04T10:15:56.11865-05:0
      DOI: 10.1002/cssc.201700452
       
  • Electrochemically-driven fermentation of organic substrates with undefined
           mixed microbial cultures
    • Authors: Marianna Villano; Paola Paiano, Enza Palma, Alfredo Miccheli, Mauro Majone
      Abstract: Growing scientific interest in mixed microbial culture-based anaerobic biotechnologies for the production of value-added chemicals and fuels from waste organic residues requires a parallel focus on the development and implementation of strategies to control products distribution. This study examined the feasibility of an electro-fermentation approach, based on the introduction of a polarized (-700 mV vs. the standard hydrogen electrode) graphite electrode in the fermentation medium, to steer products distribution during the conversion of organic substrates (glucose, ethanol, and acetate supplied as single compounds or in mixtures) by undefined mixed microbial cultures. As a main result, in batch experiments the polarized electrode triggered a nearly 20-fold increase (relative to open circuit controls) in the yield of i-butyrate production (0.43±0.01 vs. 0.02±0.02 mol/ mol glucose) during the anaerobic fermentation of the ternary mixture of substrates, without adversely affecting the rate of substrate bioconversion. The observed change in the fermentative metabolism was most likely triggered by the (potentiostatic) regulation of the oxidation-reduction potential of the reaction medium rather than by the electrode serving as an electron donor.
      PubDate: 2017-05-04T07:15:37.59715-05:0
      DOI: 10.1002/cssc.201700360
       
  • Serrated Au/Pd core/shell nanowires with jagged edges for boosting liquid
           fuel electrooxidation
    • Authors: Yu-Ling Zhang; Wen-Jin Shen, Wen-Tao Kuang, Shaojun Guo, Yong-Jun Li, Wang Ze-Hong
      Abstract: Integration of one-dimensional (1D), core/shell and jagged features into one entity may provide a promising avenue for further enhancing catalyst's performance. However, designing such unique nanostructures is extremely challenging. Herein, 1D serrated Au/Pd core/shell nanowires (CSNWs) with jagged edges were produced simply by one-pot, dual capping agent-assisted method, involving co-reduction, galvanic replacement, directional coalescence of preformed nanoparticles and site-selective epitaxial growth of Pd. As-prepared Au/PdCSNWs, compared with the commercial Pd/C, exhibited enhanced electrocatalytic performance towards liquid fuel oxidation because of the synergistic effect of the electronic structure and low-coordinated jagged edges.
      PubDate: 2017-05-02T21:20:33.327907-05:
      DOI: 10.1002/cssc.201700602
       
  • Polybenzoxazine-derived Nitrogen-Doped Carbon as Matrix for Powder-based
           Electrocatalysts
    • Authors: Stefan Barwe; Corina Andronescu, Justus Masa, Edgar Ventosa, Stefan Klink, Aziz Genç, Jordi Arbiol, Wolfgang Schuhmann
      Abstract: Besides catalytic activity, intrinsic stability, tight immobili¬sation on a suitable electrode surface and sufficient electronic con¬ductivity are fundamental prerequisites for the long-term operation of particle and especially powder-based electrocatalysts. We present a novel approach to concurrently address these challenges by using the unique properties of polxbenzoxazine (pBO) polymers, namely near-zero shrinkage and high residual char yield even after pyrolysis at high temperatures. Pyrolysis of a nanocubic Prussian blue analogue KmMnx[Co(CN)6]y x nH2O precursor embedded in a bisphenol A and aniline based pBO led to the formation of a N-doped carbon matrix modified with MnxCoyOz nanocubes. The obtained electrocatalyst exhibits high efficiency towards the oxygen evolution reaction (OER) and more importantly a stable performance for at least 65 h.
      PubDate: 2017-05-02T21:20:27.640715-05:
      DOI: 10.1002/cssc.201700593
       
  • New insights into the reactivity of biomass with butenes for the synthesis
           of butyl levulinates
    • Authors: Alexandre Démolis; Marion Eternot, Nadine Essayem, Franck Rataboul
      Abstract: This article reports a detailed study on the reactivity of levulinic acid and cellulose with 1-butene and iso-butene for the catalytic formation of sec- and tert-butyl levulinates. The influence of catalyst type and various solvent conditions has been particularly investigated to assess the potential of sustainable transformation. For instance we found a very simple and efficient procedure using reusable Amberlyst-15 in the absence of solvent to form, from levulinic acid and iso-butene, tert-butyl levulinate (70% yield) a compound very difficult to prepare by other means. sec-Butyl levulinate (66% yield) was obtained using Amberlyst-15 in gamma-butyrolactone as biosourced solvent. We also notably extended the original procedure using directly cellulose as reactant. In the presence of a catalytic amount of sulfuric acid, it was possible to form sec-butyl levulinate (19% yield) from 1-butene in a more efficient way than using the alcohol as esterifying agent.
      PubDate: 2017-05-02T11:02:45.931078-05:
      DOI: 10.1002/cssc.201700416
       
  • Polyimidazolium Salts: Robust Catalysts for the Cycloaddition of Carbon
           Dioxide into Carbonates that Operate at Atmospheric Pres-sure Under
           Solvent-Free Conditions
    • Authors: Felix Daniel Bobbink; Wei Zhong, Zhaofu Fei, Paul J. Dyson
      Abstract: There is growing interest in sustainable heterogeneous catalysts based on organic polymers. Here, we describe a series of polyimidazolium salt catalysts, prepared from the direct reaction of arene-bridged bis- and tris-alkyl halides with trimethylsilylimidazole. The polyimidazolium salts were characterized by spectroscopic and analytical techniques and it was found that their morphology and porosity could be controlled by adjusting the steric parameters of the spacer in the alkyl-halide starting materials. Moreover, the polymers are excellent heterogeneous organocatalysts for the cycloaddition of CO2 to epoxides to afford cyclic carbonates at atmospheric pressure under solvent-free conditions. The polymer catalysts exhibit long-term stability and may be recycled and reused at least 10 times.
      PubDate: 2017-05-02T10:49:00.452948-05:
      DOI: 10.1002/cssc.201700570
       
  • Ultra-Thin Alginate Coatings as Selective Layers for Nanofiltration
           Membranes with High Performance
    • Authors: Yong Du; Chao Zhang, Qi-Zhi Zhong, Xi Yang, Jian Wu, Zhi-Kang Xu
      Abstract: It is highly desirable to develop environmental friendly processes for fabricating thin film composite (TFC) nanofiltration membranes (NFMs) from natural materials. However, nanofiltration performance of such TFC NFMs is not satisfactory for practical applications due to the lack of efficient methods for constructing those ultra-thin, uniform and stable coatings as the selective layers. Here we demonstrate a contra-diffusion strategy for fabricating TFC NFMs with ultra-thin crosslinked alginate coatings as the selective layers without any organic solvent involved. The as-prepared NFMs show nearly one order of magnitude higher water permeation flux than other alginate-based TFC NFMs with similar salt rejection, representing the best performance among all TFC NFMs from natural materials. These NFMs also possess excellent mono-/divalent ion selectivity, along with good long-term operation stability and antifouling property. Furthermore, our strategy has the maximized reactant usage rate and the minimized waste discharge, which provides new insight into the environmental friendly fabrication of TFC NFMs.
      PubDate: 2017-05-02T09:54:51.324744-05:
      DOI: 10.1002/cssc.201700519
       
  • Fluoropolymer Stabilized Chromophore-Catalyst Assemblies in Aqueous Buffer
           Solutions for Water Oxidation Catalysis
    • Authors: Michael S. Eberhart; Kyung-Ryang Wee, Degao Wang, Seth Marquard, Kasey Skinner, Animesh Nayak, Thomas J Meyer
      Abstract: We describe here application of the fluorinated polymer (Dupont AF, a copolymer of 4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole and tetrafluoroethylene) in stabilizing phosphonate-derivatized molecular assemblies on oxide electrodes. In the procedure, the polymer is dip coated onto the surfaces of oxide electrodes with pre-bound, phosphonate-derivatized chromophores and assemblies including assemblies for water oxidation. The results of our experiments demonstrate a high degree of stabilization by the added polymer and a demonstration of its use in stabilizing surface-bound assemblies for water oxidation catalysis.
      PubDate: 2017-04-28T12:00:19.682151-05:
      DOI: 10.1002/cssc.201700630
       
  • Engineering Pores of Biomass-Derived Carbon: Insights for Achieving
           Ultra-high Stability at High Power in High-Energy Supercapacitors
    • Authors: Yun-Sung Lee; Ranjith Thangavel, Karthikeyan Kaliyappan, Hari Vignesh Ramasamy, Xueliang Sun
      Abstract: Electrochemical supercapacitors possessing a high energy density are promising devices due to their simple construction and long-term cycling performance. Developing a supercapacitor based on electrical double layer charge storage with high energy density while preserving its cyclability at higher power presents an ongoing challenge. We hereby provide the insights for achieving a high energy density at high power with an ultra-high stability in Electrical Double Layer Capacitor (EDLC) system utilizing carbon from a biomass—cinnamon sticks in a sodium ion organic electrolyte. We have deeply investigated the dependence of EDLC performance on structural, textural, & functional properties of porous carbon engineered by various activation agents. The results demonstrate that the performance of EDLCs not dependent on their textural properties, but on their structural features & surface functionalities, which is evident from electrochemical studies. The results are highly promising, that porous carbon with poor textural properties has great potential to deliver high capacitance & outstanding stability of 300,000 cycles, than the carbon with good textural properties. An ultra-low capacitance degradation of ~0.066% per 1000 cycles along with high energy (~70 Wh kg-1) and high power have been achieved, emerging as a high energy supercapacitor. The results open a new platform for application of low-surface area biomass carbons in establishing highly stable high-energy supercapacitors.
      PubDate: 2017-04-28T09:29:43.320755-05:
      DOI: 10.1002/cssc.201700492
       
  • Effect of Donor Strength and Bulk on Thieno[3,4 b]pyrazine based
           Panchromatic Dyes in DSCs
    • Authors: Nalaka P. Liyanage; Hammad Cheema, Alexandra R. Baumann, Alexa R. Zylstra, Jared Heath Delcamp
      Abstract: NIR absorbing organic dyes are critically needed in dye-sensitized solar cells (DSCs). Thieno[3,4-b]pyrazine (TPz) based dyes can access the near-infrared (NIR) spectral region and show power conversion efficiencies (PCEs) of up to 8.1% with sunlight being converted at wavelengths up to 800 nm for 17.6 mA/cm2 of photocurrent in a co-sensitized DSC device. Precisely controlling dye excited-state energies is critical for good performances in NIR DSCs. Strategies to control TPz dye energetics with stronger donor groups and TPz substituent choice are evaluated in this manuscript. Additionally, donor size influence versus dye loading on TPz dyes is analysed with respect to TiO2 surface protection designed to prevent recombination of electrons in TiO2 with the redox shuttle. Importantly, the dyes evaluated were demonstrated to work well with low Li+ concentration electrolytes, with iodine and cobalt redox shuttle systems, and efficiently as part of co-sensitized devices.
      PubDate: 2017-04-25T13:20:30.050329-05:
      DOI: 10.1002/cssc.201700546
       
  • Interconnected 3D Network of Carbon Dots decorated Reduced Graphene Oxide
           Nanosheets for High-Performance Supercapacitors
    • Authors: Mingtao Zheng; Xiao Zhao, Ming Li, Hanwu Dong, Yingliang Liu, Hang Hu, Yijin Cai, Yeru Liang, Yong Xiao
      Abstract: Interconnected 3D network of reduced graphene oxide decorated with carbon dots (rGO/CDs) nanosheets are successfully fabricated via a simple one-pot hydrothermal process. The as-prepared rGO/CDs present appropriate 3D interconnected structure and abundant oxygen-containing functional groups, which attribute to excellent electrochemical performance such as high specific capacitance, good rate capability, and great cycling stability. Employed as binder-free electrodes for supercapacitor, the as-resulted rGO/CDs exhibit excellent long-term cycling stability (ca. 92% capacitance retention after 20,000 charge/discharge cycles at current density of 10 A g-1) as well as a maximum specific capacitance of ca. 308 F g-1 at current density of 0.5 A g-1, which is much higher than that of rGO (200 F g-1) and individual CDs (2.2 F g-1). This work provides a promising strategy to fabricate graphene-based nanomaterials with greatly boosted electrochemical performances by decoration of rGO with CDs.
      PubDate: 2017-04-24T22:20:32.978364-05:
      DOI: 10.1002/cssc.201700474
       
  • Ehanced Solar Water Splitting by Swift Charge Separation in Au/FeOOH
           Sandwiched Single Crystalline Fe2O3 Nanoflake Photoelectrodes
    • Authors: Lei Wang; Nhat Truong Nguyen, Yajun Zhang, Yingpu Bi, Patrik Schmuki
      Abstract: In this work, single crystalline α-Fe2O3 nanoflakes (NFs) are formed in a highly dense array by Au seeding of a Fe substrate by a thermal oxidation technique. The NFs are conformally decorated with a thin FeOOH cocatalyst layer. Photoelectrochemical (PEC) measurements show that this photoanode with the α-Fe2O3/FeOOH NFs rooted on the Au/Fe structure exhibits a significantly enhanced PEC water oxidation performance compared to the plain α-Fe2O3 nanostructure on the Fe substrate. The α-Fe2O3/FeOOH NFs on Au/Fe photoanode yields a photocurrent density of 3.1 mA cm-2 at 1.5 VRHE, and a remarkably low onset potential of 0.5-0.6 VRHE in 1 M KOH under AM 1.5G (100 mW cm-2) simulated sunlight illumination. The enhancement in PEC performance can be attributed to a synergistic effect of the FeOOH top decoration and Au under-layer. While FeOOH facilitates hole transfer at the interface of electrode/electrolyte, the Au layer provides a sink for the electron transport to the back contact: this leads overall to a drastically improved charge-separation efficiency in the single crystalline α-Fe2O3 NF photoanode.
      PubDate: 2017-04-24T11:20:50.124317-05:
      DOI: 10.1002/cssc.201700522
       
  • Solvent-free mechanochemical synthesis of nitrogen-doped nanoporous carbon
           for electrochemical energy storage
    • Authors: Christina Schneidermann; Nicolas Jaeckel, Steffen Oswald, Lars Giebeler, Volker Presser, Lars Borchardt
      Abstract: Nitrogen-doped nanoporous carbons have been synthesized by a solvent-free mechanochemically-induced one-pot synthesis. This facile approach involves the mechanochemical treatment and carbonization of three solid materials: potassium carbonate, urea, and lignin, which is a waste product from pulp industry. The resulting nitrogen-doped porous carbons offer a very high specific surface area up to 3000 m2 g-1 and large pore volume up to 2 cm3 g-1. The mechanochemical reaction and the impact of activation and functionalization are investigated by nitrogen- and water physisorption and high-resolution X-ray photoelectron spectroscopy (XPS). Our N-doped carbons are highly suitable for electrochemical energy storage as supercapacitor electrodes, showing high specific capacitances in aqueous 1 M Li2SO4 electrolyte (177 F g−1), organic 1 M tetraethylammonium tetrafluoroborate in acetonitrile (147 F g−1), and an ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate; 192 F g-1. This new mechanochemical pathway synergistically combines attractive energy storage ratings with a scalable, time-efficient, cost-effective, and environmentally favorable synthesis.
      PubDate: 2017-04-24T04:21:13.881115-05:
      DOI: 10.1002/cssc.201700459
       
  • Potassium-promoted molybdenum carbide as a highly active and selective
           catalyst for CO2 conversion to CO
    • Authors: Marc D Porosoff; Jeffrey W Baldwin, Xi Peng, Giannis Mpourmpakis, Heather D Willauer
      Abstract: The high concentration of CO2 bound in seawater represents a significant opportunity to extract and use this CO2 as a C1 feedstock for synthetic fuels. Through an existing process patented by the U.S. Navy, CO2 and H2 can be concurrently extracted from seawater, then catalytically reacted to produce synthetic fuel. Hydrogenating CO2 directly into liquid hydrocarbons is exceptionally difficult, but by first identifying a catalyst for selective CO production via reverse water-gas shift (RWGS), CO can then be hydrogenated to fuel through Fischer-Tropsch (FT) synthesis. Results of this study demonstrate that potassium-promoted molybdenum carbide supported on γ-Al2O3 (K-Mo2C/γ-Al2O3) is a low-cost, stable and highly selective catalyst for RWGS over a wide range of conversion. These findings are supported by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations
      PubDate: 2017-04-20T14:37:47.526122-05:
      DOI: 10.1002/cssc.201700412
       
  • Dissolving Lignin in Water through Enzymatic Sulfation with Aryl
           Sulfotransferase
    • Authors: Pepijn Prinsen; Anand Narani, Aloysius F. Hartog, Ron Wever, Gadi Rothenberg
      Abstract: We introduce the concept of using site-specific sulfation of various lignins for increasing their aqueous solubility and thereby their processability. Using p-nitrophenylsulfate as a sulfate source and an aryl sulfotransferase enzyme as catalyst, lignins are easily sulfated at ambient conditions. We demonstrate the specific sulfation of phenolic hydroxyl groups on five different lignins: Indulin AT (Kraft softwood), Protobind 1000 (mixed wheat straw/Sarkanda grass soda) and three organosolv lignins. The reaction proceeds smoothly and the increase in solubility is visible to the naked eye. We then examine the reaction kinetics, and show that these are easily monitored qualitatively and quantitatively using UV/Vis spectroscopy. The UV/Vis results are validated with 31P NMR spectroscopy of the lignin phenol groups after derivatization with phosphorylation reagent II. In general, the results are more significant with organosolv lignins, as Kraft and soda lignins are produced from aqueous lignocellulose extraction processes.S is for solubility: Site-specific sulfation is introduced and used to increase the aqueous solubility of various lignins, improving then their processability. This concept is demonstrated on five lignins using p-nitrophenylsulfate as a sulfate source and an aryl sulfotransferase enzyme as catalyst.
      PubDate: 2017-04-20T06:42:13.466277-05:
      DOI: 10.1002/cssc.201700376
       
  • Pectin, Hemicellulose or Lignin? Impact of the Biowaste Source on the
           Performance of Hard Carbons for Sodium ion Batteries
    • Authors: xinwei Dou; Ivana Hasa, Maral Hekmatfar, Thomas Diemant, R. Juergen Behm, Daniel Buchholz, Stefano Passerini
      Abstract: Hard carbons are currently the most widely used negative electrode materials in Na-ion batteries. This is due to their promising electrochemical performance with capacities of 200-300 mAh g-1 and stable long-term cycling. However, an abundant and cheap carbon source is necessary in order to comply with the low-cost philosophy of the Na-ion technology. As a matter of fact, many biologic or waste materials have been used to synthesize hard carbons but the impact of the precursors on the final properties of the anode material is not fully understood. In this study we unravel the impact of the biomass source on the structural and electrochemical properties of hard carbons, using different, representative types of biomass as examples. The systematic structural and electrochemical investigation of hard carbons derived from different sources, namely corncobs, peanut shells and waste apples, representatives of hemicellulose-, lignin- and pectin- rich biomass, respectively, enables to understand and interlink the structural and electrochemical properties.
      PubDate: 2017-04-20T04:32:29.795101-05:
      DOI: 10.1002/cssc.201700628
       
  • Green processing of lignocellulosic biomass and its derivatives in deep
           eutectic solvents
    • Authors: Xing Tang; Miao Zuo, Zheng Li, Huai Liu, Caixia Xiong, Xianhai Zeng, Yong Sun, Lei Hu, Tingzhou Lei, Shijie Liu, Lu Lin
      Abstract: The scientific community has been seeking cost-competitive and green solvents with good dissolving capacity for the valorization of lignocellulosic biomass. At this point, deep eutectic solvents (DESs) are currently emerging as a new class of promising solvents, which are generally liquid eutectic mixtures formed by self-association (or hydrogen-bonding interaction) of two or three components. DESs are attractive solvents for the fractionation (or pretreatment) of lignocellulose and the valorization of lignin, owing to the high solubility of lignin in DESs. DESs are also employed as effective media for the modification of cellulose to afford functionalized cellulosic materials like cellulose nanocrystals (CNCs). More interestingly, biomass-derived carbohydrates such as fructose can be used as one of the constituents of DESs and then dehydrated to 5-hydroxymethylfurfural (HMF) with high yields. In this review, we comprehensively summarize the recent contribution of DESs to the processing of lignocellulosic biomass and its derivatives. Moreover, further discussion about the challenges of the application of DESs in biomass processing is represented.
      PubDate: 2017-04-20T00:30:54.694841-05:
      DOI: 10.1002/cssc.201700457
       
  • Tandem Transformation of Nitro Compounds to N-methylated Amines: Greener
           Strategy for the Utilization of Methanol as a Methylating Agent
    • Authors: Bhaskar Paul; Sujan Shee, Kaushik Chakrabarti, Sabuj Kundu
      Abstract: A simple air and moisture stable, highly efficient NNN ruthenium catalyst is reported for the first time to catalyse the tandem transformation of various aromatic and aliphatic nitro compounds to the corresponding N-methylated amines up to 98% yields using methanol as a green and sustainable methylating agent. Gram scale reactions using challenging nitro substrates demonstrated the practical application aspects of this catalytic system. Importantly, N-methylamine group was smoothly introduced to various complex molecular setting without using any expensive Pd/phosphine/amine based cross coupling reaction.
      PubDate: 2017-04-19T08:23:21.061402-05:
      DOI: 10.1002/cssc.201700503
       
  • Synergetic Effect of Chloride Doping and CH3NH3PbCl3 on CH3NH3PbI3-xClx
           Perovskite Based Solar Cells
    • Authors: Feng Xu; Taiyang Zhang, Ge Li, Yixin Zhao
      Abstract: The chloride doped CH3NH3PbI3-xClx perovskite had attracted great attention due to obvious performance enhancement with using of Cl additive and the controversial arguments on Cl function and mechanism behind it. Herein, we fabricated a series of CH3NH3PbI3-xClx perovskites with various Cl content via a gas/solid reaction between CH3NH2 gas with HPbI3-xClx (x=0-1). It is found that once the Cl content x>0.1, there is CH3NH3PbCl3 formed coexisted with CH3NH3PbI3-xClx(x=0.05-01). The small amount of Cl doping in CH3NH3PbI3-xClx(x=0.05) could significantly increase the perovskite's grain size and the phase pure CH3NH3PbI2.95Cl0.05 perovskites exhibited up to 17.44% efficiency. In contrast, the co-existed wide band gap CH3NH3PbCl3 perovskites inhibit the electron transfer when there is large amount of Cl in CH3NH3PbI3-xClx.
      PubDate: 2017-04-19T00:22:27.26164-05:0
      DOI: 10.1002/cssc.201700487
       
  • Controlled Growth of CH3NH3PbI3 using a Dynamically Dispensed Spin-Coating
           Method: Improving Efficiency with a Reproducible PbI2 Blocking Layer
    • Authors: Yingzhuang Ma; Parth Vashishtha, Kai Chen, Elijah Peach, David Ohayon, Justin Hodgkiss, Jonathan Halpert
      Abstract: It is commonly believed that excess PbI2 has beneficial effects for perovskite solar cells due to the modification of charge transport behavior at interfaces, by surface passivation and by blocking electron-hole recombination. Here, we introduce a dynamically dispensed spin coating technique in a two-step deposition to form a perovskite layer with controllable quantities of crystalline PbI2. Using this technique, the concentration of CH3NH3I solution is kept constant at the reaction interface, ensuring smooth growth of films. By changing the spinning rate during the reaction, the PbI2 conversion ratio and perovskite cuboid size can be optimized, resulting in a power conversion efficiency improvement over control devices. This dynamically dispensed technique represents a repeatable method for compositional control in perovskite solar cells and improves our understanding of how a PbI2 blocking layer improves the performance of perovskite solar cells.
      PubDate: 2017-04-19T00:22:14.172644-05:
      DOI: 10.1002/cssc.201700449
       
  • Low Temperature Modification of ZnO Nanoparticle Film for an Electron
           Transport Layer of Planar Perovskite Solar Cells
    • Authors: Gill Sang Han; Hyun Woo Shim, Seongha Lee, Matthew Duff, Jung-Kun Lee
      Abstract: An electron transport layer (ETL) which selectively collects photogenerated electrons is an important constituent of halide perovskite (PSCs). While TiO2 film is widely used as an ETL of PSCs, the processing of TiO2 film with high electron mobility requires high temperature annealing and TiO2 dissociates the perovskite layer through a photocatalytic reaction. In the present study, we report an effective surface modification method of a room-temperature processed ZnO nanoparticle (NPs) layer as an alternative to TiO2 ETL. A combination of simple UV exposure and nitric acid treatment effectively removes the hydroxyl group and passivate surface defects in ZnO NPs. The surface modification of ZnO NPs increases PCE of PSCs increases to 14% and decreases the aging of PSCs under light soaking. These results suggest that the surface modified ZnO film can be a good ETL of PSCs and provide a path toward low temperature processing of efficient and stable PSCs that are compatible with flexible electronics.
      PubDate: 2017-04-17T11:20:32.116545-05:
      DOI: 10.1002/cssc.201700029
       
  • A reversed photosynthesis-like process for light-triggered CO2 capture,
           release and conversion
    • Authors: Yapei Wang; Dingguan Wang, Shenglong Liao, Shiming Zhang
      Abstract: Materials for CO2 capture have been extensively exploited for climate governance and gaseous separation. However, their regeneration is facing the problems of high energy cost and secondary CO2 contamination. Herein, a reversed photosynthesis-like process is proposed, which absorbs CO2 in darkness while releases CO2 under light illumination. The process is likely supplementary to natural photosynthesis of plants which on the contrary release CO2 in nights. Remarkably, the material used in this work is able to capture 9.6 wt.% CO2 according to its active component. Recyclable CO2 capture at room temperature and release under light irradiation ensure its convenient and cost-effective regeneration. Furthermore, CO2 released from the system is successfully converted into stable compound in tandem with specific catalysts.
      PubDate: 2017-04-16T23:15:27.806084-05:
      DOI: 10.1002/cssc.201700365
       
  • A blue diketopyrrolopyrrole sensitizer with high efficiency in NiO based
           dye-sensitized solar cells
    • Authors: Fabrice Odobel; Yoann Farre, Mahfoudh Raissi, Arnaud Fihey, Yann Pellegrin, Errol Blart, Denis Jacquemin
      Abstract: We have prepared a series of four new diketopyrrolopyrroles (DPPs) based sensitizers that exhibit high molar extinction coefficients, extended absorption into the long wavelengths and well suited photoredox properties to act as sensitizers in p-DSSCs. These new DPP dyes, composed of a thienyl DPP core, are substituted on one end either by a thiophene carboxylic (Th) or a 4,4'-((phenyl)aza)dibenzoic acid as anchoring group and, on the other extremity, either by a proton or a naphthalene diimide (NDI) moiety. These new dyes were completely characterized by absorption and emission spectroscopy along with electrochemistry and they were modeled by TD-DFT quantum chemical calculations. The photovoltaic study in p-DSSC with iodine based electrolyte reveals that the dye Th-DPP-NDI is particularly efficient (Jsc = 7.38 mA/cm2; Voc = 147 mV; ff = 0.32;  = 0.35%) and quite active in the low energy part of the solar spectrum (above 700 nm), where few NiO dyes are effective. To illustrate the potential of DPP dyes in photocathode, we have designed a highly efficient tandem DSSC composed of a TiO2 photoanode sensitized by the dye D35 and a NiO photocathode sensitized by Th-DPP-NDI. This tandem DSSC gives the highest performances ever reported (Jsc = 6.73 mA/cm2; Voc = 910 mV;  = 4.1%) and importantly the tandem cell outcompetes with each of the subs-cells.
      PubDate: 2017-04-14T05:25:21.308573-05:
      DOI: 10.1002/cssc.201700468
       
  • Boosting the lifetime and enhancing the efficiency of organic solar cell
           by applying an in situ synthesized low-crystalline (amorphous) ZnO layer
           as a high potential buffer layer
    • Authors: Farzaneh Arabpour Roghabadi; Vahid Ahmadi, bahram abdollahi Nejand, Karim Oniy Aghmiuni
      Abstract: By introducing an in situ-synthesized low-crystalline ZnO (LC-ZnO) (amorphous) layer between the cathode and the active layer of PCPDTBT: CdSe solar cell, the device keeps more than 80% and 40% of its initial lifetime after 180 days and 360 days without any encapsulation, respectively. In this regard, 180 days is the highest lifetime achieved for polymer-based solar cells with direct configuration. In addition, the power conversion efficiency (PCE) is improved up to 70% in the presence of the LC-ZnO interfacial layer. The LC-ZnO layer is synthesized during polymer annealing after solution-deposition of the precursor at a low temperature (140℃) and a short time. Highly crystalline ZnO (HC-ZnO) nanoparticles are also synthesized and applied as an interfacial layer. The results show that LC-ZnO is superior to that of HC-ZnO in acting as cathode interfacial layer and moisture scavenger because of the high coverage and surface area provided by in situ synthesis method.
      PubDate: 2017-04-14T03:10:42.348476-05:
      DOI: 10.1002/cssc.201700259
       
  • Macroporous Silica with Thick Framework for Steam-Stable and
           High-Performance Poly(ethyleneimine)/Silica CO2 Adsorbent
    • Authors: Kyungmin Min; Woosung Choi, Minkee Choi
      Abstract: Poly(ethyleneimine) (PEI)/silica has been widely studied as a solid adsorbent for post-combustion CO2 capture. In this work, a highly macroporous silica (MacS) synthesized by secondary sintering of fumed silica is compared with various mesoporous silicas having different pore structures as a support for PEI. Silicas with large pore diameter and volume enabled high CO2 adsorption kinetics and capacity because pore occlusion by the supported PEI was minimized. The steam stability of the silica structures increased with the silica framework thickness owing to suppressed framework ripening. Silicas with low steam stability showed rapid leaching of PEI, indicating that PEI squeezed out of the collapsed silica pores can be more readily leached. Consequently, the MacS, which simultaneously possessed an extra-large pore volume (1.80 cm3 g−1), pore diameter (56.0 nm) and a thick framework (>10 nm), showed the most promising CO2 adsorption kinetics, capacity, and steam stability.
      PubDate: 2017-04-13T23:20:34.590779-05:
      DOI: 10.1002/cssc.201700398
       
  • Swelling Porous Organic Polymers Bearing Ionic Liquids and
           Metalloporphyrins: Cooperative Synthesis of Cyclic Carbonates from
           Epoxides and CO2 under Ambient Conditions
    • Authors: Yaju Chen; Rongchang Luo, Qihang Xu, Jun Jiang, Xiantai Zhou, Hongbing Ji
      Abstract: A facile and one-pot synthesis of metalloporphyrin-based ionic porous organic polymers (M-iPOPs) was presented through the typical Yamamoto-Ullmann couplings reaction for the first time. Various characterization techniques demonstrated these strong polar aluminum-based materials (Al-iPOP) possessed relatively uniform microporosity, good swellable feature and improved CO2 capture capacity. Considering the special physicochemical properties, heterogeneous Al-iPOP bearing both metal active center and halogen anion acted as a bifunctional catalyst for the solvent- and additive-free synthesis of cyclic carbonates from various epoxides and CO2 with excellent activity and good recyclability under mild conditions. More interestingly, these CO2-philic materials could smoothly catalyze the cycloaddition reaction by using simulated flue gas (15 % CO2 in N2, v/v) as a raw material, indicating a local stable microenvironment and polymer swellability might promote the transformation. Thus, introducing polar ionic liquid units into metalloporphyrin-based porous materials was regarded as a promising new strategy for the chemical conversion of CO2.
      PubDate: 2017-04-13T22:20:31.931637-05:
      DOI: 10.1002/cssc.201700536
       
  • New morpholinium- and piperidinium-based ionic liquids, functionalized
           with ethoxyethyl-side chains, as electrolyte components in lithium and
           lithium-ion batteries
    • Authors: Maria Assunta Navarra; Kanae Fujimura, Mirko Sgambetterra, Akiko Tsurumaki, Stefania Panero, Nobufumi Nakamura, Hiroyuki Ohno, Bruno Scrosati
      Abstract: In the present work, two ionic liquids, N-ethoxyethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide (M1,2O2TFSI) and N-ethoxyethyl-N-methylpiperidinium bis(trifluoromethane-sulfonyl)imide (P1,2O2TFSI) have been synthesized and compared. Fundamental relevant properties, such as thermal and electrochemical stability, density and ionic conductivity were analyzed to evaluate the effects caused by the presence of the ether bond in the side chain and/or in the organic cation ring. Upon lithium salt addition, two electrolytes suitable for lithium batteries applications were found. Higher conducting properties of the piperidinium-based electrolyte resulted in enhanced cycling performances when tested with LiFePO4 (LFP) cathode in lithium cells. When mixing the P1,2O2TFSI / LiTFSI electrolyte with a tailored alkyl carbonate mixture, the cycling performance of both Li and Li-ion cells greatly improved, with prolonged cyclations delivering very stable capacity values, as high as the theoretical one in the case of Li / LFP cell configurations.
      PubDate: 2017-04-13T11:37:02.862743-05:
      DOI: 10.1002/cssc.201700346
       
  • Process Intensification for Cellulosic Biorefineries
    • Authors: Sunitha Sadula; Abhay Athaley, Weiqing Zheng, Marianthi Ierapetritou, Basudeb Saha
      Abstract: Utilization of renewable carbon source, especially non-food biomass is critical to address the climate change and future energy challenge. Current chemical and enzymatic processes for producing cellulosic sugars are multistep, and energy- and water-intensive. Techno-economic analysis (TEA) suggests that upstream lignocellulose processing is a major hurdle to the economic viability of the cellulosic biorefineries. Process intensification, which integrates processes and uses less water and energy, has the potential to overcome the aforementioned challenges. Here, we demonstrate a one-pot depolymerization and saccharification process of woody biomass, energy crops, and agricultural residues to produce soluble sugars with high yields. Lignin is separated as a solid for selective upgrading. Further integration of our upstream process with a reactive extraction step makes energy-efficient separation of sugars in the form of furans. TEA reveals that the process efficiency and integration enable, for the first time, economic production of feed streams that could profoundly improve process economics for downstream cellulosic bioproducts.Sugar, furan, how you get so cheap? Process intensification is an improved strategy for sugars and furans production with high yields and selectivity from multiple non-food biomass with lower consumption of water and energy. Techno-economic analysis shows that the process efficiency and integration enable, for the first time, economic production of feed streams that could profoundly improve process economics for downstream cellulosic bioproducts.
      PubDate: 2017-04-13T10:00:24.09814-05:0
      DOI: 10.1002/cssc.201700183
       
  • Production of Biomass-Based Automotive Lubricants via Reductive
           Etherification
    • Authors: Alexis T. Bell; Deepak Jadhav, Adam A. Grippo, Sankaranaryanapillai Shyles, Amit A. Gokhale, John Redshaw
      Abstract: Growing concern with the effects of CO2 emissions due to the combustion of petroleum-based transportation fuels has motivated the search for means to increase engine efficiency. The discovery of ethers with low viscosity presents an important opportunity to improve engine efficiency and fuel economy. We show here a strategy for the catalytic synthesis of such ethers via reductive etherification/O-alkylation of alcohols using building blocks that can be sourced from biomass. We find that long chain branched ethers have several properties that make them superior lubricants to the mineral oil and synthetic base oils used today. These ethers provide a class of potentially renewable alternatives to conventional lubricants produced from petroleum and may contribute to the reduction of greenhouse gases associated with vehicle emissions.
      PubDate: 2017-04-12T22:17:36.460086-05:
      DOI: 10.1002/cssc.201700427
       
  • Environmental impact of ionic liquids: an overview of recent
           (eco)toxicological and (bio)degradability literature
    • Authors: M. Lúcia MFS Saraiva; Susana Costa, Paula Pinto, Ana Azevedo
      Abstract: This review aim integrating the more recent and pertinent available data on ionic liquids (bio)degradability and toxicity for a global and critical analysis and on a conscious use of these compounds at a large scale hereafter. The integrated data will enabe to focus on the recognition of toxicophores and on the way the community has been dealing with it, aiming real greener and safer ionic liquids. Also an update of the most recent biotic and abiotic methods developed to overcome some of these challenges issues will be presented. The review structure aims a representation of a potential sequence of events that can occur with ionic liquids discharge into the environment and the potential long-term consequences. Ionic liquids toxicity data published since 2010 has been compiled and is presented in appendix.
      PubDate: 2017-04-10T09:20:46.719117-05:
      DOI: 10.1002/cssc.201700261
       
  • Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for
           Efficient Continuous-Flow Nanocatalysis
    • Authors: Hirotaka Koga; Naoko Namba, Tsukasa Takahashi, Masaya Nogi, Yuta Nishina
      Abstract: Continuous-flow nanocatalysis by metal nanoparticle (NP) catalyst-anchored flow reactors has recently provided an excellent platform for effective chemical manufacturing. However, there has been limited progress in porous structure design and recycling systems for metal NP-anchored flow reactors to create more efficient and sustainable catalytic processes. Here, we renovated traditional paper as an efficient, recyclable, and renewable flow reactor by tailoring the ultra-structures of wood pulp. The 'paper reactor' offers hierarchically interconnected micro/nanoscale pores for efficient access of reactants to catalysts. In continuous-flow catalytic reduction of 4-nitrophenol, a gold NP-anchored paper reactor with the tailored micro/nanopores provided higher reaction efficiency than state-of-the-art flow reactors. Successful recycling and renewing of the paper reactors were also demonstrated. Our strategy offers potential for highly efficient and truly sustainable chemical manufacturing.
      PubDate: 2017-04-10T07:31:11.750831-05:
      DOI: 10.1002/cssc.201700576
       
  • Lignin Hydrogenolysis: Improving Lignin Disassembly through Formaldehyde
           Stabilization
    • Authors: Markus Kärkäs
      Abstract: Lignocellulosic biomass is available in large quantities and constitutes an attractive feedstock for the sustainable production of bulk and fine chemicals. While methods have been established for conversion of the cellulosic fractions, valorization of lignin has proven to be challenging. The difficulty in disassembling lignin originates from its heterogeneous structure and its propensity to undergo skeletal rearrangements and condensation reactions during biorefinery fractionation or biomass pretreatment processes. A strategy for hindering the generation of these resistive interunit linkages during biomass pretreatment has now been devised using formaldehyde as a stabilizing agent. The developed method when combined with Ru/C-catalyzed hydrogenolysis allows for efficient disassembly of all three biomass fractions―cellulose, hemicellulose and lignin―and suggests that lignin upgrading can be integrated into prevailing biorefinery schemes.
      PubDate: 2017-04-10T07:20:37.350301-05:
      DOI: 10.1002/cssc.201700436
       
  • Role of Alumina Basicity in CO2 Uptake in 3-Aminopropylsilyl-grafted
           Alumina Adsorbents
    • Authors: Matthew E Potter; Kyeong Min Cho, Jason L Lee, Christopher W Jones
      Abstract: Oxide-supported amine materials are widely known to be effective CO2 sorbents under simulated flue gas and direct air capture conditions. Most work has focused on amine species loaded onto porous silica supports, though potential stability advantages may be offered through use of porous alumina supports. Unlike silica materials, which are comparably inert, porous alumina materials can be tuned to have substantial acidity and/or basicity. Owing to their amphoteric nature, alumina supports play a more active role in CO2 sorption than silica supports, potentially directly participating in the adsorption process. In this work, primary amines associated with 3-aminopropyltriethoxysilane are grafted onto two different mesoporous alumina materials having different levels of basicity. Adsorbent materials with different amine loadings are prepared, and the CO2 adsorption behavior of similar amines on the two alumina supports are demonstrated to behave differently. At low amine loadings, the inherent properties of the support surface play a significant role, whereas at high amine loadings, when the alumina surface is effectively blocked, the sorbents prepared on the two supports behave similarly. At high amine loadings, amine-CO2-amine interactions are shown to dominate, leading to adsorbed species that appear similar to the species formed over silica supported amine materials.
      PubDate: 2017-04-07T08:21:07.585019-05:
      DOI: 10.1002/cssc.201700115
       
  • Simple and Effective Catalyst Separation by Novel CO2-induced Switchable
           Organocatalysts
    • Authors: Julia Großeheilmann; Udo Kragl
      Abstract: CO2-induced switchable tertiary amine-based organocatalysts were investigated for an efficient catalyst and product separation by its different partitioning between an organic and carbonated water phase. In this case study, the switching ability of 8 tertiary amine-based catalysts between the organic and water phase by addition or removal of CO2 was investigated. Here, the catalyst switched both nearly completely (99.9%) into the aqueous phase by addition of CO2 and effectively back into the organic phase (99.3%) by expelling CO2. With this technique, the organocatalyst was successfully recovered and reused for twelve times without significant loss of activity (up to 90% ee) for the asymmetric nitroaldol (Henry) reaction. After the first catalyst switch, evaporation of the solvent affords the product in 98% purity without any further purification steps.
      PubDate: 2017-04-07T04:23:21.487216-05:
      DOI: 10.1002/cssc.201700491
       
  • High Electrochemical Performance of Three-Dimensional Network Structured
           Crumpled Graphene/Carbon Nanotube/Polyaniline Composites for
           Supercapacitors
    • Authors: Eun Hee Jo; Hee Dong Jang, Hankwon Chang, Sun Kyung Kim, Ji-Hyuk Choi, Cong Min Lee
      Abstract: Crumpled graphene (CGR) is considered as a promising supercapacitor material toward high power and energy density because it could overcome disadvantages of two-dimensional (2D) GR sheets such as aggregation during electrode fabrication process, reduction of the available surface area and limitation of the electron and ion transport. Even though CGR showed good results, carbon materials are limited in terms of their capacitance performance. Here, we report highly enhanced supercapacitor materials by fabricating a three-dimensional (3D) composite composed of CGR, carbon nanotube (CNT), and polyaniline (PANI). The CNT increased the basal spacing and bridged the defects for electron transfer between the GR sheets in CGR. Polyaniline (PANI) can enhance the rate of conduction of electrons and offer high pseudocapacitance originating from its redox reactions. The synergistic effect of CNT and PANI may also result in a higher electrochemical capacitance and better stability than each individual component as electrode materials for supercapacitors in a two electrode system. More importantly, the performance of the supercapacitors can be further enhanced by employing 2D GR as the binder for the composite electrodes, resulting in specific capacitance of 456 F/g, rate capability of 89%, and cyclic stability of 97% after 1000 cycles.
      PubDate: 2017-04-06T09:25:47.82402-05:0
      DOI: 10.1002/cssc.201700212
       
  • Facile synthesis of rod-like Cu2-xSe and insight into its improved lithium
           storage property
    • Authors: He Li; Jiali Jiang, Feng Wang, Jianxing Huang, Yunhui Wang, Yiyong Zhang, Jinbao Zhao
      Abstract: A rod-like Cu2-xSe is synthesized via a facile water evaporation process. The electrochemical reaction mechanism is investigated with ex-situ X-ray diffraction (XRD) test. By adopting ether-based electrolyte instead of carbonate-based electrolyte, the electrochemical performance of Cu2-xSe electrodes improves significantly. The Cu2-xSe electrodes exhibit outstanding cycle performance, after 1000 cycles, 160 mAh g-1 can be maintained with the retention of 80.3 %. At current density of 100, 200, 500 and 1000 mA g-1, the capacity of Cu2-xSe/Li battery is 208, 202, 200 and 198 mAh g-1, respectively, showing excellent rate capability. The 4-probe conductivity measurements along with electrochemical impendence spectroscopy (EIS) and cyclic voltammetry (CV) tests illustrate that the Cu2-xSe electrodes display high specific conductivity and impressive lithium ion diffusion rate, which makes the Cu2-xSe to be a promising anode material for lithium ion batteries.
      PubDate: 2017-04-06T08:20:40.684259-05:
      DOI: 10.1002/cssc.201700317
       
  • SiW12-TiO2 mesoporous layer in favor of enhancing electron extraction
           efficiency and conductivity in perovskite solar cells
    • Authors: Guohua Dong; Tengling Ye, Yulin Yang, Li Sheng, Debin Xia, Junhai Wang, Xiao Fan, Ruiqing Fan
      Abstract: High quality electron transport layer (ETL) with superior optical and electrical properties is an essential part in high efficient perovskite solar cells (PSCs). In this work, SiW12-TiO2 mesoporous film is prepared by a facile one-step spin-coating deposition method and successfully applied as ETL in PSCs. Compared with pristine TiO2 based PSC, the SiW12-TiO2 based one shows a remarkable enhanced power conversion efficiency (PCE) from 12.00% to 14.66%, which is due to the higher conductivity, electron extraction efficiency and well-matched energy level alignment of SiW12-TiO2 film. Besides, the SiW12-TiO2 based device also shows a good long-time stability in an ambient environment. This work demonstrates that using Polyoxometalates (POMs) to modify the metal oxide semiconductor is an effective approach for the further enhancing the performance of PSCs.
      PubDate: 2017-04-05T21:25:55.445733-05:
      DOI: 10.1002/cssc.201700290
       
  • Composite Electrolyte for All-Solid-State Lithium Batteries:
           Low-Temperature Fabrication and Conductivity Enhancement
    • Authors: Sang-Don Lee; Kyu-Nam Jung, Hyeongil Kim, Hyun-Seop Shin, Seung-Wan Song, Min-Sik Park, Jong-Won Lee
      Abstract: All-solid-state lithium batteries offer notable advantages over conventional Li–ion batteries with liquid electrolytes in terms of energy density, stability, and safety. To realize this technology, it is critical to develop highly reliable solid-state inorganic electrolytes with high ionic conductivities and adequate processability. Li1+xAlxTi2−x(PO4)3 (LATP) with a NASICON (Na superionic conductor)-like structure is regarded as a potential solid electrolyte, owing to its high “bulk” conductivity (ca. 10−3 S cm−1) and excellent stability against air and moisture. However, the solid LATP electrolyte still suffers from a low “total” conductivity, mainly owing to the blocking effect of grain boundaries to Li+ conduction. In this study, an LATP–Bi2O3 composite solid electrolyte shows very high total conductivity (9.4×10−4 S cm−1) at room temperature. Bi2O3 acts as a microstructural modifier to effectively reduce the fabrication temperature of the electrolyte and to enhance its ionic conductivity. Bi2O3 promotes the densification of the LATP electrolyte, thereby improving its structural integrity, and at the same time, it facilitates Li+ conduction, leading to reduced grain-boundary resistance. The feasibility of the LATP–Bi2O3 composite electrolyte in all-solid-state Li batteries is also examined in this study.Superionic conductivity: LATP–Bi2O3 composite solid electrolyte (LATP=Li1+xAlxTi2−x(PO4)3) shows very high total conductivity (9.4×10−4 S cm−1) at room temperature. The Bi2O3 acts as a microstructural modifier to effectively reduce the fabrication temperature and promote the densification of the LATP electrolyte, thereby improving its structural integrity and ionic conductivity.
      PubDate: 2017-04-05T08:21:52.89341-05:0
      DOI: 10.1002/cssc.201700104
       
  • Glycidol, a valuable substrate for MAGEs synthesis: a simplified life
           cycle approach
    • Authors: Maria Ricciardi; Fabrizio Passarini, Ivano Vassura, Antonio Proto, Carmine Capacchione, Raffaele Cucciniello, Daniele Cespi
      Abstract: The disposal of any waste by recovering it within the production plant represents the ultimate goal of every bio-refinery. In this scenario, the selective preparation of monoalkyl glyceryl ethers (MAGEs) starting from glycidol, obtained as by-product in the epichlorohydrin production plant, represents a very promising strategy. Here we report the synthesis of MAGEs through the reaction of glycidol with alcohols catalyzed by a green homogeneous Lewis acids catalyst, such as BiIII triflate, under very mild reaction conditions. In order to evaluate the green potential of the proposed alternative, a simplified life cycle approach was followed by comparing the environmental performance of the proposed innovative route to prepare MAGEs with that of the most investigated pathway from glycerol. A considerable reduction of all the impact categories considered was observed in our experimental conditions, suggesting that the glycidol-to-MAGEs route can be a valuable integration to the glycerol-to-MAGEs chain. Thanks to the use of primary data within the LCA model, the results achieved are a very good approximation of the real case.
      PubDate: 2017-04-04T10:20:30.563531-05:
      DOI: 10.1002/cssc.201700525
       
  • Zeolites as sustainable catalysts for the selective synthesis of renewable
           bisphenols from lignin-derived monomers
    • Authors: Paola Ferrini; Steven-Friso Koelewijn, Joost Van Aelst, Nicolas Nuttens, Bert F. Sels
      Abstract: Alternative bio-based bisphenols from lignocellulosic biomass are not only favorable to reduce the environmental impact of current petroleum-derived plastics, but they can be simultaneously beneficial for health issues related to bisphenol A (BPA). Additionally, conventional BPA synthesis entails a large excess of unrecoverable homogeneous acid catalyst (e.g. HCl) or unrecyclable thermolabile sulfonated resins. In this report, we propose zeolites as recoverable and thermally stable solid acids for the Brønsted acid catalyzed condensation between 4-methylguaiacol and formaldehyde to selectively produce renewable bisphenols. It is found that the Brønsted acid site density plays a pivotal role for catalyst performances. In particular, the cheap and environmentally friendly FAU 40 exhibits outstanding activity (TOF 496 h-1) and selectivity (>95%), outperforming even the best benchmark catalyst. Additionally, the zeolite can be easily recycled without activity loss after regeneration by coke burn-off. The catalytic zeolite system seems very promising also for other lignin-derived alkylphenols, alkylguaiacols and alkylsyringols.
      PubDate: 2017-04-04T08:20:32.703852-05:
      DOI: 10.1002/cssc.201700338
       
  • Nitrogen Fixation by Gliding Arc Plasma: Better Insight by Chemical
           Kinetics Modelling
    • Authors: Weizong Wang; Bhaskar Patil, Stjin Heijkers, Volker Hessel, Annemie Bogaerts
      Abstract: The conversion of atmospheric nitrogen into valuable compounds, that is, so-called nitrogen fixation, is gaining increased interest, owing to the essential role in the nitrogen cycle of the biosphere. Plasma technology, and more specifically gliding arc plasma, has great potential in this area, but little is known about the underlying mechanisms. Therefore, we developed a detailed chemical kinetics model for a pulsed-power gliding-arc reactor operating at atmospheric pressure for nitrogen oxide synthesis. Experiments are performed to validate the model and reasonable agreement is reached between the calculated and measured NO and NO2 yields and the corresponding energy efficiency for NOx formation for different N2/O2 ratios, indicating that the model can provide a realistic picture of the plasma chemistry. Therefore, we can use the model to investigate the reaction pathways for the formation and loss of NOx. The results indicate that vibrational excitation of N2 in the gliding arc contributes significantly to activating the N2 molecules, and leads to an energy efficient way of NOx production, compared to the thermal process. Based on the underlying chemistry, the model allows us to propose solutions on how to further improve the NOx formation by gliding arc technology. Although the energy efficiency of the gliding-arc-based nitrogen fixation process at the present stage is not comparable to the world-scale Haber–Bosch process, we believe our study helps us to come up with more realistic scenarios of entering a cutting-edge innovation in new business cases for the decentralised production of fertilisers for agriculture, in which low-temperature plasma technology might play an important role.Fixation models: Nitrogen fixation is gaining increasing interest owing to its essential role in the nitrogen cycle of the biosphere. Gliding arc plasma has great potential for this purpose, however, the understanding of the underlying mechanisms is very limited. This work presents an extensive study elucidating the plasma chemistry by a combination of experiments and computations to provide the necessary insights for improving gliding arc based NOx synthesis.
      PubDate: 2017-04-04T03:01:27.560729-05:
      DOI: 10.1002/cssc.201700095
       
  • Dendrite Suppression by Synergistic Combination of Solid Polymer
           Electrolyte Crosslinked with Natural Terpenes and Lithium Powder Anode for
           Lithium Metal Batteries
    • Authors: Jimin Shim; Jae Won Lee, Ki Yoon Bae, Hee Joong Kim, Woo Young Yoon, Jong-Chan Lee
      Abstract: Lithium metal anode has fundamental problems concerning formation and growth of lithium dendrites which prevents practical applications of next generation of high-capacity lithium metal batteries. The synergistic combination of solid polymer electrolyte (SPE) crosslinked with naturally occurring terpenes and lithium powder anode is promising solution to resolve the dendrite issues by substituting conventional liquid electrolyte/separator and lithium foil anode system. A series of SPEs based on polysiloxane crosslinked with natural terpenes are prepared by facile thiol-ene click reaction under mild condition and structural effect of terpene crosslinkers on electrochemical properties is studied. Lithium powder with large surface area is prepared by droplet emulsion technique (DET) and used as anode materials. The effect of physical state of electrolyte (solid/liquid) and morphology of lithium metal anode (powder/foil) on dendrite growth behavior is systematically studied. The synergistic combination of SPE and lithium powder anode suggests effective solution to suppress the dendrite growth due to formation of stable solid electrolyte interphase (SEI) layer and delocalized current density.
      PubDate: 2017-04-03T21:22:19.406622-05:
      DOI: 10.1002/cssc.201700408
       
  • Atomically Altered Hematite for Highly Efficient Perovskite Tandem Water
           Splitting Devices
    • Authors: Gurudayal Gurudayal; Rohit Abraham John, Pablo P Boix, Chenyi Yi, Chen Shi, Mary C Scott, Sjoerd A Veldhuis, Andrew M Minor, Shaik M Zakeer, Lydia Wong, Michael Graetzel, Nripan Mathews
      Abstract: Photoelectrochemical (PEC) cells are attractive for storing solar energy in chemical bonds through cleaving of water into oxygen and hydrogen. Although hematite (a-Fe2O3) is a promising photoanode material due to its chemical stability, suitable band gap, low cost and environmental friendliness, its performance is limited by short carrier lifetimes, poor conductivity and sluggish kinetics leading to low (solar-to-hydrogen) STH efficiency. Herein, we combine solution based hydrothermal growth and a post-growth surface exposure through atomic layer deposition (ALD) to show a dramatic enhancement of the efficiency for water photolysis. These modified photoanodes show a high photocurrent of 3.12 mAcm-2 at 1.23 V vs. RHE, (> 5 times higher than Fe2O3) and a plateau photocurrent of 4.5 mAcm-2 at 1.5 V vs. RHE. We demonstrate that thesephotoanodes in tandem with a CH3NH3PbI3 perovskite solar cell achieves overall unassisted water splitting with an STH conversion efficiency of 3.4%, constituting a new benchmark for hematite based tandem systems.
      PubDate: 2017-04-02T21:21:09.827304-05:
      DOI: 10.1002/cssc.201700159
       
  • Greener Synthesis of D-pi-A Organic Sensitizers via Cu-Catalyzed Direct
           Arylations: Development of Sn- & Pd-Free Process for Dye-Sensitized Solar
           Cells
    • Authors: Jiung-Huai Huang; Po-Han Lin, Wei-Ming Li, Kun-Mu Lee, Ching-Yuan Liu
      Abstract: A variety of D-pi-A type functional organic dyes have been facilely synthesized via direct C-H arylations using inexpensive copper salts as catalyst. Under well-optimized reaction conditions, a broad substrate scope with good functional group compatibility was achieved. Based on this synthetic strategy, we designed and prepared three new dye sensitizers (CYL-5~7) that were fabricated as dye-sensitized solar cells (DSSCs). Photovoltaic characterizations showed that these devices gave a Voc of 0.65~0.75 V, a Jsc of 5.90~12.60 mA/cm2, and a FF of 65.6~76.9%, corresponding to the power conversion efficiency (PCE) of 2.95~6.20%. This work represents the first example using Cu-catalyzed C-H arylations as step-saving and Sn-free synthesis of various precursor dyes for DSSCs applications.
      PubDate: 2017-03-31T00:20:30.321848-05:
      DOI: 10.1002/cssc.201700421
       
  • Electrospinning Hetero-Nanofibers of Fe3C-Mo2C/Nitrogen-Doped-Carbon as
           Efficient Electrocatalysts for Hydrogen Evolution
    • Authors: Huanlei Lin; Wenbiao Zhang, Zhangping Shi, Minwei Che, Xiang Yu, Yi Tang, Qingsheng Gao
      Abstract: Heterostructured electrocatalysts with multiple active components are expected to synchronously address the two elementary steps in hydrogen evolution reactions (HER), which require varied hydrogen binding strength on catalyst surface. Herein, electrospinning followed by a pyrolysis is introduced to design Fe3C-Mo2C/nitrogen-doped carbon (Fe3C-Mo2C/NC) hetero-nanofibers (HNFs) with tuneable composition, accomplishing the abundant Fe3C-Mo2C hetero-interfaces for synergy in electrocatalysis. Thanks to the strong hydrogen binding on Mo2C and the relatively weak one on Fe3C, the hetero-interfaces of Fe3C-Mo2C remarkably promote HER kinetics and intrinsic activity. Meanwhile, the loose and porous N-doped carbon matrix, as a result of Fe-catalyzed carbonization, ensures the fast transport of electrolytes and electrons, minimizing the limitation by diffusion. As expected, the optimal Fe3C-Mo2C/NC HNFs afford a low overpotential of 116 mV at a current density of -10 mA cm-2 and striking kinetics metrics (onset overpotential: 42 mV, Tafel slope: 43 mV dec-1) in 0.5 M H2SO4, outperforming most of recently-reported noble-metal-free electrocatalysts.
      PubDate: 2017-03-30T06:20:42.487617-05:
      DOI: 10.1002/cssc.201700207
       
  • Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells
    • Authors: Yinshi Li; Xianda Sun, Ying Feng
      Abstract: Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction hinder the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenzimidazole-membrane-based direct formate fuel cell (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 °C. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm−2, an order of magnitude higher than both alkaline direct ethanol fuel cells and alkaline direct methanol fuel cells, mainly because the hydrolysis of formate provides enough OH− ions for formate oxidation reaction. It was also found that this hydroxide self-feeding high-temperature alkaline DFFC shows a stable 100 min constant-current discharge at 90 °C, proving the conceptual feasibility.No additional alkali: A high-temperature alkaline direct formate fuel cell is proposed owing to the fact that formate hydrolysis can provide hydroxide to meet the requirement of formate oxidation reaction. The proof-of-concept fuel cell shows a stable 100 min constant-current discharge in the absence of additional hydroxide at 90 °C, proving the feasibility of hydroxide self-feeding high-temperature alkaline fuel cells.
      PubDate: 2017-03-30T03:26:11.399369-05:
      DOI: 10.1002/cssc.201700228
       
  • A Simple and Mild Approach for the Synthesis of p-Xylene from Bio-Based
           2,5-Dimethyfuran by Using Metal Triflates
    • Authors: Lingli Ni; Jiayu Xin, Huixian Dong, Xingmei Lu, Xiaomin Liu, Suojiang Zhang
      Abstract: The production of aromatic platform chemicals from biomass-derived feedstocks is of considerable importance in biomass conversion. However, the development of effective routes with simple steps and under mild conditions is still challenging. In this work, we report an original route for the direct synthesis of p-xylene from 2,5-dimethylfuran and acrylic acid catalyzed by scandium(III) triflate (Sc(OTf)3) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim]NTf2) under mild conditions. An overall 63 % selectivity towards p-xylene and 78 % selectivity towards aromatics were obtained at 90 % conversion of 2,5-dimethylfuran by enhancing the dehydration and introducing an extra one-pot decarboxylation step. Furthermore, various dienes and dienophiles were employed as reactants to extend the substrate scope. The aromatic compounds were obtained in moderate yields, which proved the potential of the method to be a generic approach for the conversion of bio-based furanics into renewable aromatics.A triflate synthesis of xylene: Renewable p-xylene is directly synthesized from biomass-derived 2,5-dimethylfuran and acrylic acid over scandium(III) triflate (Sc(OTf)3) and H3PO4 in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim]NTf2) under mild conditions. A subsequent one-pot decarboxylation step results in an overall 63 % selectivity towards p-xylene at 90 % conversion of 2,5-dimethylfuran.
      PubDate: 2017-03-30T03:25:40.378183-05:
      DOI: 10.1002/cssc.201700020
       
  • Unravelling Some of the Key Transformations in the Hydrothermal
           Liquefaction of Lignin
    • Authors: Matthew Yuk-Yu Lui; Bun Chan, Alexander Yuen, Anthony Masters, Alejandro Montoya, Thomas Maschmeyer
      Abstract: Using both experimental and computational methods, focusing on intermediates and model compounds, we elucidate some of the main features of the reaction mechanisms that operate during the hydrothermal processing of lignin. We propose key reaction pathways and their connection to different structural features of lignin. Under neutral conditions, subcritical water was demonstrated to act as a bifunctional acid/base catalyst for the dissection of lignin structures. In a complex web of mutually dependent interactions, guaiacyl units within lignin were shown to significantly affect overall lignin reactivity.
      PubDate: 2017-03-29T23:20:22.133767-05:
      DOI: 10.1002/cssc.201700528
       
  • Direct Access to Primary Amines and Particle Morphology Control in
           Nanoporous CO2 Sorbents
    • Authors: Nesibe A. Dogan; Ercan Ozdemir, Cafer T. Yavuz
      Abstract: Chemical tuning of nanoporous, solid sorbents for ideal CO2 binding requires unhindered amine functional groups on the pore walls. Although common for soluble organics, post-synthetic reduction of nitriles in porous networks often fails due to insufficient and irreversible metal hydride penetration. In this study, a nanoporous network with pendant nitrile groups, microsphere morphology was synthesized in large scale. The hollow microspheres were easily decorated with primary amines through in situ reduction by widely available boranes. The CO2 capture capacity of the modified sorbent was increased to up to four times that of the starting nanoporous network with a high heat of adsorption (98 kJ mol−1). The surface area can be easily tuned between 1 and 354 m2 g−1. The average particle size (ca. 50 μm) is also quite suitable for CO2 capture applications, such as those with fluidized beds requiring spheres of micron sizes.Smooth access: Nitrile groups in linear polymers can be readily reduced in solution. However, this reduction is challenging in insoluble network polymers, since reducing agents cannot easily access the nitrile groups. The porous polymers reported in this work undergo complete reduction of nitrile pendant groups into amines (−NH2) without sacrificing porosity.
      PubDate: 2017-03-29T09:46:12.330725-05:
      DOI: 10.1002/cssc.201700190
       
  • Poly(4-vinylpyridine)-based Interfacial Passivation to Enhance Voltage and
           Moisture Stability of Lead Halide Perovskite Solar Cells
    • Authors: Tsutomu Miyasaka; Bhumika Chaudhary, Ashish Kulkarni, Ajay Kumar Jena, Masashi Ikegami, Yosuke Udagawa, Hideyuki Kunugita, Kazuhiro Ema
      Abstract: It is well known that the surface trap states and electronic disorders in the solution-processed CH3NH3PbI3 perovskite film affect the solar cell performance significantly and moisture sensitivity of photo-active perovskite material limits its practical applications. Herein, we show surface modification of perovskite film with a solution-processable hydrophobic polymer namely poly(4-vinylpyridine) (PVP), which passivates the under-coordinated lead (Pb) atoms (on the surface of perovskite) via its pyridine Lewis base side chains and thereby eliminates surface trap states and non-radiative recombination. Besides, it acts as an electron barrier between the perovskite and hole transport layer (HTL) to reduce interfacial charge recombination, which led to improvement in open-circuit voltage (Voc) by 120 to 160 mV while the standard cell fabricated in same conditions showed Voc as low as 0.9 V due to dominating interfacial recombination processes. Consequently, power conversion efficiency increased by 3% to 5% in the polymer modified devices (PCE=15%) with Voc more than 1.05V and hysteresis-less J-V curves. Advantageously, hydrophobicity of the polymer chain was found to protect the perovskite surface from moisture and improved stability of the non-encapsulated cells, which retained their device performance up to 30 days of exposure to open atmosphere (50% humidity).
      PubDate: 2017-03-29T06:50:22.871626-05:
      DOI: 10.1002/cssc.201700271
       
  • Self-assembly of Spinel Nano-crystals into Mesoporous Spheres as
           Bi-functionally Active Oxygen Reduction and Evolution Electrocatalysts
    • Authors: Dong Un Lee; Jingde Li, Moon Gyu Park, Min Ho Seo, Wook Ahn, Ian Stadelmann, Luis Ricardez-Sandoval, Zhongwei Chen
      Abstract: The present work introduces spinel oxide nano-crystals self-assembled into mesoporous spheres that are bi-functionally active towards catalyzing both oxygen reduction reaction (ORR), and oxygen evolution reaction (OER). The electrochemical evaluation reveals that (Ni,Co)3O4 demonstrates significantly positive shifted ORR on-set and half-wave potentials (-0.127 and -0.292 V vs. SCE, respectively), while Co3O4 results in a negative shifted OER potential (0.65 V vs. SCE) measured at 10 mA cm-2. Based on the DFT analysis, the potential at which all oxygen intermediate reactions proceed spontaneously is the highest for (Ni,Co)3O4 (U = 0.66 eV) during ORR, while it is the lowest for Co3O4 (U = 2.09 eV) during OER. The high ORR activity of (Ni,Co)3O4 is attributed to the enhanced electrical conductivity of the spinel lattice, while the high OER activity of Co3O4 is attributed to relatively weak adsorption energy promoting rapid release of evolved oxygen.
      PubDate: 2017-03-29T03:25:22.543159-05:
      DOI: 10.1002/cssc.201700369
       
  • Bifunctional Molybdenum Polyoxometalates for the Combined
           Hydrodeoxygenation and Alkylation of Lignin-derived Model Phenolics
    • Authors: Eric Michael Anderson; Anthony Crisci, Karthick Murugappan, Yuriy Roman-Leshkov
      Abstract: Reductive catalytic fractionation of biomass has recently emerged as a powerful lignin extraction and depolymerization method to produce monomeric aromatic oxygenates in high yields. Here, bifunctional molybdenum-based polyoxometalates supported on titania (POM/TiO2) are shown to promote tandem hydrodeoxygenation (HDO) and alkylation reactions, converting lignin-derived oxygenated aromatics into alkylated benzenes and alkylated phenols in high yields. In particular, anisole and 4 propylguaiacol were used as model compounds for this gas-phase study using a packed bed flow reactor. For anisole, 30% selectivity for alkylated aromatic compounds with an overall 72% selectivity for HDO at 82% anisole conversion was observed over H3PMo12O40/TiO2 at 7 h on stream. Under similar conditions, 4-propylguaiacol was mainly converted into 4 propylphenol and alkylated 4-propylphenols with a selectivity to alkylated 4 propylphenols of 42% with a total HDO selectivity to 4 propylbenzene and alkylated 4 propylbenzenes of 4% at 92% conversion (7 h on stream). Higher catalyst loadings pushed the 4-propylguaiacol conversion to 100% and resulted in a higher selectivity to propylbenzene of 41%, alkylated aromatics of 21% and alkylated phenols of 17%. The reactivity studies coupled with catalyst characterization revealed that Lewis acid sites act synergistically with neighboring Brønsted acid sites to simultaneously promote alkylation and HDO activity.
      PubDate: 2017-03-28T04:25:32.031986-05:
      DOI: 10.1002/cssc.201700297
       
  • Expeditious and Solvent-Free Nickel-Catalyzed C‒H Arylation of
           Arenes and Indoles
    • Authors: Rahul A Jagtap; Vineeta Soni, Benudhar Punji
      Abstract: An efficient solvent-free nickel-catalyzed method for the C‒H bond arylation of arenes and indoles is described that proceeds expeditiously via chelation-assistance. The reaction is highly selective for mono-arylation, and tolerates sensitive and structurally diverse functionalities, such as halides, ethers, amines, indole, pyrrole and carbazole. This reaction represents the first example of nickel-catalyzed C‒H arylation by mono-chelate assistance, and symbolizes a rare precedent of solvent-free C‒H arylation. Mechanistic investigations by various controlled reactions, kinetic studies and deuterium labelling experiments suggest that the arylation follows a single electron transfer (SET) pathway involving the turnover-limiting C‒H nickelation process.
      PubDate: 2017-03-27T00:25:35.086684-05:
      DOI: 10.1002/cssc.201700321
       
  • Stable Ni particles through structural reversibility in La-Fe-Ni
           perovskite type metal oxide catalysts
    • Authors: Patrick Steiger; Renaud Delmelle, Debora Foppiano, Lorenz Holzer, Andre Heel, Maarten Nachtegaal, Oliver Kröcher, Davide Ferri
      Abstract: Perovskite-type oxides have shown the ability to reversibly segregate precious metals from their structure. This reversible segregation behavior was explored for a commonly used catalyst metal, Ni, to prevent Ni sintering, which is observed on most catalyst support materials. TPR, XRD, XAS, electron microscopy and catalytic activity tests were used to follow the extent of reversible Ni segregation. LaFe1 xNixO3±δ (0 ≤ x ≤ 0.2) was synthesized using a citrate based solution process. After reduction at 600°C metallic Ni particles were displayed on the perovskite surfaces, which showed to be active towards the hydrogenation of CO2. The overall Ni reducibility was proportional to the Ni content and increased from 35 % for x = 0.05 to 50 % for x = 0.2. Furthermore, Ni could be reversibly reincorporated into the perovskite lattice during reoxidation at 650 °C. This could be exploited for catalyst regeneration under conditions where impregnated materials such as Ni/LaFeO3±δ and Ni/Al2O3 suffer from sintering.
      PubDate: 2017-03-24T05:15:23.435528-05:
      DOI: 10.1002/cssc.201700358
       
  • Insights into the Mechanism of a Covalently-Linked Organic Dye-Cobaloxime
           Catalyst System for Dye Sensitized Solar Fuel Devices
    • Authors: Palas Baran Pati; Lei Zhang, Bertrand Philippe, Ricardo Fernández-Terán, Sareh Ahmadi, Lei Tian, Håkan Rensmo, Leif Hammarström, Haining Tian
      Abstract: A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photoelectrochemical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, they suggest that the dye adopt different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis in order to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on photocathode is eventually proposed on the basis of this study.
      PubDate: 2017-03-24T05:15:20.151556-05:
      DOI: 10.1002/cssc.201700285
       
  • WxC@C/NRGO Composite Derived from Polyoxotungstate/Conductive
           polypyrrole/Graphene as Efficient Electrocatalyst for Hydrogen Evolution
           Reaction
    • Authors: Ya-Qian Lan; Xiao-Li Wang, Yu-Jia Tang, Wei Huang, Chun-Hui Liu, Long-Zhang Dong, Shun-Li Li
      Abstract: Efficient hydrogen evolution reaction (HER) from water through electrocatalysis using cost-effective materials is critical to realize the clean hydrogen production. Herein, with controlling the structure and composition of polyoxotungstate/conductive polypyrrole/graphene (PCG) precursor precisely and followed by the temperature-programmed reaction, we developed a highly active and stable catalyst WxC@C/NRGO. The composite presents splendid performance towards HER in acidic media, with a small onset overpotential of 24 mV vs. RHE, a low Tafel slope of 58.4 mV dec-1, a low overpotential of 100 mV at 10 mA cm-2, and remarkable long-term cycle stability. This is one of the highest HER catalysts among the tungsten carbides-based materials ever reported.
      PubDate: 2017-03-23T22:05:40.118455-05:
      DOI: 10.1002/cssc.201700276
       
  • Pd-Metalated Conjugated Nanoporous Polycarbazoles for Additive-Free
           Cyanation of Aryl Halides: Boosting Catalytic Efficiency via Spatial
           Modulation
    • Authors: Shunmin Ding; Chengcheng Tian, Xiang Zhu, Carter W. Abney, Ziqi Tian, Bo Chen, Meijun Li, De-en Jiang, Ning Zhang, Sheng Dai
      Abstract: A novel spatial-modulation approach was developed to fabricate a new heterogeneous Pd-metalated nanoporous polymer for efficient and ligand-free cyanation of aryl halides. The resulting catalyst displays high activity in the synthesis of benzonitriles, including high product yield, excellent stability and recycle, and broad scope functional group tolerance.
      PubDate: 2017-03-23T07:49:32.942319-05:
      DOI: 10.1002/cssc.201700329
       
  • Designing Squaraines to Control Charge Injection and Recombination
           Processes in NiO-based Dye-Sensitized Solar Cells
    • Authors: Oliver Langmar; Davide Saccone, Anna Amat, Simona Fantacci, Guido Viscardi, Claudia Barolo, Ruben Costa, Dirk Michael Guldi
      Abstract: Herein, the synthesis of a novel family of squaraines (SQ) and their application in p-type dye-sensitized solar cells (DSSC) is presented. In particular, two sets of SQs were designed. The SQs have been characterized by using a joint theoretical, photophysical and electrochemical approach. Importantly, the presence of different central groups forces them into a frozen cis (dicyanovinyl group) or a trans (oxygen group) conformation. Based on the latter, the current work enables the direct comparison between cis and trans isomers, as well as the impact of a different number of anchors. Considering their electron accepting and light harvesting character they were tested in NiO-based DSSCs. Photocurrent-voltage, incident photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements were performed. By virtue of their different symmetry, stereochemistry, and number of carboxylic groups, altered adsorption behavior onto NiO electrodes, as well as diverse charge injection and charge recombination dynamics were noted under operation conditions. SQs with four linkers show the best balance between charge injection and recombination.. As a complement, we assembled tandem-DSSCs featuring SQ / NiO photocathodes and N719 / TiO2 photoanodes. The IPCE of the resulting tandem-DSSCs imply light harvesting throughout most of the visible part of the solar spectrum due to the complementary absorption of SQ and N719.
      PubDate: 2017-03-20T06:21:06.06418-05:0
      DOI: 10.1002/cssc.201700152
       
  • Eco-efficient synthesis of highly-porous CoCO3 anodes for Li+ and Na+
           storage using supercritical CO2 precursors
    • Authors: Hui-Ying Li; Chuan-Ming Tseng, Cheng-Hsien Yang, Tai-Chou Lee, Ching-Yuan Su, Chien-Te Hsieh, Jeng-Kuei Chang
      Abstract: An eco-efficient synthesis route of high-performance carbonate anodes for Li+ and Na+ batteries is developed. With supercritical CO2 (SCCO2) as the precursor, which has gas-like diffusivity, extremely low viscosity, and near-zero surface tension, CoCO3 particles are uniformly formed and tightly connected on graphene nanosheets (GNSs). This synthesis can be conducted at 50 °C, which is considerably lower than the temperature required for conventional preparation methods, minimizing energy consumption. The obtained CoCO3 particles (~20 nm in diameter), which have a unique interpenetrating porous structure, can increase the number of electroactive sites, promote electrolyte accessibility, shorten ion diffusion length, and readily accommodate the strain generated upon charging/discharging. With a reversible capacity of 1105 mAh g−1, the proposed CoCO3/GNS anode shows an excellent rate capability, as it is able to deliver 745 mAh g−1 in 7.5 min. More than 98% of the initial capacity can be retained after 200 cycles. These properties are clearly superior to those of previously reported CoCO3-based electrodes for Li+ storage, indicating the merit of our SCCO2 synthesis, which is facile, green, and easily scaled up for mass production.
      PubDate: 2017-03-20T04:20:43.663523-05:
      DOI: 10.1002/cssc.201700171
       
  • Metal Doping for Enhancing the Photoelectrochemical Behavior of LaFeO3
           Photocathodes
    • Authors: María Isabel Díez-García; Roberto Gómez
      Abstract: The development of tandem devices for water photosplitting requires finding photocathodic materials based on earth-abundant elements and showing long-term stability in aqueous electrolytes. Ternary metal oxides seem to be a viable option, among which perovskites stand out. In this context, transparent and compact LaFeO3 thin film electrodes have been prepared by sol-gel, both undoped and doped with metals (M) such as magnesium or zinc. Pristine electrodes support the development of cathodic photocurrents in 0.1 M NaOH aqueous solutions, particularly in the presence of oxygen, with an onset potential as high as 1.4 V vs. RHE. Doping with Mg or Zn leads to an important enhancement of the photocurrent, which peaks for a stoichiometry LaFe0.95M0.05O3 with a six-fold enhancement with respect to the pristine material. Such an improvement is attributed to an increase in both the density and mobility of the majority carriers, although a contribution of surface passivation cannot be excluded.
      PubDate: 2017-03-20T02:10:51.269277-05:
      DOI: 10.1002/cssc.201700166
       
  • Design Principles for Covalent Organic Frameworks in Energy Storage
           Applications
    • Authors: Sampath B Alahakoon; Christina M Thompson, Gino Occhialini, Ronald Alexander Smaldone
      Abstract: Covalent organic frameworks (COFs) are an exciting class of microporous materials that have been explored as energy storage materials for more than a decade. This review will discusses the efforts to develop these materials for applications in gas and electrical power storage. This review will also discuss some of the design strategies for developing the gas sorption properties of COFs and mechanistic studies on their formation.
      PubDate: 2017-03-16T21:40:28.994571-05:
      DOI: 10.1002/cssc.201700120
       
  • Reliable Performance Characterization of Mediated Photocatalytic
           Water-Splitting Half Reactions
    • Authors: Lihao Han; Meng Lin, Sophia Haussener
      Abstract: Photocatalytic approaches using two sets of semiconductor particles and a pair of redox-shuttle mediators are considered as a safe and economic solution for solar water splitting. Here, accurate experimental characterization techniques for photocatalytic half reactions are reported, investigating the gas as well as the liquid products. The methods are exemplified utilizing photocatalytic titania particles in an iron-based aqueous electrolyte for effective oxygen evolution and mediator reduction reactions under illumination. Several product characterization methods, including an optical oxygen sensor, pressure sensor, gas chromatography, and UV/Vis spectroscopy are used and compared for accurate, high-resolution gas-products and mediator conversion measurements. Advantages of each technique are discussed. A high Faraday efficiency of 97.5±2 % is calculated and the reaction rate limits are investigated.A closer look: Various reliable characterization methods for a photocatalytic reactor consisting of semiconductor particles and mediator shuttles are proposed. The method is exemplified utilizing photocatalytic titania particles in an iron-based aqueous electrolyte for effective oxygen evolution and mediator reduction reactions under illumination. Several product characterization methods, including an optical oxygen sensor, pressure sensor, gas chromatography, and UV/Vis spectroscopy are used and compared.
      PubDate: 2017-03-16T05:19:08.477796-05:
      DOI: 10.1002/cssc.201601901
       
  • Sulfur-doped porphyrinic carbon nanostructures synthesized by amorphous
           MoS2 for oxygen reduction reaction in an acid medium
    • Authors: Hyun-Suk Park; Sang-Beom Han, Da-Hee Kwak, Gyu-Ho Lee, In-Ae Choi, Do-Hyoung Kim, Kyeng-Bae Ma, Min-Cheol Kim, Kyung-Won Park
      Abstract: To develop doped carbon nanostructures as non-precious metal cathode catalysts, we synthesize the nanocomposites using SBA-15 and 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin-Fe(III) chloride with different ratios of amorphous MoS2 precursor. From various analyses, it was found that during the pyrolysis at 900 oC under an N2 atmosphere, the amorphous MoS2 precursor was decomposed into Mo and S, facilitating the formation of graphene sheet-like carbon with MoC and doping of sulfur in the carbon. Especially, in the case of Mo/S/C-10, most of the 10 wt% MoS2 precursor was decomposed, thus forming S-doped carbon which was grown on MoC phase without crystalline MoS2 phase. Furthermore, Mo/S/C-10 exhibited enhanced ORR performance (specific activity of 1.23 mA cm-2 at 0.9 V and half-wave potential of 0.864 V), compared to a commercial Pt catalyst, due to heteroatom-doped carbon nanostructure with a fairly high specific surface area. In the polarization curve of the unit cell measured at 80 oC under an ambient pressure, Mo/S/C-10 as a cathode catalyst exhibited a maximal power density of 314 mW cm-2 and current density of 280 mA cm-2 at 0.6 V.
      PubDate: 2017-03-15T00:40:59.517102-05:
      DOI: 10.1002/cssc.201700147
       
  • Iron-based electrodes meet water-based preparation, fluorine- free
           electrolyte and binder: a chance for more sustainable Li-ion
           batteries'
    • Authors: Mario Valvo; Anti Liivat, Henrik Eriksson, Cheuk-Wai Tai, Kristina Edström
      Abstract: Environmentally friendly and cost-effective Li-ion cells are fabricated with abundant, non-toxic LiFePO4 cathodes and Fe oxide anodes. A water-soluble alginate binder is used for coating both electrodes to reduce the environmental footprint. Critical reactivity of LiPF6-based electrolytes toward possible H2O traces in water-processed electrodes is overcome by using a LiBOB salt. The absence of fluorine in both electrolyte and binder is a cornerstone for improved cell chemistry and is demonstrated to result in stable battery operation. A dedicated approach to better exploit conversion-type anodes is also disclosed. The issue of large voltage hysteresis upon conversion/de-conversion is circumvented by operating iron oxide in a deeply lithiated Fe/Li2O form. Li-ion cells with energy efficiencies up to 92% are demonstrated when LiFePO4 is cycled versus such anodes prepared via a pre-lithiation procedure. These cells show an average energy efficiency of ≈90.66% and a mean coulombic efficiency of ≈99.65% over 320 cycles at current densities of 0.1, 0.2 and 0.3 mAcm-2, retaining nearly 100% of their initial discharge capacity and providing an unmatched operation potential of ≈2.85 V for this combination of active materials. No occurrence of Li-plating has been detected in three-electrode cells at charging rates of ≈5C. Excellent rate capabilities up to ≈30C are achieved thanks to the exploitation of size effects due to small Fe nanoparticles and their reactive boundaries.
      PubDate: 2017-03-10T15:40:35.362279-05:
      DOI: 10.1002/cssc.201700070
       
  • Nanostructured Silica-Titania Hybrid using Fibrous Nanosilica as
           Photocatalysts
    • Authors: Nisha Bayal; Rustam Singh, Vivek Polshettiwar
      Abstract: We have developed a novel method of fabricating active TiO2 photocatalysts by tuning the morphology of catalyst support. Sustainable solution phase TiO2 deposition on silica protocol is developed over complex and expensive atomic layer deposition technique. In general, catalytic activity decreases with increase in TiO2 loading on conventional mesoporous silica because of the loss of surface area due to blocking of pores. Notably, in the case of KCC-1 as a support, because of its open fibrous morphology, even at the highest TiO2 loading, a relatively large amount of surface area remained intact. This improved the accessibility of active sites, which increased the catalytic performance of KCC-1/TiO2 photocatalyst. Fibrous nanosilica supported titania is found to be a superior photocatalyst in terms of H2 generation (26.4 mmolh-1g-1TiO2) using UV light. This study may provide a new direction for photocatalyst development by morphology control of the support.
      PubDate: 2017-03-02T03:45:30.428997-05:
      DOI: 10.1002/cssc.201700135
       
  • Remarkably Efficient Microvawe-Assisted Cross-Metathesis of Lipids in
           Solvent Free Conditions
    • Authors: Aman Ullah; Muhammad Arshad
      Abstract: Catalytic transformation of renewable feed stocks into fine chemicals is in high demands and olefin metathesis is one of the sophisticated tools for biomass conversion. Nevertheless, the large scale viability of such processes depends on the conversion efficiency, energy efficiency, catalytic activity, selective conversion into desired products and environmental footprint of the process. Thus, conversions of renewables using simple, swift, and efficient methods are desirable. A microwave-assisted ethenolysis and alkenolysis (using 1-5 hexadiene) of canola oil and methyl esters derived from canola oil (COME) and waste/recycled cooking oil (WOME) was carried out using ruthenium based catalytic systems. A systematic study using 1st and 2nd generation Grubbs (G1, G2) and Hoveyda-Grubbs (HG1 & HG2) catalysts was carried out. Among all ruthenium catalysts, HG2 was found to be highly active in the range of 0.002-0.1 mol% loadings. The conversions proved to be highly efficient with outstanding values of turnover numbers (TONs) and turnover frequencies (TOFs). The TONs for ethenolysis of COME (~1.5 million), direct ethenolysis of canola oil (~0.6 million), more than 1 million for WOME and above 1.6 million for cross metathesis of 1,5-hexadiene with COME were achieved. The ethenolysis of commercial methyl oleate was also performed leading to TONs ~1.2 million and TOFs 20,300 s-1 under microwave conditions.
      PubDate: 2017-02-28T21:46:01.111823-05:
      DOI: 10.1002/cssc.201601824
       
  • Flexible Asymmetric Supercapacitors Based on Nitrogen-Doped Graphene
           Hydrogels with Embedded Nickel Hydroxide Nanoplates
    • Authors: Hao Xie; Shaochun Tang, Dongdong Li, Sascha Vongehr, Xiangkang Meng
      Pages: 2301 - 2308
      Abstract: To push the energy density limit of supercapacitors (SCs), new electrode materials with hierarchical nano-micron pore architectures are strongly desired. Graphene hydrogels that consist of 3 D porous frameworks have received particular attention but their capacitance is limited by electrical double layer capacitance. In this work, we report the rational design and fabrication of a composite hydrogel of N-doped graphene (NG) that contains embedded Ni(OH)2 nanoplates that is cut conveniently into films to serve as positive electrodes for flexible asymmetric solid-state SCs with NG hydrogel films as negative electrodes. The use of high-power ultrasound leads to hierarchically porous micron-scale sheets that consist of a highly interconnected 3 D NG network in which Ni(OH)2 nanoplates are well dispersed, which avoids the stacking of NG, Ni(OH)2, and their composites. The optimal SC device benefits from the compositional features and 3 D electrode architecture and has a high specific areal capacitance of 255 mF cm−2 at 1.0 mA cm−2 and a very stable, high output cell voltage of 1.45 V, which leads to an energy density of 80 μW h cm−2 even at a high power of 944 μW cm−2, considerably higher than that reported for similar devices. The devices exhibit a high rate capability and only 8 % capacitance loss over 10 000 charging cycles as well as excellent flexibility with no clear performance degradation under strong bending.Bend me, shape me: We report the fabrication of a new composite hydrogel of N-doped graphene (NG) that contains embedded Ni(OH)2 nanoplates. Asymmetric solid-state supercapacitors prepared from such hydrogel films as positive electrodes deliver high energy densities. The high output cell voltage allows a light-emitting diode to be operated with a single capacitor.
      PubDate: 2016-04-20T05:28:08.5687-05:00
      DOI: 10.1002/cssc.201600150
       
 
 
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