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  Subjects -> COMPUTER SCIENCE (Total: 1996 journals)
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COMPUTER SCIENCE (1162 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 13)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 23)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 9)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 12)
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: 14)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 5)
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: 21)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 8)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 9)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 11)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 25)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Advanced Engineering Materials     Hybrid Journal   (Followers: 26)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 16)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Computer Science : an International Journal     Open Access   (Followers: 14)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Human-Computer Interaction     Open Access   (Followers: 20)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 39)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 3)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 8)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 9)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 4)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 5)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 7)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
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: 1)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 13)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Computer Systems     Open Access   (Followers: 1)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 11)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 134)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 7)
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   (Followers: 1)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 4)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 11)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 272)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 33)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 128)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 2)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Capturing Intelligence     Full-text available via subscription  
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
Cell Communication and Signaling     Open Access   (Followers: 1)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access  
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 12)
Circuits and Systems     Open Access   (Followers: 16)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Communication Methods and Measures     Hybrid Journal   (Followers: 12)
Communication Theory     Hybrid Journal   (Followers: 20)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 54)
Communications of the Association for Information Systems     Open Access   (Followers: 18)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access  
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 15)
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: 30)
Computer     Full-text available via subscription   (Followers: 87)
Computer Aided Surgery     Hybrid Journal   (Followers: 3)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 7)
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: 21)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 10)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 1)
Computer Music Journal     Hybrid Journal   (Followers: 16)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computer Science and Information Technology     Open Access   (Followers: 12)
Computer Science Education     Hybrid Journal   (Followers: 13)
Computer Science Journal     Open Access   (Followers: 20)

        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  [1589 journals]
  • Highly Efficient Gas Phase Oxidation of Renewable Furfural to Maleic
           Anhydride over Plate VPO Catalyst
    • Authors: Yugen Zhang; Xiukai Li, Jogie Ko
      Abstract: Maleic anhydride (MAnh) and its acids are critical intermediates in chemical industry. The synthesis of maleic anhydride from renewable furfural is one of the most sought after processes in the field of sustainable chemistry. We report a plate vanadium phosphorous oxide (VPO) catalyst synthesized by a hydrothermal method with glucose as a green reducing agent for furfural oxidation to MAnh in gas phase. The plate VPOHT catalyst has a preferentially exposed 200 crystal plane and exhibited dramatically enhanced activity, selectivity and stability as compared to conventional VPO catalysts and other state-of-the-art catalytic systems. At 360 ºC reaction temperature with air as an oxidant, about 90% yield of MAnh was achieved at 10 vol% of furfural in the feed, a furfural concentration value that is much higher than those (< 2 vol%) reported for other catalytic systems. The catalyst showed good long term stability and there was no decrease in activity and selectivity for MAnh in the time-on-steam duration of 25 h. The high efficiency and catalyst stability established this system very prominent for the synthesis of maleic anhydride from renewable furfural.
      PubDate: 2017-12-15T04:51:18.845158-05:
      DOI: 10.1002/cssc.201701866
       
  • Heterojunction Engineering for High Efficiency Cesium-Formamidinium Double
           Cation Lead Halide Perovskite Solar Cells
    • Authors: Yihui Wu; Peng Wang, Shubo Wang, Zenghua Wang, Bing Cai, Xiaojia Zheng, Yu Chen, Ningyi Yuan, Jianning Ding, Wen-Hua Zhang
      Abstract: It is essential to minimize the interfacial trap states and improve the carrier collection for high efficiency perovskite solar cells (PSCs). Herein, we present a facile method to construct a p-type graded heterojunction (GHJ) in the normal PSCs by deploying a gradient distribution of hole-transporting materials (PTAA in this case) in the shallow perovskite layer. The formation of the GHJ structure facilitates charge transfer and collection, passivates interfacial trap states, thus delivering a power conversion efficiency (PCE) of 20.05% along with steady output efficiency of 19.3%, which is among the highest efficiencies for Cs-Formamidinium (Cs,FA) lead halide PSCs. Moreover, the unencapsulated devices based on these (Cs,FA) lead halide perovskites show excellent long-term stability, more than 95% of their initial PCE can be retained after 1440 h' storage under the ambient conditions. This study may provide an effective strategy to fabricate high efficiency PSCs with great stability.
      PubDate: 2017-12-15T03:04:59.929128-05:
      DOI: 10.1002/cssc.201702221
       
  • Sustainable carbon/carbon supercapacitors operating down to -40°C in
           aqueous electrolyte made with cholinium salt
    • Authors: Qamar Abbas; François Béguin
      Abstract: Cholinium chloride at a concentration of 5 mol kg-1 in water is proposed as low cost and environmentally friendly aqueous electrolyte enabling to extend the operating range of carbon/carbon supercapacitors (SCs) down to -40°C. This solution exhibits a pH close to neutrality (pH = 6.1) and high conductivity of 88 mS cm-1 at 24°C. The supercapacitors demonstrate a high capacitance of 126 F g-1 (per mass of one electrode) and long life span at voltages up to 1.5 V. At -40°C, the carbon/carbon SCs display excellent electrochemical characteristics featured by slightly reduced capacitance of 106 F g-1 and negligible ohmic losses. As compared to previous works, where anti-freezing additives were introduced in traditional neutral electrolytes, the low solubility of the salt and related poor conductivity of the solution is no longer an issue, which makes the cholinium salt aqueous solutions very promising for SCs operating at sub-ambient temperature conditions.
      PubDate: 2017-12-14T13:10:37.27311-05:0
      DOI: 10.1002/cssc.201701957
       
  • Achieving efficient electrocatalytic hydrogen evolution activity based on
           ultrafine and highly-dispersed RuPx encapsulated in N, P co-doped hollow
           carbon nanospheres
    • Authors: Jing-Qi Chi; Wen-Kun Gao, Jia-Hui Lin, Bin Dong, Kai-Li Yan, Jun-Feng Qin, Bin Liu, Yong-Ming Chai, Chen-Guang Liu
      Abstract: The ultrafine RuPx nanoparticles (NPs) encapsulated in uniform N, P co-doped hollow carbon nanospheres (RuPx@NPC) have been synthesized through a facile route of using aniline-pyrrole polymer nanospheres to disperse Ru ions with followed gas phosphorization process. The as-prepared RuPx@NPC exhibits uniform core-shell hollow nanospherical structures with ultrafine RuPx NPs as core and N, P co-doped carbon (NPC) as shell. So this strategy integrates many advantages of designing hollow nanostructures, providing conductive substrate and doping non-metal element. The obtained ultrathin NPC shell at high temperature can not only protect the high active phase of RuPx NPs from aggregation and corrosion in the electrolyte but also make the variation in the electronic structures and greatly improve charge transfer rate by N, P co-doping. The optimized RuPx@NPC sample at 900 °C exhibits Pt-like HER performance and long-time durability in acidic, alkaline and neutral solution. It requires a small overpotential of only 51 mV, 74 mV and 110 mV at 10 mA cm-2 in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS, respectively. So this work provides a new way to design unique phosphide-doped carbon heterostructures through inorganic-organic hybrid method as excellent HER electrocatalysts.
      PubDate: 2017-12-14T10:11:32.315676-05:
      DOI: 10.1002/cssc.201702010
       
  • Cyclopentanone derivatives from 5-hydroxymethylfurfural via
           1-hydroxyhexane-2,5-dione as intermediate
    • Authors: Bartosz Wozniak; Anke Spannenberg, Yuehui Li, Sandra Hinze, Johannes Gerardus de Vries
      Abstract: An efficient strategy for the conversion of biomass derived 5-hydroxymethyl-furfural (HMF) to 2-hydroxy-3-methylcyclopent-2-enone (MCP) via intramolecular aldol condensation of 1-hydroxyhexane-2,5-dione (HHD) has been developed. Further transformations of MCP towards the diol, enol acetate, levulinic acid and N-heterocyclic compounds are also reported.
      PubDate: 2017-12-13T06:07:53.752046-05:
      DOI: 10.1002/cssc.201702100
       
  • MnCo2O4/MoO2 Nanosheets Grown on Ni foam as Carbon- and Binder-free
           Cathode for Lithium-Oxygen Batteries with Long Life and High Efficiency
    • Authors: Xuecheng Cao; Zhihui Sun, Xiangjun Zheng, Chao Jin, Jinghua Tian, Xiaowei Li, Ruizhi Yang
      Abstract: Carbon is usually used as cathode material for Li-O2 batteries. However, the discharge product, such as Li2O2 and LiO2, could react with carbon to form insulating lithium carbonate layer, resulting in cathode passivation and capacity fading. To solve this problem, the development of non-carbon cathode is highly demanded. Herein, we have successfully synthesized MnCo2O4 (MCO) nanoparticles anchored on porous MoO2 nanosheets that are grown on Ni foam (current collector) (MCO/MoO2@Ni), acting as a carbon- and binder-free cathode for Li-O2 batteries, in an attempt to improve the electrical conductivity, electrocatalytic activity and durability. This MCO/MoO2@Ni electrode delivers excellent cyclability (more than 400 cycles) and rate performance (voltage gap of 0.75 V at 5000 mA g-1). Notably, the battery with this electrode exhibits a high energy efficiency (higher than 85 %). The advanced electrochemical performance of MCO/MoO2@Ni can be attributed to its high electrical conductivity, excellent stability and super electrocatalytic activity. This work offers a new strategy to fabricate high-performance Li-O2 batteries with non-carbon cathode materials.
      PubDate: 2017-12-13T05:12:32.666086-05:
      DOI: 10.1002/cssc.201702240
       
  • Complete Depolymerization and Repolymerization of a Sugar Poly(orthoester)
    • Authors: Lingyao Li; Sampa Maiti, Nicole A. Thompson, Ian J. Milligan, Wenjun Du
      Abstract: Invited for this month′s cover is the group of Wenjun Du at Central Michigan University. The cover picture shows a glycopolymer is undergoing a cycle of depolymerization and repolymerization. The Communication itself is available at 10.1002/cssc.201701870.“A polymer can “reincarnate”….” 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.201701870. View the Front Cover here: 10.1002/cssc.201702306.
      PubDate: 2017-12-13T03:40:37.27827-05:0
      DOI: 10.1002/cssc.201702307
       
  • Anionic Redox Chemistry in Polysulfide Electrode Materials for
           Rechargeable Batteries
    • Authors: Ekaterina D. Grayfer; Egor M. Pazhetnov, Mariia N. Kozlova, Sofya B. Artemkina, Vladimir E. Fedorov
      Abstract: The Cover Feature shows a representation of a future electric vehicle powered by Li-ion batteries with transition-metal polysulfide electrodes driven on a road. Polysulfide electrodes have an unusual operation mechanism featuring anionic redox processes in disulfide groups (S−S)2−. The main redox reaction is schematically drawn on the hand wheel. As an example, a fragment of the VS4 structure is displayed on the control panel. The yellow balls are S atoms connected in pairs and the blue balls are V atoms. The mountains at the backdrop are “filled” with fragments of TaS3 and NbS3 microstructures symbolizing the vast opportunities that the rich polysulfide family offers for energy conversion and storage. More information can be found in the Concept by Grayfer et al.
      PubDate: 2017-12-13T03:40:00.79167-05:0
      DOI: 10.1002/cssc.201702310
       
  • Multiple-Trapping Model for the Charge Recombination Dynamics in
           Mesoporous-Structured Perovskite Solar Cells
    • Authors: Hao-Yi Wang; Yi Wang, Ming-Yang Hao, Yujun Qin, Li-Min Fu, Zhi-Xin Guo, Xi-Cheng Ai, Jian-Ping Zhang
      Abstract: The Cover Feature shows a new physical model proposed to describe the biphasic charge-recombination process observed in mesoporous-structured perovskite solar cells. The perovskite phase and the mesoporous TiO2 phase dominate the charge-recombination process according to various trap-states distributions, and at different photovoltages, respectively. More information can be found in the Full Paper by Wang, Wang, et al.
      PubDate: 2017-12-13T03:39:47.859687-05:
      DOI: 10.1002/cssc.201702309
       
  • Reconsidering Water Electrolysis: Producing Hydrogen at Cathodes Together
           with Selective Oxidation of n-Butylamine at Anodes
    • Authors: Song Xue; Sebastian Watzele, Viktor Čolić, Kurt Brandl, Batyr Garlyyev, Aliaksandr S. Bandarenka
      Abstract: The Cover Feature shows a new approach for water electrolysis, by rethinking the reaction at the anode: n-butyronitrile from n-butylamine is selectively produced as an easily retrievable valuable product, instead of oxygen gas. We study industrially relevant oxygen evolution reaction catalysts, CoOx, NiFeOx, and NiOx. They all show lower anodic potentials in the presence of n-butylamonium sulfate, without poisoning the active sites of Pt electrocatalyst for the hydrogen evolution electrode side. The highest activities were observed for NiOx thin-film electrodes. More information can be found in the Communication by Xue, Watzele, et al.
      PubDate: 2017-12-13T03:38:34.341004-05:
      DOI: 10.1002/cssc.201702308
       
  • Complete Depolymerization and Repolymerization of a Sugar Poly(orthoester)
    • Authors: Lingyao Li; Sampa Maiti, Nicole A. Thompson, Ian J. Milligan, Wenjun Du
      Abstract: The Front Cover shows that a glycopolymer undergoing a cycle of depolymerization and repolymerization. In their Communication, the authors reversibly depolymerized a sugar poly(orthoester) under acidic conditions, demonstrating that regeneration of the monomer is possible. More information can be found in the Communication by Li et al.
      PubDate: 2017-12-13T03:38:32.223208-05:
      DOI: 10.1002/cssc.201702306
       
  • Magnetic Field Enhanced 4-electron Pathway by the Well-aligned Co3O4/ECNFs
           Design in the Oxygen Reduction Reaction
    • Authors: Zheng Zeng; Tian Zhang, Yiyang Liu, Wendi Zhang, Ziyu Yin, Zuowei Ji, Jianjun Wei
      Abstract: The sluggish reaction kinetics of oxygen reduction reaction (ORR) has been the limiting factor for fuel energy utilization, hence it is desirable to develop a high performance electrocatalysis with a 4-electron pathway ORR. Here, we report a constant low-current (50 μA) electrodeposition technique to develop a uniform Co3O4 film formation at the well-aligned electrospun carbon nanofibers (ECNFs) with a time-dependent growth mechanism. This work also reports a new finding of milli-Tesla (mT) magnetic field induced enhancement of electron exchange number of the ORR at glassy carbon electrode modified with the Co3O4/ECNFs catalyst. The magnetic susceptibility of the unpaired electrons in Co3O4 improves the kinetics and efficiency of electron transfer reactions in ORR, which shows a 3.92-electron pathway in the presence of a 1.32 mT magnetic field. This research presents a potential revolution of traditional electrocatalysts by simply applying an external magnetic field on metal oxides as replacement of noble metals to reduce the risk of the fuel cell degradation and maximize its energy output.
      PubDate: 2017-12-12T13:35:59.383699-05:
      DOI: 10.1002/cssc.201701947
       
  • Electrodeposition of Nickel Composite Nanoparticles for Alkaline Hydrogen
           Evolution Reaction: Correlating Electrocatalytic Behavior and Chemical
           Composition Obtained by XPS
    • Authors: Shasha Tao; Florent Yang, Jona Schuch, Wolfram Jaegermann, Bernhard Kaiser
      Abstract: Ni Nanoparticles (NPs) consisting of Ni, NiO and Ni(OH)2 have been formed on Ti substrates by electrodeposition as electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. The deposition parameters including the potential range and the scan rate were varied, and the resulting NPs were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. Additionally, the chemical composition of the NPs changes using different conditions, and it was found that the catalytic activity increases with an increasing amount of NiO. From these data optimized NPs have been synthesized; the best sample shows an onset potential of ~ 0 V and an overpotential (η) of 197 mV at a cathodic current density of 10 mA cm-2 as well as a small Tafel slope of 88 mV dec-1 in 1 M KOH, which are comparable values to a Pt-foil. These NPs consist of about 25% Ni and Ni(OH)2 each, as well as of about 50% of NiO. This implies, that in order to obtain a successful HER electrocatalyst, active sites with differing composition have to be close to each other to promote different reaction steps. Long-time measurements (30h) show an almost complete transformation of the highly active catalyst compound consisting of Ni0, NiO and Ni(OH)2 to the less active Ni(OH)2 phase. Nevertheless, the here employed electrodeposition of non-precious metal/metal oxide combination compounds represents a promising alternative to Pt-based electrocatalysts for the water reduction to hydrogen.
      PubDate: 2017-12-11T10:50:53.407098-05:
      DOI: 10.1002/cssc.201702138
       
  • Molecular Design of Efficient Organic D-A-π-A Dye Featuring
           Triphenylamine as Donor Fragment for Application in Dye-Sensitized Solar
           Cells
    • Authors: Anders Hagfeldt; Parnian Ferdowsi, Yasemin Saygili, Weiwei Zhang, Tomas Edvinsson, Ladislav Kavan, Javad Mokhtari, Shaik M. Zakeeruddin, Michael Grätzel
      Abstract: We designed, synthesized and characterized a novel metal-free organic sensitizer, suitable for the application in dye-sensitized solar cells (DSSCs), both experimentally and theoretically. The structure of the novel donor-acceptor-π-bridge-acceptor (D-A-π-A) dye has triphenylamine (TPA) segment and 4-(Benzo[c][1,2,5] thiadiazol-4-ylethynyl) benzoic acid (BTEBA). The triphenylamine unit is widely used as electron donor for the photosensitizers due to its outstanding characteristics, i.e. the non-planar molecular configuration and excellent electron donating capability while 4-(Benzo[c][1,2,5] thiadiazol-4-ylethynyl) benzoic acid is used as electron acceptor unit. We investigated the influence of iodide/triiodide, Cobalt(bpy)32+/3+ and Copper(tmby)22+/+complexes as redox electrolytes on the DSSC device performance. The maximal monochromatic incident photon to current conversion efficiency (IPCE) reached up to 81%. The solar light to electrical energy conversion efficiency of the devices with Cu(tmby)22+/+ reached up to 7.15%. The devices with Co(bpy)3 and Iodide/triiodide electrolytes showed 5.22% and 6.14% efficiency, respectively. The lowest device performance of Co(bpy)33+/2+ based electrolyte is attributed to the increased charge recombination process.
      PubDate: 2017-12-11T05:50:29.459735-05:
      DOI: 10.1002/cssc.201701949
       
  • Towards Sustainable H2 Production: Rational Design of Hydrophobic
           Triphenylamine-based Dyes for Sensitized Ethanol Photoreforming
    • Authors: Alessio Dessì; Matteo Monai, Matteo Bessi, Tiziano Montini, Massimo Calamante, Alessandro Mordini, Gianna Reginato, Cosimo Trono, Paolo Fornasiero, Lorenzo Zani
      Abstract: Donor-acceptor dyes are a well-established class of photosensitizers, used to enhance visible light harvesting in solar cells and in direct photocatalytic reactions, such as H2 production by photoreforming of sacrificial electron donors (SEDs). Amines - typically triethanolamine (TEOA) - are commonly employed as SEDs in such reactions. Dye-sensitized photoreforming of more sustainable, biomass-derived alcohols, on the other hand, was only recently reported using methanol as the electron donor. In this work, several rationally designed donor-acceptor dyes were used as sensitizers in H2 photocatalytic production, comparing the efficiency of TEOA and EtOH as SEDs. In particular, the effect of hydrophobic chains in the spacer and/or the donor unit of the dyes was systematically studied. The H2 production rates were higher when TEOA was used as SED, while the activity trends were dependent on the SED used. With TEOA, the best performance was obtained using a sensitizer (AD418) endowed with just one bulky hydrophobic moiety, propylenedioxythiophene (ProDOT), placed on the spacer unit. In the case of EtOH, the best performing sensitizers (TTZ4-5) were the ones featuring a thiazolo[5,4-d]thiazole internal unit, needed for enhancing light harvesting, and carrying alkyl chains on both the donor part and the spacer unit. The results are discussed in terms of reaction mechanism, interaction with SED and structural/ electrochemical properties of the sensitizers.
      PubDate: 2017-12-11T05:26:55.807821-05:
      DOI: 10.1002/cssc.201701707
       
  • Revealing the Chemistry between Bandgap and Binding Energy for Pb/Sn-based
           Trihalide Perovskite Solar Cell Semiconductors
    • Authors: Arpita Varadwaj; Pradeep R. Varadwaj, Koichi Yamashita
      Abstract: A relationship between reported experimental bandgaps (solid) and presently DFT-calculated binding energies (gas) is established for the first time for each of the four ten-membered lead (or tin) trihalide perovskite solar cell semiconductor series examined in this study, including CH3NH3PbY3, CsPbY3, CH3NH3SnY3 and CsSnY3, where Y = I(3 - x)Brx=1-3, I(3 - x)Clx=1-3, Br(3-x)Cl x=1-3, and IBrCl. The relationship unequivocally provides a new dimension for the fundamental understanding of the optoelectronic features of the solid state solar cell thin films using the 0 K gas-phase energetics of their corresponding molecular building blocks.
      PubDate: 2017-12-08T04:26:37.737226-05:
      DOI: 10.1002/cssc.201701653
       
  • Tracking Ionic Rearrangements and Interpreting Dynamic Volumetric Changes
           in Two-Dimensional Metal Carbides Supercapacitors: A Molecular Dynamics
           Simulation Study
    • Authors: Kui Xu; Zifeng Lin, Céline Merlet, Pierre-Louis Taberna, Ling Miao, Jianjun Jiang, Patrice Simon
      Abstract: We present a molecular dynamics simulation study achieved on two-dimensional (2D) Ti3C2Tx MXenes in an [EMIM]+[TFSI]- ionic liquid electrolyte. Our simulations reproduce the different patterns of volumetric change observed experimentally for both the negative and positive electrodes. The analysis of ionic fluxes and structure rearrangements in the 2D material provide an atomic scale insight into the charge and discharge processes in the layer pore and confirm the existence of two different charge storage mechanisms at the negative and positive electrodes. The ionic number variation and the structure rearrangement contribute to the dynamic volumetric changes of both electrodes: negative electrode expansion and positive electrode shrinkage.
      PubDate: 2017-12-06T12:36:39.075042-05:
      DOI: 10.1002/cssc.201702068
       
  • Efficient Yttrium(III) Chloride-Treated TiO2 Electron Transfer Layers for
           Performance-Improved and Hysteresis-Less Perovskite Solar Cells
    • Authors: Minghua Li; Yahuan Huan, Xiaoqin Yan, Zhuo Kang, Yan Guo, Yong Li, Xinqin Liao, Ruxiao Zhang, Yue Zhang
      Abstract: Hybrid organic–inorganic metal halide perovskite solar cells have attracted widespread attention, owing to their high performance, and have undergone rapid development. In perovskite solar cells, the charge transfer layer plays an important role for separating and transferring photogenerated carriers. In this work, an efficient YCl3-treated TiO2 electron transfer layer (ETL) is used to fabricate perovskite solar cells with enhanced photovoltaic performance and less hysteresis. The YCl3-treated TiO2 layers bring about an upward shift of the conduction band minimum (ECBM), which results in a better energy level alignment for photogenerated electron transfer and extraction from the perovskite into the TiO2 layer. After optimization, perovskite solar cells based on the YCl3-treated TiO2 layers achieve a maximum power conversion efficiency of about 19.99 % (19.29 % at forward scan) and a steady-state power output of about 19.6 %. Steady-state and time-resolved photoluminescence measurements and impedance spectroscopy are carried out to investigate the charge transfer and recombination dynamics between the perovskite and the TiO2 electron transfer layer interface. The improved perovskite/TiO2 ETL interface with YCl3 treatment is found to separate and extract photogenerated charge rapidly and suppress recombination effectively, which leads to the improved performance.Delete hysteresis' Efficient and hysteresis-less perovskite solar cells are prepared by using YCl3-treated TiO2 electron transfer layers. The YCl3 treatment increases the film conductivity and raises the lower boundary of the TiO2 conduction band. The average device efficiency reaches approximately 18.82 %, owing to better energy level alignment and favorable charge transfer.
      PubDate: 2017-12-06T06:10:38.568957-05:
      DOI: 10.1002/cssc.201701911
       
  • Nitrogen-doped carbon supported Co catalysts: An effective none-noble
           metal catalyst for the upgrade of biofuels
    • Authors: Liang Jiang; Peng Zhou, Chanjuan Liao, Zehui Zhang, Shi wei Jin
      Abstract: A new method has been developed for the deoxygenation of vanillin to produce 2-methoxy-4-methylphenol (MMP) as a promising liquid fuel over a heterogeneous non-noble metal catalyst. The nitrogen-doped carbon supported Co nanoparticles (Co/N-C-600) exhibited high activity and stability for the deoxygenation of vanillin into MMP under mild conditions (150 oC, 10 bar H2). Nearly quantitative MMP yield was obtained in iso-propanol after 8 h at 150 oC and 10 bar H2 pressure. According to the distribution of products with time, the deoxygenation of vanillin into MMP mainly underwent the hydrogenation of vanillin into vanillyl alcohol and the subsequent hydrogenolysis of vanillyl alcohol into MMP, and the latter was the rate-determining step, which had a much higher active energy. Moreover, after being recycled several times, the loss of catalytic activity was negligible, which demonstrated that the Co/N-C-600 catalyst had the property of resistance to deactivation.
      PubDate: 2017-12-06T04:05:41.408453-05:
      DOI: 10.1002/cssc.201702078
       
  • Kinematic Modelling of Mechanocatalytic Depolymerization of
           α-Cellulose and Beechwood
    • Authors: Martin Kessler; Robert Woodward, Narumi Wong, Roberto Rinaldi
      Abstract: Mechanocatalytic depolymerization of lignocellulose presents a promising method for the solid-state transformation of acidified raw biomass into water-soluble products (WSP). However, the mechanisms underlining the utilization of mechanical forces in the depolymerization is poorly understood. Herein, we applied a kinematic model of the milling process to assess the energy dose transferred to cellulose in its mechanocatalytic depolymerization performed under varied conditions (rotational speed, milling time, ball size and substrate loading). The data set was compared against the apparent energy dose results generated from the kinematic model and revealed key features of the mechanocatalytic process. At low energy dose, a rapid rise in the WSP yield associated with the apparent energy dose was observed. However, at a higher energy dose obtained by extended milling duration or high milling speeds, the formation of a substrate cake layer on the mill vials appear to buffer the mechanical forces, preventing full cellulose conversion into WSP. By contrast, for beechwood, there exists a good linear dependence between the WSP yield and the energy dose provided to the substrate over the entire range of WSP yield. As the formation of a substrate cake in depolymerization of beechwood is less severe compared to that observed for the cellulose, the current results verify the hypothesis regarding the negative effect of a substrate layer formed on the mill vials upon the depolymerization.
      PubDate: 2017-12-05T06:31:50.454856-05:
      DOI: 10.1002/cssc.201702060
       
  • Approaches to electrolyte solvent selection for Poly-anthraquinone
           sulphide (PAQS) organic electrode material
    • Authors: Satyajit Phadke; Mingli Cao, meriem anouti
      Abstract: Organic materials such as polyanthraquinone sulphide (PAQS) are receiving increased attention as electrodes for energy storage systems due to their good environmental compatibility, high rate capability and large charge storage capacity. However, one of their limits is the solubility in organic solvents composing the electrolytes. In this study, solubility of PAQS has been tested in 17 different solvents using UV-vis spectroscopy. Results show that PAQS exhibits a very wide range of solubility according to the nature of solvent and the obtained trend agrees well with the predictions from Hansen solubility analysis. In the second part of this study, the transport properties of electrolytes and electrochemical characterisation of PAQS as electrode material in selected pure or mixture of solvents with 1M LiTFSI as salt have been made in half-cells by galvanostatic method. In a methylglutaronitrile (2MeGLN) based electrolyte which exhibits low solubility of PAQS it appears that the capacity fade is intricately linked to the large irreversibility of the second step of the redox process. While, standard cyclic carbonate solvents mixture (EC and PC), lead to rapid capacity fade in the initial 10-15 cycles due to their high solubilizing ability. Finally, it is shown that a pure linear alkylcarbonate (DMC) or binary mixture of ethers (DOL/DME) based electrolyte is much more compatible for enhanced capacity retention in PAQS with more than 120 mAh.g-1 for 1000 cycles at 4C.
      PubDate: 2017-12-04T22:00:39.337942-05:
      DOI: 10.1002/cssc.201701962
       
  • Ultrafine VS4 Nanoparticles Anchored on Graphene Sheets as a High-Rate and
           Stable electrode Material for Sodium Ion Batteries
    • Authors: Qiang Pang; Yingying Zhao, Yanhao Yu, Xiaofei Bian, Xudong Wang, Yingjin Wei, Yu Gao, Gang Chen
      Abstract: Size and conductivity of the electrode materials play a significant role in improving the kinetics of sodium ion batteries. Various characterizations demonstrate that size-controllable VS4 nanoparticles are successfully anchored on graphene sheets (GS) surfaces by a simple cationic surfactant-assisted hydrothermal method. When used as an electrode material for sodium ion batteries, these VS4/GS nanocomposites show large specific capacity (349.1 mA∙h∙g-1 after 100 cycles), excellent long-term stability (84% capacity retention after 1200 cycles), and high rate capability (188.1 mA∙h∙g-1 at 4000 mA∙g-1). A large proportion of the capacity is contributed by capacitive processes. This remarkable electrochemical performance is attributed to synergistic interactions between nanosized VS4 particles and a highly conductive graphene network that provided short diffusion pathways for Na+ ions and large contact areas between the electrolyte and electrode, resulting in much improved electrochemical kinetic properties.
      PubDate: 2017-12-04T10:00:24.130373-05:
      DOI: 10.1002/cssc.201702031
       
  • Rational Development of Neutral Aqueous Electrolytes for Zinc–Air
           Batteries
    • Authors: Simon Clark; Arnulf Latz, Birger Horstmann
      Abstract: The Cover Feature shows a schematic of a promising zinc–air battery with a water-based, pH-neutral electrolyte. Zinc–air batteries are safe, use common and non-toxic materials, and could achieve a significant increase in energy density over lithium-ion batteries. Successful development of this battery could have far-reaching implications for renewable energy storage and electric mobility. This study presents the first continuum simulation of zinc–air batteries in aqueous ZnCl2–NH4Cl, and derives a new framework for modeling pH-buffered electrolytes. More information can be found in the Full Paper by Clark et al.
      PubDate: 2017-12-04T08:26:32.562762-05:
      DOI: 10.1002/cssc.201702216
       
  • A Strategy for the Simultaneous Synthesis of Methallyl Alcohol and Diethyl
           Acetal with Sn-β
    • Authors: Wenda Hu; Yan Wan, Lili Zhu, Xiaojie Cheng, Shaolong Wan, Jingdong Lin, Yong Wang
      Abstract: Invited for this month′s cover is the group of Yong Wang at Xiamen University. The cover picture shows a strategy to simultaneously produce two important chemicals, namely, methallyl alcohol and diethyl acetal from methacrolein in ethanol solvent at low temperature on Beta zeolites modified by tin (Sn-β catalysts). The Full Paper itself is available at 10.1002/cssc.201701435.“The biggest challenge was to understand the complex reaction network and the reaction mechanism…” 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.201701435. View the Front Cover here: 10.1002/cssc.201702213.
      PubDate: 2017-12-04T08:26:25.182974-05:
      DOI: 10.1002/cssc.201702214
       
  • Electrocatalytic Alloys for CO2 Reduction
    • Authors: Jingfu He; Noah J. Johnson, Aoxue Huang, Curtis Berlinguette
      Abstract: Electrochemically reducing CO2 into fuels using renewable energy is a contemporary global challenge. Catalysts that can mediate the conversion with low overpotential and high selectivity is required. Pure metals have been studied for catalyzing these conversions for decades, but alloys have recently gained attention as a new parameter space for catalyst discovery. The appealing aspect of these systems is that the relative metal content can be tuned to alter the electronic and geometric structure around the active sites to potentially achieve higher product selectivities and efficiencies. We summarize the current status in the understanding of various mixed-metal/alloy compositions that have been evaluated for electrocatalytic CO2 reduction and attempt to distill structure-property relationships that can guide new catalyst discovery.
      PubDate: 2017-12-04T06:30:43.563961-05:
      DOI: 10.1002/cssc.201701825
       
  • Solid Aluminum Borohydrides for Prospective Hydrogen Storage
    • Authors: Iurii Dovgaliuk; Damir A. Safin, Nikolay A. Tumanov, Fabrice Morelle, Adel Moulai, Radovan Černý, Zbigniew Łodziana, Michel Devillers, Yaroslav Filinchuk
      Abstract: The Cover Feature shows novel aluminum-based metal borohydrides as high-capacity hydrogen storage materials. The conversion of hydrogen-rich but explosive liquid Al(BH4)3 to a more stable family of mixed-cation M[Al(BH4)4] (M=alkali metal or NH4+) solid borohydrides opens new doors for energy storage. Their thermal decomposition properties show diverse behaviors and provides this family of solids with convenient and versatile properties, putting aluminum borohydride chemistry in the mainstream of the hydrogen storage research. More information can be found in the Full Paper by Dovgaliuk et al.
      PubDate: 2017-12-04T04:11:03.473025-05:
      DOI: 10.1002/cssc.201702215
       
  • Insights into MOF Reactivity: Chemical Water Oxidation Catalysis
           [Ru(tpy)(dcbpy)OH2]2+ Modified Metal-Organic Framework
    • Authors: Shaoyang Lin; Alireza K Ravari, Jie Zhu, Pavel Usov, Meng Cai, Spencer R Ahrenholtz, Yulia Pushkar, Amanda Morris
      Abstract: Investigation of chemical water oxidation was conducted on the [Ru(tpy)(dcbpy)OH2]2+ (tpy = 2,2′:6′,2′′-terpyridine, dcbpy = 5,5′-dicarboxy-2,2′-bipyridine) -doped UiO-67 metal-organic framework (MOF). The MOF catalyst exhibited single site reaction pathway with similar kinetic behavior as the homogeneous Ru complex. The reaction was first order with respect to both the concentration of Ru catalyst and cerium ammonium nitrate (CAN), with kcat = 3 (±2) ×10-3 M-1s-1 in HNO3 (pH 0.5). The common degradation pathways of ligand dissociation and dimerization were precluded by MOF incorporation, leading to sustained catalysis and greater reusability as opposed to the molecular catalyst in homogeneous solution. Lastly, at the same loading (~97 nmol/mg), samples of different particle size generated the same amount of oxygen (~100 nmol) indicative of in-MOF reactivity. The results suggest that the rate of redox hopping charge transport is sufficient to promote chemistry throughout the MOF particulates.
      PubDate: 2017-12-02T00:35:31.624184-05:
      DOI: 10.1002/cssc.201701644
       
  • Coffee waste templating of metal ion substituted cobalt oxides for oxygen
           evolution reaction
    • Authors: Mingquan Yu; Candace Chan, Harun Tüysüz
      Abstract: A facile and scalable method using coffee waste grounds as hard template was developed to fabricate nanostructured Co3O4 for the oxygen evolution reaction (OER). Co3O4 incorporated with different valent metals (M = Cu, Ni, Fe, Cr and W, M/Co: 1/4) were also prepared with similar sheet-like structure comprising nanosized crystallites. After a detailed characterization using X-ray diffraction, electron microscopy and nitrogen sorption, the oxides were employed as OER electrocatalysts. Substitution of octahedral and tetrahedral sites of the spinel structure with divalent and trivalent transition metals (Cu, Ni, Fe and Cr) increases the activity of Co3O4 for OER, while the incorporation of hexavalent W leads to a second crystal phase and significantly higher electrocatalytic performance. Furthermore, this method is easily scaled up for mass production of Co3O4 with the same nanostructure, which is highly desirable for large-scale application.
      PubDate: 2017-12-01T11:35:24.970195-05:
      DOI: 10.1002/cssc.201701877
       
  • Selective electrogenerative oxidation of 5-hydroxymethylfurfural to
           2,5-furandialdehyde
    • Authors: Tao Cao; Mengjia Wu, Vitaly V. Ordomsky, Xi Xin, Hao Wang, Pascal Metivier, Marc Pera-Titus
      Abstract: 2,5-furandialdehyde (DFF) was synthesized by electrogenerative oxidation of 5-hydroxymethylfurfural (HMF) over a PtRu catalyst with 89% selectivity at 50 oC after 17 h. This approach opens an avenue for a selective, energy-efficient and green oxidation of biomass-derived platform alcohols to added-value chemicals.
      PubDate: 2017-12-01T07:35:26.064154-05:
      DOI: 10.1002/cssc.201702119
       
  • Selective hydrogenolysis of furfural-derivative 2-methyltetrahydrofuran
           into pentanediol acetate and pentanol acetate over Pd/C and Sc(OTf)3
           co-catalytic system
    • Authors: Kun Zhang; Xing-Long Li, Shi-Yan Chen, Hua-Jian Xu, Jin Deng, Yao Fu
      Abstract: It is of great significance to convert platform molecules and their derivatives into high value-added alcohols which had multitudinous applications. We systematically studied the conversion of 2-methyl tetrahydrofuran (MTHF), which obtained from furfural, to 1-pentanol acetate (PA) and 1,4-pentandiol acetate (PDA) in this paper. The reaction parameters such as the species of Lewis acid, reaction temperature, hydrogen pressure, etc. were investigated and discussed in detail. 1H-NMR analysis and reaction dynamics were also conducted to help clarify the reaction mechanism. Results suggested that the cleavage of primary alcohol acetate was harder to occur than that of secondary alcohol acetate with the main product being PA. A yield of 91.8% PA (150 C, 3 MPa H2, for 30 min) was achieved by using Pd/C + Sc(OTf)3 co-catalytic system and 82% yield of PDA was achieved (150 C, for 30 min) by using Sc(OTf)3 catalyst, respectively. Simultaneously, the efficient conversion of acetic esters to alcohols by simple saponification were carried out and obtained a good yield.
      PubDate: 2017-12-01T01:35:50.840553-05:
      DOI: 10.1002/cssc.201702073
       
  • Computational screening of doped αMnO2 catalysts for the oxygen
           evolution reaction
    • Authors: Vladimir Tripkovic; Heine Anton Hansen, Tejs Vegge
      Abstract: Minimizing energy and materials costs for driving the oxygen evolution reaction (OER) is paramount for the commercialization of water electrolysis cells and rechargeable metal-air batteries. Using density functional theory calculations, we analyze the structural stability, catalytic activity and electronic conductivity of pure and doped αMnO2 for the OER. As a model surface, we investigate the (110) and (100) facets, on which we identify three possible active sites: a coordination unsaturated, bridge and bulk site. We evaluate the performance of pure and Cr, Fe, Co, Ni, Cu, Zn, Cd, Mg, Al, Ga, In, Sc, Ru, Rh, Ir, Pd, Pt, Ti, Zr, Nb and Sn doped αMnO2. At each site and for each dopant, we impose the preferred valence by adding/subtracting electron donors (hydrogens) and electron acceptors (hydroxyls). From a subset of stable dopants, we identify Pd doped αMnO2 as the only catalyst that can outperform pristine aMnO2. We also discuss approaches to increase the electron conductivity as pure αMnO2 is a narrow band-gap material.
      PubDate: 2017-11-30T06:00:50.66025-05:0
      DOI: 10.1002/cssc.201701659
       
  • Nonstoichiometric CuxInyS Quantum Dots for Efficient Photocatalytic
           Hydrogen Evolution
    • Authors: Xiang-Bing Fan; Shan Yu, Fei Zhan, Zhi-Jun Li, Yu-Ji Gao, Xu-Bing Li, Li-Ping Zhang, Ye Tao, Chen-Ho Tung, Li-Zhu Wu
      Abstract: Unlike their bulk counterpart, CuxInyS quantum dots (QDs) prepared by an aqueous synthetic approach, show promising activity for photocatalytic hydrogen evolution, which is competitive with the state-of-the-art Cd chalcogen QDs. Moreover, the as-prepared CuxInyS QDs with In-rich composition show much better efficiency than the stoichiometric ones (Cu/In=1:1).Indium summer: CuxInyS quantum dots (QDs) prepared by an aqueous synthetic approach are demonstrated to be promising candidates for photocatalytic H2 evolution. The In-rich CuxInyS QDs show much better activity than stoichiometric CuInS2 QDs (Cu/In=1:1) and are comparable to the state-of-the-art Cd chalcogen (CdS, CdSe, and CdTe) QDs for H2 generation under visible-light irradiation.
      PubDate: 2017-11-30T05:45:57.514613-05:
      DOI: 10.1002/cssc.201701950
       
  • Bismuth vanadate photoelectrodes with high photovoltage behave as
           photoanode and photocathode in photoelectrochemical cells for water
           splitting
    • Authors: Wayler S. dos Santos; Mariandry Rodriguez, Júlia M. O. Khoury, Luíza A. Nascimento, Rebecca J. P. Ribeiro, João P. Mesquita, Adilson C. Silva, Francisco G. E. Nogueira, Marcio Cesar Pereira
      Abstract: Using dual-photoelectrode photoelectrochemical (PEC) devices based on earth-abundant metal oxides for the unbiased water splitting is an attractive way for producing the green H2 fuel, but challenging due to low photovoltages generated by PEC cells. Here we demonstrate that this problem can be solved by coupling the n-type BiVO4 with n-type Bi4V2O11 to create a virtual p/n junction due to the formation of a hole inversion layer at the semiconductor interface. Thus, photoelectrodes with high photovoltage outputs were synthesized. The photoelectrodes exhibited features of p- and n-type semiconductors when illuminated under an applied bias, suggesting their use as photoanode and photocathode in a dual-photoelectrode PEC cell. This concept was proved by connecting the 1 mol% W-doped BiVO4/Bi4V2O11 photoanode with the undoped BiVO4/Bi4V2O11 photocathode, which produced a high photovoltage of 1.54 V, sufficient to drive the stand-alone water splitting with 0.95% efficiency.
      PubDate: 2017-11-29T14:30:36.347572-05:
      DOI: 10.1002/cssc.201701929
       
  • Interfacial Engineering of Supported Liquid Membranes by Vapor
           Cross-Linking for Enhanced Separation of Carbon Dioxide
    • Authors: Li-Yun Kong; Wei-Da Shan, Sheng-Li Han, Tao Zhang, Lang-Chong He, Kuan Huang, Sheng Dai
      Abstract: Supported liquid membranes (SLMs) based on ionic liquids (ILs) with not only high gas permeability and selectivity, but also high stability under high pressure, are highly desired for gas separation applications. In this work, permeable and selective polyamide network (PN) layers are deposited on the surface of SLMs by utilizing the cross-linking reaction of trimesoyl chloride, which was pre-dispersed in the SLMs, and vapor of amine linkers. The vapor cross-linking method makes it easy to control the growth and aggregation of PN layers, owing to the significantly reduced reaction rate, and thereby ensuring the good distribution of PN layers on the surface of SLMs. With rational choice of amine linkers and optimization of vapor cross-linking conditions, the prepared sandwich-like PN@SLMs with ILs embedded homogeneously within polymeric matrices displayed much-improved CO2 permeability and CO2/N2 selectivity in relation to the pristine SLMs. Moreover, those SLMs with ILs impregnated into porous supports physically displayed improved stability under high pressure after vapor cross-linking, because the PN layers formed on the surface of SLMs help prevent the ILs from being squeezed out. This interfacial engineering strategy represents a significant advance in the surface modification of SLMs to endow them with promising applications in CO2 capture.SLM dunk! A vapor cross-linking strategy was developed for the surface modification of supported liquid membranes (SLMs) based on ionic liquids. Permeable and selective polyamide network layers were deposited on the surface of SLMs. The prepared composite membranes showed significantly improved performance for the selective separation of CO2 from N2, or enhanced stability against transmembrane pressure difference, in relative to pristine SLMs.
      PubDate: 2017-11-29T08:01:34.924403-05:
      DOI: 10.1002/cssc.201701851
       
  • Cascade production of lactic acid from universal types of sugars catalyzed
           by lanthanum triflate
    • Authors: Dajiang Liu; Kwang Ho Kim, Jian Sun, Blake Simmons, Seema Singh
      Abstract: Lignocellulosic biomass conversion to value-added platform chemicals in the non-toxic, water-tolerant Lewis acid, and water solutions bears the hallmark of green chemistry. Lactic acid derived from biomass is an important chemical building block for biodegradable polymers such as polylactide. Herein, a universal method of converting lignocellulosic sugars to lactic acid using catalytic amount of water-stable Lewis acid La(OTf)3 is demonstrated. The lignocellulosic sugars studied in this work include 1) pyrolytic sugars from pyrolysis oil, and 2) sugars derived from ionic liquid (IL)-pretreated biomass. Under moderate conditions (250 °C, 1 h), levoglucosan (major pyrolytic sugar), glucose and xylose were converted to lactic acid with the carbon-based molar yields of 75%, 74% and 61% respectively. Furthermore, ~49 mol% (based on levoglucosan) and ~74 wt% (relative to pretreated biomass) of lactic acid were obtained from the conversion of pyrolytic sugars and sugar rich fraction after lignin removal from switchgrass, respectively. To the best of our knowledge, this is the first time to convert pyrolytic sugar into lactic acid by chemocatalysis and also lignocellulosic sugars are converted to lactic acid without hydrolysis. This approach could potentially be extended to other lignocellulosic sugars after simple removal of lignin from biomass pretreatment, rendering moderate to high yields of lactic acid.
      PubDate: 2017-11-27T00:52:55.971191-05:
      DOI: 10.1002/cssc.201701902
       
  • High loading solubilization and upgrading of poly(ethylene terephthalate)
           in low cost bifunctional ionic liquid
    • Authors: Jian Sun; Dajiang Liu, Robert P. Young, Alejandro G. Cruz, Nancy G. Isern, Timo Schuerg, John R. Cort, Blake A. Simmons, Seema Singh
      Abstract: High loading solubilization and efficient upgrading polyethylene terephthalate (PET) is of significant importance but challenging and most solvents for PET are highly toxic. In this work, we demonstrate for the first time that a low cost (~$1.2/kg) and biocompatible ionic liquid (IL), cholinium phosphate ([Ch]3[PO4]) can play bifunctional roles in PET solubilization and glycolytic degradation. High loading of PET (10 wt%) is readily dissolved in [Ch]3[PO4] at relatively low temperatures (120 °C, 3h) and even in water-rich conditions. In depth analysis of PET-IL solution reveals that the high PET solubilization in [Ch]3[PO4] can be ascribed to significant PET depolymerization. Acid precipitation yields terephthalic acid as the dominant depolymerized monomer with a theoretical yield of ~95%. Further exploration shows that in the presence of ethylene glycol, [Ch]3[PO4] catalyzed glycolysis of PET can efficiently occur with ~100% PET conversion and ~60.6% bis(2-hydroxyethyl)terephthalate (BHET) yield under metal free conditions. The IL can be reused at least three times without an apparent decrease in activity. NMR analysis reveals that strong hydrogen bond interactions between EG and the IL play an important role for EG activation and promotion of the glycolysis reaction. This study opens up avenues for exploring environmentally benign and efficient technology of ILs for solubilizing and recycling postconsumer polyester plastics.
      PubDate: 2017-11-27T00:51:15.958892-05:
      DOI: 10.1002/cssc.201701798
       
  • Complementary strategies towards the aqueous processing of high-voltage
           LiNi0.5Mn1.5O4 lithium-ion cathodes: Crosslinking CMC and phosphoric acid
           treatment
    • Authors: Matthias Kuenzel; Dominic Bresser, Thomas Diemant, Diogo Viera Carvalho, Guk-Tae Kim, Juergen Behm, Stefano Passerini
      Abstract: Increasing the environmental benignity of lithium-ion batteries is one of the greatest challenges for their large-scale deployment. Toward this end, we present herein a strategy to enable the aqueous processing of high-voltage LiNi0.5Mn1.5O4 (LNMO) cathodes, which are considered highly, if not the most, promising for the realization of cobalt-free next generation lithium-ion cathodes. Combining the addition of phosphoric acid with the crosslinking of sodium carboxymethyl cellulose by means of citric acid, aqueously processed electrodes with excellent performance are produced. The combined approach offers synergistic benefits, resulting in stable cycling performance and excellent coulombic efficiency (98.96%) in lithium metal cells. Remarkably, this approach can be easily incorporated into standard electrode preparation processes with no additional processing step.
      PubDate: 2017-11-24T09:56:34.268732-05:
      DOI: 10.1002/cssc.201702021
       
  • Capacitance Assisted Sustainable Electrochemical Carbon Dioxide
           Mineralisation
    • Authors: Katie Lamb; Mark Dowsett, Konstantinos Chatzipanagis, zhan Scullion, roland kroger, james lee, pedro aguiar, Michael North, alison parkin
      Abstract: An electrochemical cell comprising a novel dual-component graphite and Earth-crust abundant metal anode, a hydrogen producing cathode and an aqueous sodium chloride electrolyte has been constructed and used for carbon dioxide mineralisation. Under an atmosphere of 5% carbon dioxide in nitrogen, the cell exhibited both capacitive and oxidative electrochemistry at the anode. The graphite acted as a supercapacitive reagent concentrator, pumping carbon dioxide into aqueous solution as hydrogen carbonate. Simultaneous oxidation of the anodic metal generated cations which reacted with the hydrogen carbonate to give mineralised carbon dioxide. Whilst conventional electrochemical carbon dioxide reduction requires hydrogen, this cell generates hydrogen at the cathode. Carbon capture can be achieved in a highly sustainable manner using scrap metal within the anode, seawater as the electrolyte, an industrially-relevant gas stream and a solar panel as an effectively zero-carbon energy source.
      PubDate: 2017-11-24T06:25:31.893841-05:
      DOI: 10.1002/cssc.201702087
       
  • Micelle-assisted electrodeposition of mesoporous Fe-Pt smooth thin films
           onto various substrates and their electrocatalytic activity towards
           hydrogen evolution reaction
    • Authors: Eloy Isarain-Chávez; Maria Dolors Baró, Carlos Alcantara, Salvador Pané, Jordi Sort, Eva Pellicer
      Abstract: Mesoporous Fe-Pt thin films are obtained by micelle-assisted electrodeposition onto metallic substrates with dissimilar activity (namely, gold, copper, and aluminum seed-layers evaporated on Si/Ti) under constant applied potential (E= -1.1 V vs. Ag/AgCl) and deposition time (600 s). The amphiphilic triblock copolymer Pluronic P-123 is used as a soft-template to guide the formation of mesopores. The occurrence of pores (ca. 7 nm in diameter) with narrow size distribution, regularly distributed over the surface, is observed in all cases. Despite the applied conditions being the same, the roughness and the amount of Fe incorporated in the films are influenced by the substrate nature. In particular, ultra-smooth films containing a larger amount of Fe (21 wt.%) are achieved when deposition takes place on the Au surface. X-ray diffraction analyses reveal that Pt and Fe are alloyed to a certain extent, although some iron oxides/hydroxides also unavoidably form. The resulting films have been tested as electocatalysts in the hydrogen evolution reaction (HER) in alkaline media. The mesoporous Fe-rich Fe-Pt films on Au show excellent HER activity and cyclability.
      PubDate: 2017-11-22T10:20:29.903074-05:
      DOI: 10.1002/cssc.201701938
       
  • Impact of Flue Gas Compounds on Microalgae and Mechanisms for Carbon
           Assimilation and Utilization - A Review
    • Authors: Arun Krishna Vuppaladadiyam; Joseph G Yao, Nicholas Florin, Anthe George, Xiaoxiong Wang, Leen Labeeuw, Yuelu Jiang, Ryan W. Davis, Ali Abbas, Peter Ralph, Paul S. Fennell, Ming Zhao
      Abstract: In order to shift the world to a more sustainable future, it is necessary to phase out the use of fossil fuels and focus on the development of low-carbon alternatives. However, this transition is slow so there still exists a large dependence on fossil-derived power and therefore CO2 release. Owing to the potential for assimilating and utilizing CO2 to generate carbon neutral products such as biodiesel, the application of microalgae technology to capture CO2 from flue gases has gained significant attention over the past decade. Microalgae offer a more sustainable source of biomass energy over conventional fuel crops since they grow more quickly and do not adversely affect food supply. This review focuses on the technical feasibility of combined carbon fixation and microalgae cultivation for carbon reuse. We appraise a range of different C metabolisms and the impact of flue gas compounds on microalgae. Fixation of flue gas CO2 is found to be dependent on the selected microalgae strain and on flue gas compounds/concentrations. Additionally, we assess current pilot-scale demonstrations of microalgae technology for CO2 capture as well as discuss its future prospects. Practical implementation of this technology at an industrial-scale still requires significant research, necessitating multidiscipline R&D to demonstrate its viability for CO2 capture from flue gases at the commercial level.
      PubDate: 2017-11-22T06:50:22.991437-05:
      DOI: 10.1002/cssc.201701611
       
  • Anionic Redox Chemistry in Polysulfide Electrode Materials for
           Rechargeable Batteries
    • Authors: Ekaterina D. Grayfer; Egor M. Pazhetnov, Mariia N. Kozlova, Sofya B. Artemkina, Vladimir E. Fedorov
      Abstract: Classical Li-ion battery technology is based on the insertion of lithium ions into cathode materials involving metal (cationic) redox reactions. However, this vision is now being reconsidered, as many new-generation electrode materials with enhanced reversible capacities operate through combined cationic and anionic (non-metal) reversible redox processes or even exclusively through anionic redox transformations. Anionic participation in the redox reactions is observed in materials with more pronounced covalency, which is less typical for oxides, but quite common for phosphides or chalcogenides. In this Concept, we would like to draw the reader's attention to this new idea, especially, as it applies to transition-metal polychalcogenides, such as FeS2, VS4, TiS3, NbS3, TiS4, MoS3, etc., in which the key role is played by the (S−S)2−/2 S2− redox reaction. The exploration and better understanding of the anion-driven chemistry is important for designing advanced materials for battery and other energy-related applications.An-ion of interest: Conventional Li-ion batteries operate through Li insertion/metal redox reactions. However, there is growing evidence that this mechanism is not the only one. Here, we emphasize the role of anion redox reactions in new-generation electrode materials, especially, in transition-metal polysulfides such as trichalcogenides, VS4, FeS2, etc., in which the key role is played by the S2-2/S2− transformation.
      PubDate: 2017-11-22T03:56:27.636739-05:
      DOI: 10.1002/cssc.201701709
       
  • Continuous flow synthesis of supported magnetic iron oxide nanoparticles
           for efficient isoeugenol conversion to vanillin
    • Authors: María Dolores Marquez; Pepijn Prinsen, Hangkong Li, Kaimin Shih, Antiono Ángel Romero Reyes, Rafael Luque
      Abstract: This work presents the synthesis of iron oxide nanocatalysts supported on mesoporous Al-SBA-15 using a continuous flow set-up. The magnetic solid nanoparticles were tested as catalysts for the oxidative disruption of isoeugenol using hydrogen peroxide as the oxidant, showing all high activity (63-88 % conversion) and fare selectivity to vanillin (44-68 %). The nanoparticles exhibited good magnetic properties, whensynthesized at continuous flow temperatures not exceeding 190 °C, which is important to enable their efficient separation from reaction mixtures. The use of microwave irradiation reduced the reaction times drastically, but had negative effects on the catalyst re-usability.
      PubDate: 2017-11-21T15:20:22.463654-05:
      DOI: 10.1002/cssc.201701884
       
  • Bioinspired Mesoporous Chiral Nematic Graphitic Carbon Nitride for
           Ultrahigh Photocatalytic Activity with Polarized Light Modulations
    • Authors: Wensheng Lin; Wei Hong, Lu Sun, Di Yu, Dingshan Yu, Xudong Chen
      Abstract: Endowing materials with chirality and exploring the responses of the material under circularly polarized light (CPL) can gain further insight into the physical and chemical properties of the semiconductors, thus expand the optoelectronic applications. Herein we report a bioinspired mesoporous chiral nematic graphitic carbon nitride (g-C3N4) for efficient hydrogen evolutions with polarized light modulations based on chiral nematic cellulose nanocrystal films through silica templating. The mesoporous nematic chiral g-C3N4 exhibits an ultrahigh hydrogen evolution rate of 219.9 μmolh-1 and a high enhancement factor of 54.9 when compared to the bulk g-C3N4 under λ>420 nm irradiation. Furthermore, the chiral g-C3N4 exhibits unique photocatalytic activity modulated by CPL within the absorption region. This CPL-assisted photocatalytic regulation strategy holds great promises for a wide range of applications including optical devices, asymmetric photocatalysis and chiral recognition/separation.
      PubDate: 2017-11-21T11:20:34.433643-05:
      DOI: 10.1002/cssc.201701984
       
  • Highly Efficient Perovskite Solar Cells Based on Zn2Ti3O8 Nanoparticles as
           Electron Transporting Material with Efficiency over 17%
    • Authors: Zhong-Ning Chen; Aiying Pang, Deli Shen, Mingdeng Wei
      Abstract: Developing ternary metal oxides as electron transporting layers (ETL) for perovskite solar cell is highly challenging in the field of third-generation photovoltaics. In this study, highly mesoporous zinc titanate oxide (Zn2Ti3O8) scaffold synthesized by ion-exchange method has been successfully used as ETL for the fabrication of methyl ammonium lead halide (CH3NH3PbI3) perovskite solar cells. The optimized devices exhibit 17.21% power conversion efficiency (PCE) with open circuit voltage (Voc) of 1.02 V, short-circuit current density (Jsc) of 21.97 mA cm-2 and fill factor (FF) of 0.77 under AM 1.5 G sunlight (100 mW cm−2). The PCE is obviously higher than that based on mesoporous TiO2 (ST01) layer (η = 14.93%), which is ascribed to deeper conductive band of Zn2Ti3O8 nanoparticles, better light absorption and smaller charge recombination. The devices stored for 100 days at ambient temperature with humidity of 10% show excellence stability with only 12% reduction of the PCE. The charge transmission kinetic and long-term stability parameters of the ZTO-based perovskite film growth are discussed as well.
      PubDate: 2017-11-21T08:50:52.960249-05:
      DOI: 10.1002/cssc.201701779
       
  • Bio-derived muconates via cross-metathesis and their conversion to
           terephthalates
    • Authors: Erisa Saraci; Lan Wang, Klaus Theopold, Raul Francisco Lobo
      Abstract: Renewable terephthalic acid or its precursors can be obtained via Diels-Alder cycloaddition and further dehydrogenation of biomass-derived muconic acid. We have investigated the synthesis of dialkyl muconates via cross-metathesis. We show that Ru-catalyzed cross-coupling of sorbates with acrylates—which can be bio-sourced—proceeds selectively to yield up to 41% di-ester muconates using very low catalyst amounts (0.5 - 3.0 mol.%) and no solvent. In the optimized procedure, the muconate precipitates as a solid and is easily recovered from the reaction medium. GC-MS and NMR analysis showed that this method delivers exclusively the trans,trans isomer of dimethyl muconate. The Diels-Alder reaction of dimethyl muconate with ethylene was studied in various solvents to obtain the 1,4-bis(carbomethoxy) cyclohexene. The cycloaddition proceeded in very high conversion (77 - 100%) and yield (70 − 98%) in all solvents investigated, methanol and tetrahydrofuran being the best. Next, the aromatization of 1,4-bis(carbomethoxy) cyclohexene to dimethyl terephthalate over Pd/C catalyst resulted in up to 70% yield in tetrahydrofuran and an air atmosphere. Due to the high yield of the reaction of dimethyl muconate to 1,4-bis(carbomethoxy) cyclohexene, no separation step is needed before the aromatization. This is the first time that cross-metathesis has been used to produce bio-derived trans,trans-muconates as precursors to renewable terephthalates.
      PubDate: 2017-11-20T21:50:47.396858-05:
      DOI: 10.1002/cssc.201701874
       
  • Pyran-bridged indacenodithiophene: A novel building block for constructing
           efficient A-D-A type nonfullerene acceptor for polymer solar cells
    • Authors: Renqiang Yang; Shuguang Wen, Yao Wu, Yingying Wang, Yi Li, Ling Liu, Huanxiang Jiang, Zhitian Liu
      Abstract: In recent years, nonfullerene acceptors have attracted much attention due to their great potential for achieving high performance polymer solar cells. In this paper, a novel ladder type building block of pyran-bridged indacenodithiophene (PDT) has been designed for constructing A-D-A nonfullerene acceptors through introducing oxygen atoms into the commonly used indacenodithiophene (IDT) unit. The key step for the synthesis of PDT unit is accomplished by a BBr3-mediated tandem cyclization-deprotection reaction to construct the pyran-ring. In this approach, a novel molecular acceptor PTIC was successfully synthesized and applied in polymer solar cell device. Compared to the IDT-based acceptor, PTIC exhibits higher HOMO levels and wider optical bandgap at 550-800 nm. Polymer solar cells devices fabricated with PBDB-T:PTIC as active layer show a power conversion efficiency (PCE) of 7.66%. The introduction of oxygen atoms would be an effective approach for the modification of acceptor materials for polymer solar cells.
      PubDate: 2017-11-19T22:16:08.670735-05:
      DOI: 10.1002/cssc.201701917
       
  • Effect of Tetrahydrofuran on the Solubilisation and Depolymerisation of
           Cellulose in a Biphasic System
    • Authors: Changwei Hu; Zhicheng Jiang, Pingping Zhao, Jianmei Li, Xudong Liu
      Abstract: The dissolution of cellulose from biomass is a crucial but complicated issue for the utilisation of biomass resources, because of the extreme insolubility of cellulose. Herein, a biphasic NaCl-H2O-tetrahydrofuran system was studied, where most of the pure microcrystalline cellulose (M-cellulose, 96.6% conversion at 220 oC) and that contained in actual biomass were converted. Nearly a half of O(6)H***O(3) intermolecular hydrogen bonding could be broken by THF in H2O-THF co-solvent system, whereas the cleavage of O(2)H***O(6) intramolecular hydrogen bonding by H2O was significantly inhibited. In NaCl-H2O-THF system, THF could significantly promote the effects of both H2O and NaCl on the disruption of O(2)H***O(6) and O(3)H***O(5) intramolecular hydrogen bondings, respectively. In addition, THF could protect and transfer the cellulose-derived products to organic phase through forming hydrogen bonding between oxygen atom in THF and hydrogen atom of C4-O-H in glucose or aldehyde group in 5-hydroxymethylfurfural (HMF), which can lead more NaCl to combine with -OH of M-cellulose and further disrupt hydrogen bonds in M-cellulose, thereby improving the yield of small molecular weight products (especially HMF) and further promoting the dissolution of cellulose. As a cheap and reusable system, NaCl-H2O-THF system may be a promising approach for the dissolution and further conversion of cellulose in lignocellulosic biomass without any enzymes, ionic liquid nor conventional catalyst.
      PubDate: 2017-11-17T04:55:24.735051-05:
      DOI: 10.1002/cssc.201701861
       
  • Catalytic Transfer Hydrogenation of Biomass-Derived Carbonyls over
           Hafnium-Based Metal-Organic Frameworks
    • Authors: Avelino Corma; Pilar García-García, Sergio Rojas-Buzo
      Abstract: A series of highly crystalline, porous, hafnium-based metal-organic frameworks (MOFs) have shown to catalyze the transfer hydrogenation reaction of levulinic ester to produce γ-valerolactone using isopropanol as hydrogen donor and the results are compared with the zirconium-based counterparts. The role of the metal center in Hf-MOFs has been identified and reaction parameters optimized. NMR studies with isotopically labeled isopropanol evidences that the transfer hydrogenation occurs via a direct intermolecular hydrogen transfer route. The catalyst, Hf-MOF-808, can be recycled several times with only a minor decrease in catalytic activity. Generality of the procedure was shown by accomplishing the transformation with aldehydes, ketones and α,β-unsaturated carbonyl compounds. The combination of Hf-MOF-808 with the Brønsted acidic Al-Beta zeolite gives the four-step one-pot transformation of furfural to γ-valerolactone in good yield of 72%.
      PubDate: 2017-11-15T06:50:23.736792-05:
      DOI: 10.1002/cssc.201701708
       
  • Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of
           Lignin over Super Lewis Acid Combined with Metal Catalysts
    • Authors: Hongliang Wang; Huamin Wang, Eric Kuhn, Melvin P. Tucker, Bin Yang
      Abstract: Super Lewis acids containing the triflate anion [e.g., Hf(OTf)4, Ln(OTf)3, In(OTf)3, Al(OTf)3] and noble metal catalysts (e.g., Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalyzed by super Lewis acids.The biggest Lewiser: Super Lewis acids and noble metals form an efficient catalytic system that can overcome the energy barrier for conversion of lignin into high yield jet-fuel range hydrocarbons. Metal triflates mediate rapid ether bond cleavage through selective bonding to the etheric oxygen, whereas the noble metal catalyzes the subsequent hydrogenation reaction, eliminating functional groups.
      PubDate: 2017-11-14T12:45:22.716058-05:
      DOI: 10.1002/cssc.201701567
       
  • Role of bismuth in the electro-kinetics of silicon photocathodes for solar
           rechargeable vanadium redox flow batteries
    • Authors: Cristina Flox; Sebastián Murcia-López, Nina M. Carretero, Carles Ros, Juan Ramón Morante, Teresa Andreu
      Abstract: The ability of crystalline Si to photo-assist the V3+/V2+ cathodic reaction under simulated solar irradiation, combined with the effect of Bi have led to important electrochemical improvements. Besides the photo-voltage supplied by the photovoltaics, additional decrease in the onset potentials, high reversibility of the V3+/V2+ redox pair and improvement in the electro-kinetics have been attained thanks to the addition of Bi. In fact, Bi0 deposition has shown to slightly decrease the photocurrent, but the significant betterment in the charge transfer, reflected in the overall electrochemical performance clearly justifies its use as additive in a photo-assisted system for maximizing the efficiency of solar charge to battery.
      PubDate: 2017-11-14T09:51:00.424496-05:
      DOI: 10.1002/cssc.201701879
       
  • Corrigendum: Highly Active N,O Zinc Guanidine Catalysts for the
           Ring-Opening Polymerization of Lactide
    • Authors: Pascal M. Schäfer; Martin Fuchs, Andreas Ohligschläger, Ruth Rittinghaus, Paul McKeown, Enver Akin, Maximilian Schmidt, Alexander Hoffmann, Marcel A. Liauw, Matthew D. Jones, Sonja Herres-Pawlis
      PubDate: 2017-11-14T05:50:20.554383-05:
      DOI: 10.1002/cssc.201702066
       
  • The three-dimensional-structure of twisted benzo[ghi]perylene-triimide
           dimer as a non-fullerene acceptor for inverted perovskite solar cells
    • Authors: Priyadharsini Karuppuswamy; Hung-Cheng Chen, Pen-Cheng Wang, Chao-Ping Hsu, Ken-Tsung Wong, Chih Wei Chu
      Abstract: In this work, we introduced benzo[ghi]perylenetriimide (BPTI) derivatives including monomer and twisted dimer (t-BPTI) as an alternative electron transport layer (ETL) material to replace the commonly used PC61BM in inverted planar heterojunction perovskite solar cells. Moreover, the double ETL layer was applied in our perovskite solar cells with structure of glass/ITO/PEDOT:PSS/perovskite/BPTI/C60 or PDI-C4/BCP/Al. Use of a double ETL layer structure can effectively eliminate the leakage current. The devices with the t-BPTI/C60 double ETL layer yield an average power conversion efficiency of 10.73% and a maximum efficiency of 11.63%. The device based on the complete non-fullerene electron acceptors of t-BPTI/PDI-C4 as double ETL achieved maximum efficiency of 10.0%. Besides, it is found that the utilization of alloy t-BPTI+BPTI as ETL can effectively reduce the hysteresis effect of perovskite solar cells. The results suggest that BPTI based electron transport materials are potential alternatives for widely used fullerene acceptors in PSCs.
      PubDate: 2017-11-12T22:45:24.902476-05:
      DOI: 10.1002/cssc.201701827
       
  • Ruthenium Ion-Complexed Graphitic Carbon Nitride Nanosheets Supported on
           Reduced Graphene Oxide as High-Performance Catalysts for Electrochemical
           Hydrogen Evolution
    • Authors: Shaowei Chen; Yi Peng, Wanzhang Pan, Nan Wang, Jia-En Lu
      Abstract: Carbon-based materials are promising, low-cost electrocatalysts toward hydrogen evolution reaction (HER), although the catalytic performance needs to be further improved before commercialization. In this study, ruthenium ions are incorporated into carbon nitride-reduced graphene oxide hybrids forming C3N4-rGO-Ru composites through RuN coordination. The incorporation of Ru ions, at a loading of 1.93 at.%, leads to electron redistribution within the materials and dramatically enhances the HER performance, as compared to C3N4, C3N4-rGO, and C3N4-Ru, with an overpotential of only 80 mV to reach the current density of 10 mA/cm2, a Tafel slope of 55 mV/dec, and an exchange current density of 0.462 mA/cm2. This performance is highly comparable to that of Pt/C, and ascribed to the positive shift of the conduction band of the composite, where the charge carrier density increases by over 200 times, as compared to that of C3N4, leading to a lower energy barrier of hydrogen evolution. The results suggest a new strategy in the design and engineering of functional nanocomposites for effective HER electrocatalysis by embedding select metal ions into the carbon-based molecular skeletons.
      PubDate: 2017-11-09T14:25:38.553431-05:
      DOI: 10.1002/cssc.201701880
       
  • Sugar Poly(orthoester) Underwent a Complete Cycle of Depolymerization and
           Repolymerization
    • Authors: Wenjun Du; Lingyao Li, Sampa Maiti, Nicole A Thompson, Lan J Miligan
      Abstract: The capability of a polymer to depolymerize, which regenerates its original monomer for further polymerization, is very attractive in terms of sustainability. Sugar poly(orthoester) was recently synthesized as a novel class of glycopolymer. The high sensitivity of the backbone orthoester linkage towards acidolysis provides a valuable model to study its depolymerization. Herein, we report that the sugar poly(orthoester) can be completely depolymerized at slightly acidic conditions. However, in most cases, the depolymerization gave a stable cyclic product (1,6-anhydro glucopyranose), instead of its original monomer. We discovered that the formation of the cyclic 1,6-anhydro glucopyranose was both kinetically- and thermodynamically-favored. However, this pathway could be shut down by chemically deactivating a key intermediate; shifting the reaction pathway that favors the formation of the original monomer. We further demonstrate that the regenerated monomer can be repolymerized efficiently.
      PubDate: 2017-11-09T08:25:40.396691-05:
      DOI: 10.1002/cssc.201701870
       
  • Isocyanate-free approach to water-borne polyurea dispersions and coatings
    • Authors: Shuang Ma; Ellen van Heeswijk, Bart Noordover, Rafael Sablong, Rolf van Benthem, Cor Koning
      Abstract: In this work, an isocyanate-free approach to produce polyureas from diamines and dicarbamates as monomers is reported. A side reaction limiting molecular weight during the diamine/dicarbamate polymerization, viz. N-alkylation of amine end-groups, is investigated. Mitigation of the N-alkylation, either by enhancing the carbamate aminolysis rate or by substitution of dimethylcarbamates with more sterically hindered diethylcarbamates, affords polyureas with sufficiently high molecular weights to assure satisfactory mechanical properties. Stable polyurea dispersions with polyamines as internal dispersing agents are prepared, and the properties of the corresponding coatings are evaluated.
      PubDate: 2017-11-08T09:56:13.891588-05:
      DOI: 10.1002/cssc.201701930
       
  • Molybdenum-doping augments platinum-copper oxygen reduction
           electrocatalyst
    • Authors: Nicolas Alonso-Vante; Yun Luo, Björn Kirchhoff, Donato Fantauzzi, Laura Calvillo, Luis Alberto Estudillo-Wong, Gaetano Granozzi, Timo Jacob
      Abstract: Improving the efficiency of Pt-based oxygen reduction reaction (ORR) catalysts while also reducing costs remains an important challenge in energy research. To this end, we synthesized highly stable and active carbon-supported Mo-doped PtCu (Mo-PtCu/C) nanoparticles (NPs) from readily available precursors in a facile one-pot reaction. Mo-PtCu/C displays two- to four-fold higher ORR half-cell kinetics than reference PtCu/C and Pt/C materials - a trend which was confirmed in proof-of-concept experiments using a H2/O2 micro-laminar fuel cell. This Mo-induced activity increase mirrors observations for Mo-PtNi/C NPs and possibly suggests an emerging trend. Electrochemical accelerated stability tests revealed that dealloying is greatly reduced in Mo-PtCu/C in contrast to the binaries PtCu/C and PtMo/C. Supporting DFT studies suggest that Mo-PtCu's exceptional stability can be attributed to oxidative resistance of Mo-doped atoms. Furthermore, our calculations revealed that oxygen can induce segregation of Mo to the catalytic surface where it effects beneficial changes to the surface's oxygen adsorption energetics in context of the Sabatier principle.
      PubDate: 2017-11-07T13:20:25.974927-05:
      DOI: 10.1002/cssc.201701822
       
  • WtF-Nano: One-pot dewatering and water-free topochemical modification of
           nanocellulose in ionic liquids or gamma-valerolactone
    • Authors: Tiina Laaksonen; Jussi Kari Juhani Helminen, Laura Lemetti, Jesper Långbacka, Daniel Rico del Cerro, Michael Hummel, Erkko Ilari Filpponen, Antti Rantamäki, Tia Kakko, Marianna Kemell, Susanne Wiedmer, Sami Heikkinen, Ilkka Kilpeläinen, Alistair William Thomas King
      Abstract: It is shown that ionic liquids can be used to dewater birch kraft pulp cellulose nanofibrillar (CNF) suspension and act as a medium for water-free topochemical modification of the nanocellulose. Acetylation, was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of ionic liquid or molecular co-solvent. However, the viscoelastic properties of CNF suspended in two ionic liquids showed that the more basic, but non-dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterials tests showed that all ionic liquids in this study were harmless. Scanning electron microscopy and wide-angle X-ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1D and 2D NMR analysis, after direct dissolution in a novel ionic liquid electrolyte solution, identified that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters
      PubDate: 2017-11-07T08:50:26.592197-05:
      DOI: 10.1002/cssc.201701344
       
  • A New Pentiptycene-Based Dianhydride and Its High-Free-Volume Polymer for
           CO2 Removal
    • Authors: Ahmad Arabi Shamsabadi; Farzad Seidi, Mohammad Nozari, Masoud Soroush
      Abstract: In addition to possessing excellent chemical, mechanical and thermal stability, polyimides and polyetherimides have excellent solubility in many solvents, rendering them suitable for membrane preparation. In this paper, we report the synthesis and characterization of two new monomers [a pentiptycene-based dianhydride (PPDAn) and a pentiptycene imide-containing diamine (PPImDA)], and a pentiptycene-based polyimide [PPImDA-4, 4′-hexafluoroisopropylidene diphthalic anhydride (PPImDA-6FDA)]. The products are characterized using FTIR, 1H NMR, GPC, mass spectroscopy, XPS, TGA, DSC, BET, and XRD. The high molecular-weight PPImDA-6FDA has remarkable thermal stability and excellent solubility in common organic solvents. It also has an extraordinarily high fractional free-volume (0.233) due to the presence of −C(CF3)2− units, the rigid diamine, and the pentiptycene moiety in the polymer structure. It has a high CO2 permeability (812 Barrer) due to its poor chain-packing caused by its rigid groups veiling the influence of the etheric oxygen in its backbone. It has the highest CO2 permeability among all reported pentiptycene-containing polymers (about 6 times higher than the most permeable one) without sacrificing the selectivity. The high free-volume, good microporosity, high solubility in many solvents, and remarkable thermal stability of PPImDA-6FDA point to the great potential of this polymer for CO2 removal.
      PubDate: 2017-11-06T01:15:29.71814-05:0
      DOI: 10.1002/cssc.201701491
       
  • Hierarchical Core-Shell Nickel Cobaltite Chestnut-like Structures as High
           Activity Bi-functional Catalysts for Rechargeable Metal-Air Batteries
    • Authors: Dong Un Lee; Moon Gyu Park, Zachary Paul Cano, Wook Ahn, Zhongwei Chen
      Abstract: Nano-engineered hierarchical core-shell chestnut-like structures have been successfully synthesized as a bi-functionally active electrocatalyst for rechargeable metal-air battery applications. Both the morphology and composition of the catalyst have been optimized by the facile hydrothermal reaction, resulting in the 10-hour treated sample to perform significantly enhanced activity towards facilitating both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Specifically, the catalyst demonstrated -0.28, and 0.60 V vs. SCE at the ORR half-wave potential and the OER current density of 10 mA cm-2, respectively. The resulting ORR/OER potential difference of 0.90 V was the smallest among other catalysts synthesized at 2, 6, and 12 hours. The excellent bi-functional activity of the catalyst is attributed to the nano-scale porous morphology and the spinel nickel cobaltite composition, which improved the active site exposure and transport of reactants and charges during the oxygen reactions.
      PubDate: 2017-11-05T21:55:36.914228-05:
      DOI: 10.1002/cssc.201701832
       
  • High lithium insertion voltage single-crystal H2Ti12O25 nanorods as high
           capacity and high rate lithium-ion battery anode material
    • Authors: Qiang Guo; Li Chen, Zizhao Shan, Wee Siang Vincent Lee, Wen Xiao, Zhifang Liu, Jingjing Liang, Gaoli Yang, Junmin Xue
      Abstract: H2Ti12O25 holds great promise as high voltage anode material for advanced lithium-ion battery application. In order to enhance its electrochemical performance, controlling crystal orientation and morphology is one of the effective ways to cope the slow Li+ diffusion inside H2Ti12O25 with severe anisotropy. In this report, Na2Ti6O13 nanorods, prepared with Na2CO3 and anatase TiO2 in molten NaCl medium, were used as a precursor in the synthesis of long single-crystal H2Ti12O25 nanorods with reactive facets. As-prepared H2Ti12O25 nanorods with the diameter of 100-200 nm show higher charge (extraction) specific capacity and better rate performance as compared to the previously reported system. The reversible capacity of H2Ti12O25 was 219.8 mAh g-1 at 1C after 100 cycles, 172.1 mAh g-1 at 10 C and 144.4 mAh g-1 at 20 C after 200 cycles, respectively, which were higher than those of H2Ti12O25 prepared by conventional soft-chemical method. Moreover, as-prepared H2Ti12O25 nanorods exhibited superior cycle stability of more than 94% capacity retention with a nearly 100% coulombic efficiency, after 100 cycles at 1C. Based on the above results, long single-crystal H2Ti12O25 nanorods synthesized in molten NaCl with outstanding electrochemical characteristic holds a significant amount of promise for hybrid electric vehicles and energy storage system.
      PubDate: 2017-11-04T07:25:31.62671-05:0
      DOI: 10.1002/cssc.201701479
       
  • H2-assisted CO2 thermochemical reduction on La0.9Ca0.1FeO3-δ
           membranes: a kinetics study
    • Authors: Xiao-Yu Wu; Ahmed F. Ghoniem
      Abstract: Kinetics data for CO2 thermochemical reduction in an isothermal membrane reactor is required to identify the rate-limiting steps. Here, we report a detailed reaction kinetics study on this process supported by an La0.9Ca0.1FeO3-δ (LCF-91) membrane. The dependence of CO2 reduction rate on various operating conditions is examined such as CO2 concentration on the feed side, fuel concentrations on the sweep side and temperatures. CO2 reduction rate is proportional to the oxygen flux across the membrane, and the measured maximum fluxes are 0.191 and 0.164 μmol cm-2 s-1 with 9.5% H2 and 11.6% CO on the sweep side at 990oC, respectively. Fuel is used to maintain the chemical potential gradient across the membrane and CO is used by construction to derive the surface reaction kinetics. This membrane also exhibits stable performances for 106 hours. A resistance-network model is developed to describe the oxygen transport process and the kinetics data are parameterized using the experimental values. The model shows a transition of the rate limiting step between the surface reactions on the feed side and the sweep side depending on the operating conditions.
      PubDate: 2017-11-04T00:30:29.307743-05:
      DOI: 10.1002/cssc.201701372
       
  • Electrochemical Synthesis of Ammonia from Water and Nitrogen: A
           Lithium-Mediated Approach Using Lithium-Ion Conducting Glass Ceramic
    • Authors: Kwiyong Kim; Seung Jong Lee, Dong-Yeon Kim, Chung-Yul Yoo, Jang Wook Choi, Jong-Nam Kim, Youngmin Woo, Hyung Chul Yoon, Jong-In Han
      Abstract: Lithium-mediated reduction of dinitrogen is a promising way to evade electron-stealing hydrogen evolution, a critical challenge which limits faradaic efficiency (FE) and thus hinders the success of traditional protic solvent-based ammonia electro-synthesis. In this study, we propose a viable illustration to realize the lithium-mediated pathway using lithium-ion conducting glass ceramic, which can be divided into three successive steps: (i) lithium deposition, (ii) nitridation, and (iii) ammonia formation. Ammonia was successfully synthesized from molecular nitrogen and water, yielding a maximum FE of 52.3%. With a comparable ammonia synthesis rate to previously reported approaches, the fairly high FE demonstrates the possibility of using this nitrogen fixation strategy as a substitute for the firmly established, yet exceedingly complicated and expensive technology, and in so doing represents a next-generation energy storage system.
      PubDate: 2017-11-03T09:55:28.071443-05:
      DOI: 10.1002/cssc.201701975
       
  • Binder-free hybrid titanium-niobium oxide/carbon nanofiber mats for
           lithium-ion battery electrodes
    • Authors: Aura Tolosa; Simon Fleischmann, Ingrid Grobelsek, Antje Quade, Eunho Lim, Volker Presser
      Abstract: This study introduces the synthesis of free-standing, binder-free, titanium-niobium oxide/carbon hybrid nanofibers for Li-ion battery applications. The one-pot synthesis offers a significant reduction of processing steps and avoids the use of environmentally unfriendly binder materials, making the approach highly sustainable. Tetragonal Nb2O5/C and monoclinic Ti2Nb10O29/C hybrid nanofibers synthesized at 1000 °C presented the highest electrochemical performance, with capacity values of 243 and 267 mAh∙g-1, respectively normalized to the electrode mass. At 5 A∙g-1, the Nb2O5/C and Ti2Nb10O29/C hybrid fibers maintained 78% and 53 % of the initial capacity, respectively. The higher rate performance and stability of tetragonal Nb2O5, compared to monoclinic Ti2Nb10O29, relates to the low energy barriers for Li+ transport in this crystal structure, with no phase transformation. The improved rate performance resulted from the excellent charge propagation in the continuous nanofiber network.
      PubDate: 2017-11-03T03:55:51.587337-05:
      DOI: 10.1002/cssc.201701927
       
  • Hard carbons for sodium ion battery anodes: Synthetic strategies, material
           properties, and storage mechanisms
    • Authors: Malik Wahid; Dhanya Puthusseri, Yogesh Gawli, Neha Sharma, Satishchandra B. Ogale
      Abstract: Na-ion batteries are attracting great interest lately due to their potential as viable future alternatives for Li-ion batteries in view of much higher earth abundance of Na over Li. Although both the battery systems have basically similar chemistries, the key celebrated negative electrode in Li-battery, namely graphite, is unavailable for Na-ion battery due to larger size of Na-ion. This need is satisfied by the so-called "hard carbon" which can internalize the larger Na-ion and has the desirable electrochemical properties. Unlike graphite with its specific layered structure however, hard carbon occurs in diverse microstructural states. In this mini-review we seek to elucidate the connections between precursor choices, synthetic protocols, microstructural states, and performance features of hard carbon forms in the context of Na-ion battery application. Deriving from the pertinent literature employing classical and modern structural characterization techniques, we discuss various issues related to microstructure, morphology, defects, and heteroatom doping. Finally, an outlook is presented suggesting the emergent research directions.
      PubDate: 2017-11-03T02:55:28.055838-05:
      DOI: 10.1002/cssc.201701664
       
  • Production of Low-Freezing-Point Highly Branched Alkanes via Michael
           Addition
    • Authors: Yanqin Wang; Yaxuan Jing, Qineng Xia, Xiaohui Liu
      Abstract: A new approach for the production of low freezing point, high-quality fuels from lignocellulose derived molecules was developed with Michael addition as the key step. Among the investigated catalysts, CoCl2*6H2O was found to be the most active for Michael addition of 2,4-pentanedione with FA (single aldol adduct of furfural and acetone, 4-(2-furanyl)-3-butene-2-one). Over CoCl2*6H2O, a high carbon yield of C13 oxygenates (about 75%) can be achieved under mild conditions (353 K, 20 h). After hydrodeoxygenation, low freezing point (< 223 K) branched alkanes with 13 carbons within jet fuel ranges were obtained over Pd/NbOPO4 catalyst. Furthermore, C18,23 fuel precursors could be easily synthesized through Michael addition of 2,4-pentanedione with DFA (double-condensation product of furfural and acetone) under mild conditions and the molar ratio of C18/C23 is dependent on the reaction conditions of Michael addition. After hydrodeoxygenation, high density (0.8415 g/ml) and low freezing point (< 223 K) branched alkanes with 18, 23 carbons with lubricant range were also obtained over Pd/NbOPO4 catalyst. These highly branched alkanes can be directly used as transportation fuels or additives. This work opens a novel strategy for the synthesis of highly branched alkanes with low-freezing-point from renewable biomass.
      PubDate: 2017-11-02T22:01:36.231912-05:
      DOI: 10.1002/cssc.201701789
       
  • Multiple trapping model for the charge recombination dynamics in
           mesoporous-structured perovskite solar cells
    • Authors: Hao-Yi Wang; Yi Wang, Ming-Yang Hao, Yujun Qin, Li-Min Fu, Zhi-Xin Guo, Xi-Cheng Ai, Jian-Ping Zhang
      Abstract: The photovoltaic performance of organic-inorganic hybrid perovskite solar cells has reached a bottleneck after the rapid development in last few years, and further breakthrough requires a deeper understanding about the underlying mechanism of the photoelectric conversion process in the device, especially the dynamics of charge carrier recombination. Originated from dye-sensitized solar cells (DSSCs), mesoporous-structured perovskite solar cells (MPSCs) have shown obvious similarity in the photoelectric dynamics with DSSCs in many aspects. Herein, by incorporating the classic multiple trapping model of the charge recombination dynamic process for DSSCs into MPSCs with rational modification, a novel physical model is proposed to describe the dynamics of charge recombination in MPSCs, which exhibits good agreement with the experimental data. Accordingly, the perovskite-dominating and the TiO₂-dominating charge recombination processes are assigned, respectively, and their relationships with the trap-state distribution are also discussed. An optimal balance between these two dynamic processes is required for the performance improvement of the mesoporous-structured perovskite device.
      PubDate: 2017-11-02T03:26:00.096328-05:
      DOI: 10.1002/cssc.201701780
       
  • Highly Efficient and Robust Enantioselective Liquid-Liquid Extraction of
           1,2-Amino Alcohols Utilising VAPOL- and VANOL-based Phosphoric Acid Hosts.
           
    • Authors: Johannes Gerardus de Vries; Erik B. Pinxterhuis, Jean-Baptiste Gualtierotti, Sander J. Wezenberg, Ben L. Feringa
      Abstract: The large-scale production of enantiopure compounds in a cost-effective and environmentally friendly manner remains one of the major challenges of modern day chemistry. The resolution of racemates via enantioselective liquid-liquid extraction was developed as a suitable solution but has remained largely underused due to a lack of highly efficient and robust chiral hosts to mediate the process. This paucity of hosts can in part be attributed to a feeble understanding of the underlying principles behind these processes hindering the design of more efficient selectors. Herein, we present an in depths study of a previously untested class of hosts, VAPOL and VANOL derived phosphoric acids, for the efficient enantioselective liquid-liquid extraction of 1,2-amino alcohols. A systematic investigation of extraction parameters was conducted revealing many key interactions, while DFT calculations illustrate the binding modes for the 1:1 complexes that are involved in chiral recognition. The resulting, now optimised, procedures, are highly robust and easy to implement. They are also easily scalable as was demonstrated by U-tube experiments.
      PubDate: 2017-11-01T12:20:33.787357-05:
      DOI: 10.1002/cssc.201701896
       
  • Selective Liaison With Liquids for Environment-Friendly and Comprehensive
           Oil/Water Separation
    • Authors: Dibyangana Parbat; Uttam Manna
      Abstract: A hydrophobic three dimensional material—having smart affair with oil phase, is developed using a scalable and facile Micheal addition reaction at ambient condition, without using any catalyst. The synthesized material is capable of absorbing both heavy/light oils with efficiency above 1000 weight %. This super-oil-absorbance property remained intact in diverse scenarios, including extremes of temperature (100°C and 10°C), pressure (184.7mbar), and prolonged (7 days) exposures to extremes of pH (1/12), surfactants (DTAB/SDS, 1mM)-contaminated water, artificial sea water etc. This super-oil-absorbent with impeccable durability was exploited further in demonstrations of comprehensive and facile clean-up from various forms of oil/water mixtures (i.e., floating oil, sediment oil, emulsions etc.) in extremes and complex settings that are relevant to practical scenarios including marine-oil-spills, following eco-friendly and energy-efficient selective-absorption/active-filtration principles.
      PubDate: 2017-10-30T06:08:32.056761-05:
      DOI: 10.1002/cssc.201701791
       
  • A functional hydrogenase mimic chemisorbed onto FTO electrodes; a strategy
           towards water splitting devices
    • Authors: riccardo Zaffaroni; Remko Detz, Jarl Ivar van der Vlugt, Joost Reek
      Abstract: In this contribution, we describe the preparation, characterization and immobilization studies of a benzene dithiolale di-iron hydrogen evolving catalyst, first step towards the development of water splitting devices based on molecular components. FTO (fluorine doped tin oxide), was chosen as the preferred electrode material due to its conductive properties and electrochemical stability. We also report, the use of FTO nano-crystals to greatly improve the surface area of commercially available FTO whilst preserving the properties of the material. Catalyst modified electrodes are shown to be competent for electrocatalytic hydrogen evolution from acidic aqueous media at relatively low overpotential (500 mV) with a Faradaic efficiency close to unity, representing the first hydrogen evolving electrodes based on di-iron hydrogenase synthetic models. We show that the catalyst operates at roughly 160 mV lower overpotentials, yet with similar rates, when immobilized onto the electrode surface.
      PubDate: 2017-10-27T10:35:40.077056-05:
      DOI: 10.1002/cssc.201701757
       
  • Review of natural product-derived carbon dots: from natural products to
           functional materials
    • Authors: Xinyue Zhang; Mingyue Jiang, Na Niu, Zhijun Chen, Shujun Li, Shouxin Liu, Jian Li
      Abstract: Nature provides an almost limitless supply of natural sources, which inspires scientists to develop new materials with novel applications and less environmental impact. Recently, much attention has focused on preparing natural product-derived carbon dots (NCDs) because of several advantages of natural products. First of all, natural products are renewable and have good biocompatibility. Secondly, Natural products contain heteroatoms, which facilitates the fabrication of heteroatom-doped NCDs without addition of external heteroatom sources. Finally, some natural products can be used to prepare NCDs in very green and simple way, compared to traditional methods for carbon dots from man-made carbon sources. NCDs have shown tremendous potential in many fields, including biosensing, bioimaging, optoelectronics and photocatalysis. However, there have been no reviews that specifically cover NCDs. To address this deficiency, we now provide a review of recent progress in the synthesis, properties and applications of NCDs. The challenges and future direction of NCD-based materials research in this booming field will also be discussed.
      PubDate: 2017-10-26T04:30:26.139026-05:
      DOI: 10.1002/cssc.201701847
       
  • Sodium-Containing Spinel Zinc Ferrite as a Catalyst Precursor for the
           Selective Synthesis of Liquid Hydrocarbon Fuels
    • Authors: Yo Han Choi; Eun Cheol Ra, Eun Hyup Kim, Kwang Young Kim, Youn Jeong Jang, Kyeong-Nam Kang, Sun Hee Choi, Ji-Hyun Jang, Jae Sung Lee
      Abstract: A microwave-assisted hydrothermal synthesis produces ZnFe2O4 containing Na residue as a precursor to a CO2 hydrogenation catalyst that displays high CO2 conversion and high selectivity to liquid hydrocarbon products in the gasoline and diesel range with high olefin-to-paraffin ratios. Compared to reference catalysts derived from Fe2O3 and a ZnO–Fe2O3 physical mixture, the ZnFe2O4-derived catalyst contains well-dispersed iron particles with Zn serving as a structural promoter. A profound effect of the residual Na as an electronic promoter is also observed, which improves the selectivity for C5+ hydrocarbons and olefins. The ZnFe2O4-derived catalyst exhibits excellent performance in the CO2 Fischer–Tropsch reaction as it forms the active Hägg iron carbide (χ-Fe5C2) phase readily through the in situ carburization of iron.It's a gas: A catalyst derived from spinel ZnFe2O4 containing Na residue displays high CO2 hydrogenation activity and liquid-fuel selectivity in the gasoline and diesel range with high olefin-to-paraffin ratios.
      PubDate: 2017-10-25T10:08:16.371312-05:
      DOI: 10.1002/cssc.201701437
       
  • Adsorption and selective recovery of citric acid with
           poly(4-vinylpyridine)
    • Authors: Matthias Van den Bergh; Ben Van de Voorde, Dirk De Vos
      Abstract: Citric acid (CA) is an important organic acid that is produced on a large scale by fermentation. Current methods to recover CA from the fermentation broth require large amounts of chemicals and produce considerable amounts of waste, while not all CA can be recovered. The use of adsorbents can increase the degree of product recovery and reduce chemical consumption and waste generation. In this work poly(4-vinylpyridine) (PVP) is evaluated as adsorbent for CA recovery. It has a high adsorption capacity (>30 wt%) at low pH and a high selectivity for CA at moderate pH in the presence of sulphate anions, two conditions that are frequently encountered during CA recovery. PVP could be efficiently regenerated after adsorption using simple alcohols like methanol and ethanol. Considering selectivity and regeneration, PVP distinctly outperforms more common adsorbents for organic acids, like commercial strongly and weakly basic anion exchangers. The desirable adsorptive features of PVP for CA can be attributed to the low basicity of the pyridine group.
      PubDate: 2017-10-24T10:50:29.263861-05:
      DOI: 10.1002/cssc.201701672
       
  • Reconsidering water electrolysis: producing H2 at cathodes together with
           valuable chemicals at anodes. Selective anodic oxidation of n-butylamine
           to n-butyronitrile as an example
    • Authors: Song Xue; Sebastian Watzele, Victor Čolić, Kurt Brandl, Batyr Garlyyev, Aliaksandr Bandarenka
      Abstract: Electrocatalysis of the oxygen evolution reaction is of great interest for improving the effectiveness of water splitting devices. Decreasing the anodic overpotential and simultaneously changing anode reaction selectively, producing valuable chemicals instead of O2, would be a major improvement of the overall cost efficiency. Recently it was shown that some amines, when present in aqueous electrolytes, change the selectivity of the anodic process generating H2O2 rather than O2 on MnOx at pH=10. This results in unusually high apparent "anodic activities". In this work, we show industrially relevant OER catalysts: oxy-hydroxides of cobalt (CoOx), nickel/iron (NiFeOx) and nickel (NiOx) all show more pronounced effects; also by using these catalysts we selectively produce n-butyronitrile from n-butylamine at higher pHs as an easily retrievable valuable product. The pH-dependence of the activity was investigated at pH values, closer to ones at which alkaline electrolyzers operate. The highest activities were observed for NiOx thin film electrodes at pH=12 in presence of 0.4M n-butylamonium sulfate, without poisoning the active sites of Pt electrocatalysts from the hydrogen evolution electrode side. 1H-NMR showed that n-butylamine is selectively oxidized to n-butyronitrile, an organic chemical with numerous applications. However, the measurements using rotating ring-disk electrodes also provide a proof that some H2O2 is also generated at the surface of the oxide anodes.
      PubDate: 2017-10-24T04:00:56.266506-05:
      DOI: 10.1002/cssc.201701802
       
  • Ligand Controlled Electrodeposition of Highly Intrinsic Active and
           Optically Transparent NiFeOxHy Film as Electrocatalytic Water Oxidation
           Catalyst
    • Authors: Husileng Lee; Xiujuan Wu, Xiaonan Yang, Licheng Sun
      Abstract: A highly intrinsic active and optically transparent NiFeOxHy water oxidation catalyst was prepared by electrodeposition of [Ni(C12-tpen)](ClO4)2 complex (Ni-C12). This NiFeOxHy film exhibits a current density of 10 mA cm-2 with an overpotential (η) of only 298 mV at nanomolar concentration and the current density of 10 mA cm-2 remains constant over 20 h in 1 M KOH. The extremely high TOFs of 0.51 s-1 was obtained with η of 300 mV. More importantly, such outstanding activity and transparency (optical loss < 0.5%) of NiFeOxHy film are attributed to ligand effect of dodecyl substituent in Ni-C12 complex which enable its future application in solar water splitting.
      PubDate: 2017-10-22T20:55:35.872841-05:
      DOI: 10.1002/cssc.201701869
       
  • Imidazolium- and triazine-based porous organic polymers for heterogeneous
           catalytic conversion of CO2 into cyclic carbonates.
    • Authors: Hong Zhong; Yanqing Su, Xingwei Chen, Xiaoju Li, Ruihu Wang
      Abstract: Carbon dioxide (CO2) adsorption and concomitant catalytic conversion into useful chemicals are promising approaches to alleviate energy crisis and global warming. It is highly desirable for developing new types of heterogeneous catalytic materials containing CO2-philic groups and catalytic active sites for CO2 chemical transformation. Here, we present an imidazolium- and triazine-based porous organic polymer with counter chloride anion (IT-POP-1). The porosity and CO2 affinity of IT-POP-1 may be modulated at molecular level through facile anion exchange strategy. Compared with the post-modified polymers with iodide and hexafluorophosphate anions, IT-POP-1 possesses the highest surface area and the best CO2 uptake capacity with excellent adsorption selectivity over N2. The roles of the task-specific components, such as triazine, imidazolium, hydroxyl and counter anions, in CO2 absorption and catalytic performance were illustrated. IT-POP-1 exhibits the highest catalytic activity and excellent recyclability in solvent- and additive-free cycloaddition reaction of CO2 with epoxides.
      PubDate: 2017-10-20T03:20:37.864441-05:
      DOI: 10.1002/cssc.201701821
       
  • Imidazolium based Ionic liquids as efficient reagents for lignin C-O bond
           cleavage
    • Authors: Marina Thierry; Amel Majira, Bruce Pégot, Laurent Cézard, Flavien Bourdreux, Gilles Clément, François Perreau, Stéphanie Boutet-Mercey, Patrick Diter, Giang Vo-Thanh, Catherine Lapierre, Paul-Henri Ducrot, Emmanuel Magnier, Stephanie Baumberger, betty cottyn
      Abstract: Lignin chemical demethylation in ionic liquids was investigated using pure lignin-model monomers and dimer together with dioxan isolated lignins from poplar, miscanthus and maize. Different methylimidazolium ionic liquids (ILs) were compared, according to two different heating processes, microwave irradiation and conventional heating in sealed tube. The conversion yield and influence of the treatments on lignin structure were assessed by 31P NMR, size exclusion chromatography and thioacidolysis. The acidic IL [HMIM][Br] was shown to be an effective combination solvent/reagent for the demethylation and even depolymerisation of lignin. The relatively mild reaction conditions, the clean work-up, and the ability to reuse the ionic liquid made the described procedure an attractive and new green method for the lignin conversion to produce phenol-rich lignin oligomers.
      PubDate: 2017-10-19T04:45:35.953679-05:
      DOI: 10.1002/cssc.201701668
       
  • Direct coupling of thermo- and photo-catalytic conversion of
           CO₂-H₂O to fuels
    • Authors: Li Zhang; Guoguo Kong, Yaping Meng, Jinshu Tian, Lijie Zhang, Shaolong Wan, Jingdong Lin, Yong Wang
      Abstract: Photocatalytic CO₂ reduction into renewable hydrocarbon solar fuels is considered as a promising strategy to simultaneously address the global energy and environmental issues. This article focuses on the direct coupling of photocatalytic water splitting and thermo-catalytic hydrogenation of CO₂ in the conversion of CO₂-H₂O to fuels. Specifically, it was found that direct coupling of thermo- and photo-catalysis over Au-Ru/TiO₂ leads to 15 times higher activity (358 K, with ~99% CH₄ selectivity) in the conversion of CO₂-H₂O to fuels than that of photo-catalytic water splitting. This is ascribed to the promoting effect of thermo-catalytic hydrogenation of CO₂ by hydrogen atoms generated in situ by photo-catalytic water splitting.
      PubDate: 2017-10-18T01:15:56.517182-05:
      DOI: 10.1002/cssc.201701472
       
  • Electrochemical Behavior of Pyridinium and N-Methyl Pyridinium Cations in
           Aqueous Electrolyte for CO2 Reduction
    • Authors: Estelle Lebègue; Julia Agullo, Daniel Bélanger
      Abstract: We examined the electrochemical reduction of aqueous pyridinium and N-methyl pyridinium ions in the absence and presence of CO2 and studied the electrolysis reaction products on glassy carbon, Au and Pt electrodes. Unlike pyridinium, N-methyl pyridinium is not electroactive at the Pt electrode. The electrochemical reduction of the two pyridine derivatives was found to be irreversible on glassy carbon. These results confirmed the essential role of the N-H bond of the pyridinium cation. In contrast, the electrochemical response of N-methyl pyridinium ion at glassy carbon electrode suggests that a specific interaction seems to occur between the glassy carbon surface and the aromatic ring of the pyridinium derivative. For all electrodes, an enhancement of current was observed in presence of CO2. However, NMR analyses of the solutions following electrolysis have not shown the formation of methanol or other possible by-products of the reduction of CO2 in the presence of both pyridinium derivative ions.
      PubDate: 2017-10-12T12:25:22.027244-05:
      DOI: 10.1002/cssc.201701745
       
  • Encapsulating Co2P@C Core-Shell Nanoparticles in Porous Carbon Sandwich: a
           Nitrogen and Phosphorus Dual-Doped PH-Universal Electrocatalysts for
           High-efficient Hydrogen Evolution
    • Authors: YuanYuan Yang; XiongYi Liang, Feng Li, ShuWen Li, XinZhe Li, Siu-Pang Ng, Chi-Man Lawrence Wu, Rong Li
      Abstract: A new, highly-efficient and pH-universal sandwich-architecture HER electrocatalysts, constructed by 0-dimensional N and P dual-doped core-shell Co2P@C nanoparticles embedded into a 3-dimensional porous carbon sandwich (Co2P@N,P-C/CG), was synthesized by a facile two-step method of hydrothermal carbonization (HTC) and pyrolysis. Owing to the synergistic effect of N, P-codoped Co2P@C core-shell and sandwich-nanostructural substrates, it increases the interfacial electron transfer rate and the number of active sites. Because of the presence of high surface area and large porous sizes, it improves the mass transfer dynamics. This nanohybrid shows remarkable electrocatalytic activity toward the HER in wide pH value, with good stability. The computational study and experiments reveal that the carbon atoms closed to N and P heteroatoms dopants on the shell of Co2P@N,P-C are the effective active sites for HER catalyst, and Co2P and N, P dopants synergistically optimize the binding free energy of H* on the active sites.
      PubDate: 2017-10-12T10:25:28.977874-05:
      DOI: 10.1002/cssc.201701705
       
  • Polymeric Redox-Active Electrodes for Sodium-Ion Batteries
    • Authors: Naiara Fernández; Paula Sánchez-Fontecoba, Elizabeth Castillo-Martínez, Javier Carretero-González, Teófilo Rojo, Michel Armand
      Abstract: Polymer binding agents are critical for the good performance of the electrodes of Na- and Li-ion batteries during cycling as they hold the electroactive material together to form a cohesive assembly because of their mechanical and chemical stability as well as adhesion to the current collector. New redox-active polymer binders that insert Na+ ions and show adhesion properties were synthesized by adding polyether amine blocks (Jeffamine) based on mixed propylene oxide and ethylene oxide blocks to p-phenylenediamine and terephthalaldehyde units to form electroactive Schiff-base groups along the macromolecule. The synthetic parameters and the electrochemical properties of these terpolymers as Na-ion negative electrodes in half cells were studied. Reversible capacities of 300 mAh g−1 (50 wt % conducting carbon) and 200 mAh g−1 (20 wt % conducting carbon) were achieved in powder and Cu-supported electrodes, respectively, for a polySchiff-polyether terpolymer synthesized by using a poly(ethylene oxide) block of 600 g mol−1 in place of one third of the aniline units. The new redox-active polymers were also used as a binding agent of another anode material (hard carbon), which led to an increase of the total capacity of the electrode compared to that prepared with other standard fluorinated polymer binders such as poly(vinylidene) fluoride.Binding agreement: A new redox-active polymer binder inserts Na+ ions and shows adhesive properties. This new material is synthesized by adding polyether amine groups onto mixed propylene oxide and ethylene oxide blocks to make p-phenylenediamine and terephthalaldehyde units and form electroactive Schiff-base groups along the macromolecule.
      PubDate: 2017-10-12T06:40:34.248134-05:
      DOI: 10.1002/cssc.201701471
       
  • Single-Atom Catalysts of Precious Metals for Electrochemical Reactions
    • Authors: Jiwhan Kim; Hee-Eun Kim, Hyunjoo Lee
      Abstract: Single-atom catalysts (SACs), in which metal atoms are dispersed on the support without forming nanoparticles, have been used for various heterogeneous reactions and most recently for electrochemical reactions. In this Minireview, recent examples of single-atom electrocatalysts used for the oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR), hydrogen evolution reaction (HER), formic acid oxidation reaction (FAOR), and methanol oxidation reaction (MOR) are introduced. Many density functional theory (DFT) simulations have predicted that SACs may be effective for CO2 reduction to methane or methanol production while suppressing H2 evolution, and those cases are introduced here as well. Single atoms, mainly Pt single atoms, have been deposited on TiN or TiC nanoparticles, defective graphene nanosheets, N-doped covalent triazine frameworks, graphitic carbon nitride, S-doped zeolite-templated carbon, and Sb-doped SnO2 surfaces. Scanning transmission electron microscopy, extended X-ray absorption fine structure measurement, and in situ infrared spectroscopy have been used to detect the single-atom structure and confirm the absence of nanoparticles. SACs have shown high mass activity, minimizing the use of precious metal, and unique selectivity distinct from nanoparticle catalysts owing to the absence of ensemble sites. Additional features that SACs should possess for effective electrochemical applications were also suggested.Down to the atom: Single-atom catalysts, in which metal atoms are dispersed on the support without forming nanoparticles, have recently been used for electrochemical reactions. In this Minireview, recent examples of single-atom electrocatalysts for reactions including oxygen reduction, hydrogen oxidation, hydrogen evolution, formic acid oxidation, and methanol oxidation are introduced.
      PubDate: 2017-10-10T04:30:36.459334-05:
      DOI: 10.1002/cssc.201701306
       
  • Nitrogen-Doped Carbon Nanotubes Derived from Metal-Organic Frameworks for
           Potassium-Ion Battery Anodes
    • Authors: Peixun Xiong; Xinxin Zhao, Yunhua Xu
      Abstract: To tackle the issue of the poor rate capability of graphite anodes for potassium-ion batteries (KIBs), nitrogen-doped carbon nanotubes (NCNTs) with an edge-open layer-alignment structure were synthesized using a simple and scalable approach of pyrolyzing cobalt-containing metal-organic frameworks. The unique structure enables a facile and fast intercalation of K ions. As anodes of KIBs, the NCNTs demonstrated a superior rate capability by a high capacity retention of 102 mA h g-1 at a high current density of 2000 mA g-1 and a good stability without obvious capacity loss over 500 cycles at 2000 mA g-1. Our findings would help to develop high performance anode materials for potassium-ion batteries as large-scale and low-cost energy storage systems.
      PubDate: 2017-10-10T00:50:22.203168-05:
      DOI: 10.1002/cssc.201701759
       
  • Catalytic Hydrogenation of Macroalgae-derived Alginic Acid into Sugar
           Alcohols
    • Authors: Chunghyeon Ban; Wonjin Jeon, Hee Chul Woo, Do Heui Kim
      Abstract: Alginic acid, a major constituent of macroalgae, was hydrogenated into sugar alcohols over carbon-supported noble metals for the first time. Mannitol and sorbitol were mainly produced via the catalytic hydrogenation of alginic acid, which consists of two epimeric uronic acids. The main reaction pathway is the consecutive hydrogenation of aldehyde- and carboxyl-end of alginic acid dimers followed by the cleavage of C-O-C linkage into monomeric units via hydrolysis. The highest yield of C6 sugar alcohols is 61% (sorbitol: 29%, mannitol: 28%, and galactitol: 4%). The low value of sorbitol to mannitol ratio differs to the case of cellulose hydrogenation due to the composition of alginic acid and isomerization between sugar alcohols under the catalytic system. Such a new and green route to produce sugar alcohols from alginic acid would provide opportunities to diversify biomass resources.
      PubDate: 2017-10-06T03:05:56.427648-05:
      DOI: 10.1002/cssc.201701860
       
  • Solid Aluminum Borohydrides as Perspective Hydrogen Stores
    • Authors: Iurii Dovgaliuk; Damir Safin, Nikolay Tumanov, Fabrice Morelle, Adel Moulai, Radovan Černý, Zbigniew Łodziana, Michel Devillers, Yaroslav Filinchuk
      Abstract: Metal borohydrides are intensively researched as high capacity hydrogen storage materials. Aluminum is a cheap, light and abundant element and Al3+ can be a template for reversible dehydrogenation. However, Al(BH4)3, containing 16.9 weight % of hydrogen, has a low boiling point, is explosive on air and has poor storage stability. We present a new family of mixed-cation borohydrides M[Al(BH4)4], all solid at ambient conditions. Their thermal decomposition properties show diverse behavior: Al(BH4)3 is released for M = Li+, Na+, while heavier derivatives evolve hydrogen and diborane. NH4[Al(BH4)4], containing protic and hydridic hydrogens, has the lowest decomposition temperature of 35 °C and yields Al(BH4)3∙NHBH and hydrogen. The decomposition temperatures, correlated with cations' ionic potential, show that M[Al(BH4)4] are in the most practical stability window. This family of solids with convenient and versatile properties puts aluminum borohydride chemistry in the mainstream of the hydrogen storage research, e.g. for the development of reactive hydride composites with an increased hydrogen content.
      PubDate: 2017-10-05T12:05:36.497016-05:
      DOI: 10.1002/cssc.201701629
       
  • Niobium Doped Lanthanum Strontium Ferrite as A Redox Stable and
           Sulfur-Tolerant Anode for Solid Oxide Fuel Cells
    • Authors: Zhe Lü; Jingwei Li, Bo Wei, Zhiqun Cao, Xing Yue, Yaxin Zhang
      Abstract: A novel Nb-doped lanthanum strontium ferrite perovskite oxide La0.8Sr0.2Fe0.9Nb0.1O3-δ (LSFNb) is evaluated as anode material of solid oxide fuel cell (SOFC). The effects of Nb partial substitution on the crystal structure, electrical conductivity and valence of Fe ions are studied. A good structural stability of LSFNb in severe reducing atmosphere at 800 °C is found, suggesting that high valent Nb can effectively promote the stability of lattice structure. The ratio of Fe2+ increases after Nb doping as confirmed by the results of XPS. The maximum power density of a thick Sc-stabilized zirconia (ScSZ) electrolyte supported single cell reached 241.6 mW·cm-2 at 800 °C using H2 as fuel. The cell exhibited excellent stability for continuously 100 h operation without detectable degeneration. SEM images clearly revealed the exsolutions on LSFNb surface after operation. Meanwhile, LSFNb particles agglomerated obviously during long-term stability test. Impedance spectra suggested that both LSFNb anode and (La0.75Sr0.25)0.95MnO3-δ (LSM)/ScSZ cathode exhibited an activation process during long-term test, through which the ability of charge transfer increases obviously. Meanwhile, low-frequency resistance (RL) mainly attributed by anode (80%) significantly increased, probably due to the agglomeration of LSFNb particles. The LSFNb anode exhibits excellent anti-sulfuring poisoning ability and redox stability. These results demonstrate that LSFNb is a promising anode material for SOFC.
      PubDate: 2017-10-04T08:15:30.791593-05:
      DOI: 10.1002/cssc.201701638
       
  • Designing CdS mesoporous networks on MOF derived Co-C@Co9S8 double-shelled
           nanocages as a redox-mediator-free Z-scheme photocatalyst with superior
           photocatalytic efficiency
    • Authors: D. Amaranatha Reddy; Hanbit Park, Madhusudana Gopannagari, Eun Hwa Kim, Seunghee Lee, D. Praveen Kumar, Tae Kyu Kim
      Abstract: Designing porous nanostructures with unprecedented functions and an effective ability to harvest the maximum energy region of the solar spectrum and suppress the charge-carrier recombination rate is offering promising potential for sustainable energy production. Herein, we report a new, highly active, noble-metal-free, and redox-mediator-free Z-scheme photocatalyst, CdS/Co-C@Co9S8, for H2 production through water splitting under solar irradiation. The designed photocatalytic system contains open 3D CdS mesopores as a light absorber for wider solar light harvesting. Metal-organic-framework-derived cobalt nanocrystal-embedded few-layered carbon@Co9S8 double-shelled nanocages were used as a co-semiconductor to hamper the photo charge-carrier recombination by accelerating the photogenerated electrons and holes from the other semiconductor. The optimized catalyst shows a H2 evolution rate of 26.69 mmol·g-1·h-1 under simulated solar irradiation, which is 46 times higher than that of as-synthesized CdS mesoporous nanostructures. The apparent quantum yield reached 7.82 % at λ=425 nm in 5 h. The spectacular photocatalytic activity of CdS/Co@C-Co9S8 reflects the favorable suppression of the charge-carrier recombination rate, as determined by photoluminescence, photocurrent, and impedance analyses. We believe that the findings reported here may inspire the design of novel noble-metal-free porous nanohybrids for sustainable H2 production.
      PubDate: 2017-10-03T07:35:47.447998-05:
      DOI: 10.1002/cssc.201701643
       
  • Flower-like nickel phosphide microballs assembled by nanoplates with
           exposed high energy (001) facet: efficient electrocatalyst for hydrogen
           evolution reaction
    • Authors: Honglei Wang; Ying Xie, Hongshuai Cao, Yanchao Li, Lin Li, Zhikun Xu, Xiuwen Wang, Ni Xiong, Kai Pan
      Abstract: Fabrication of low-cost and earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) over a broad pH range is attracting the researcher attention. In this work, a facile precursor route is developed to synthesize flower-like nickel phosphide microballs with a diameter of ca. 12 μm. With controllable phosphorization temperature, the flower-like nickel phosphide microballs with different crystalline structures (Ni5P4 and Ni2P) could be easily obtained. This hierarchical structure possessed two merits for enhanced HER, the fast vectorial electron transfer path along the building block nanoplates and enhanced inherent catalytic activity of each active site for high energy (001) facets. So, flower-like Ni5P4 microballs displayed an excellent electrocatalytic activity for HER with a low overpotential (η) of 35.4 mV to reach current densities of 10 mA cm-2, and a smaller Tafel slope of 48 mV·dec-1 in acid solution. In addition, it showed an excellent activity in 1 M KOH with a η of 47 mV at 10 mA cm-2. The density functional theory indicated that the free energy of hydrogen adsorbed on Ni site of Ni5P4 was 0.152 eV, which was smaller than that of Ni site of Ni2P (0.182 eV). So, flower-like Ni5P4 microballs possessed better HER activity than Ni2P, which is consistent with our HER data. This hierarchical structure with exposed high energy (001) facets paves a new way to design and synthesize a low-cost and high-performance catalyst for HER.
      PubDate: 2017-10-02T21:26:10.787902-05:
      DOI: 10.1002/cssc.201701647
       
  • The enhanced photocatalytic hydrogen evolution of NiCoP/g-C3N4 with the
           improved separation efficiency and charge transfer efficiency
    • Authors: Lingling Bi; Xupeng Gao, Lijing Zhang, Dejun Wang, Xiaoxin Zou, Tengfeng Xie
      Abstract: NiCoP has caused wide attention in the field of electrocatalysis, while there is little concern on photocatalysis study and its photocatalytic mechanism. Herein we reported a simple one-pot synthesis method of NiCoP/g-C3N4 as highly efficient photocatalyst for hydrogen production from water for the first time. Remarkably, the excellent photocatalytic activity is obtained for the 50 mg NiCoP/g-C3N4 (1643 molg-1h-1), which is 21 times higher than that of bare g-C3N4. The excellent performance is due to the synergistic effect of the improved separation efficiency and the effective charge transfer efficiency. The photogenerated charge behavior is characterized by the surface photovoltage, the transient photovoltage and the photoluminescence spectroscopy. The photogenerated charge transport property is researched by the electrochemical impedance spectroscopy and polarization curve. Moreover, the effective charge transfer efficiency was measured according to the mimetic apparent quantum yield. Specifically, the novel SPV and TPV measurements that added 10 vol% triethanolamine-water solution into the testing system were measured to simulate the real atmosphere for photocatalytic reaction, which can directly provide the actual photogenerated charge transfer process. This work may provide an efficient theoretical basis to design transition metal phosphide cocatalyst modified photocatalysts. Finally, the possible photocatalytic mechanism was proposed and discussed in detail.
      PubDate: 2017-10-02T08:20:20.452586-05:
      DOI: 10.1002/cssc.201701574
       
  • Low-polarization lithium oxygen battery using
           N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium
           bis(trifluoromethanesulphonyl) imide (DEMETFSI) ionic liquid electrolyte
    • Authors: Ulderico Ulissi; Giuseppe Antonio Elia, Sangsik Jeong, Franziska Mueller, Jakub Reiter, Nikolaos Tsiouvaras, Yang-Kook Sun, Bruno Scrosati, Stefano Passerini, Jusef Hassoun
      Abstract: The room temperature molten salt mixture of N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis(trifluoromethanesulfonyl) imide (DEMETFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is herein reported as electrolyte for application in lithium oxygen batteries. The DEMETFSI-LITFSI solution is studied in terms of ionic conductivity, viscosity, electrochemical stability and compatibility with lithium metal at 30°C, 40°C and 60°C. The electrolyte shows suitable properties for application in lithium oxygen battery, allowing a reversible, low-polarization discharge-charge performance with a capacity of about 13 Ah per gram of carbon in the positive electrode and coulombic efficiency approaching 100%. The reversibility of the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) is demonstrated by ex situ XRD and SEM studies. Furthermore, the study of the cycling behavior of the lithium oxygen cell using the DEMETFSI-LITFSI electrolyte at increasing temperatures (from 30°C to 60°C) evidences enhanced energy efficiency together with morphology changes of the deposit. In addition, the use of carbon-coated Zn0.9Fe0.1O (TMO-C) lithium-conversion anode in an IL-based Li-ion oxygen configuration is preliminarily demonstrated.
      PubDate: 2017-09-29T08:42:41.400739-05:
      DOI: 10.1002/cssc.201701696
       
  • Exploring the reaction pathways of bio-glycerol hydro-deoxygenation to
           propene over Molybdena-based catalysts
    • Authors: Vasiliki Zacharopoulou; Efterpi Vasiliadou, Angeliki A Lemonidou
      Abstract: One-step glycerol reaction with hydrogen, selectively forming propene, is a novel and particularly challenging catalytic pathway that has not yet been thoroughly explored in the open literature. Molybdena-based catalysts are active and selective to C-O bond scission; propene is the only product in the gas phase, under the standard reaction conditions, impeding further hydrogenation to propane. Within this context, this work focuses on exploration of the reaction pathways and the investigation of various parameters, affecting the catalytic performance, such as the role of hydrogen on the product distribution and the effect of the catalyst pretreatment step. Under hydrogen atmosphere, propene is primarily produced via 2-propenol formation, while under inert atmosphere propanal and glycerol dissociation products are mainly formed. Reaction most likely proceeds through a reverse Mars van Krevelen mechanism, as the partially reduced Mo species drive the reaction to the formation of the desired product.
      PubDate: 2017-09-28T10:30:44.058516-05:
      DOI: 10.1002/cssc.201701605
       
  • Mesoporous Carbon Nanospheres Encapsulated Ultrasmall Ir Clusters as
           Highly Selective Nanocatalysts for (Bio-)Alcohols Methylation Using
           Methanol as Sustainable C1 Feedstock
    • Authors: Qiang Liu; Guoqiang Xu, Zhendong Wang, Xiaoran Liu, Xicheng Wang, Linlin Dong, Xindong Mu, Huizhou Liu
      Abstract: C-H methylation is an attractive chemical transformation for C-C bonds construction in organic chemistry, yet efficient methylation of readily available (bio-)alcohols in water using methanol as sustainable C1 feedstock is limited. Herein, yolk-shell-structured mesoporous carbon nanospheres encapsulated Ir nanocatalysts (Ir@YSMCNs) have been synthesized for this transformation. Monodispersed Ir clusters (ca. 1.0 nm) were in situ encapsulated and spatially isolated within YSMCNs by a silica-assisted sol-gel emulsion strategy. A selection of (bio-)alcohols (19 examples) was selectively methylated in aqueous phase with good-to-high yields over the developed Ir@YSMCNs. The improved catalytic efficiencies in terms of activity, selectivity together with the good stability and recyclability were contributable to the ultrasmall Ir clusters with oxidation chemical state as a consequence of the confinement effect of YSMCNs with interconnected nanostructures.
      PubDate: 2017-09-25T23:15:27.000918-05:
      DOI: 10.1002/cssc.201701607
       
  • Interface Manipulation Improving Plasmon-Coupled Photoelectrochemical
           Water Splitting on α-Fe2O3 Photoanodes
    • Authors: Zhe Xu; Zhongwen Fan, Zhan Shi, Mengyu Li, Jianyong Feng, Lang Pei, Chenguang Zhou, Junkang Zhou, Lingxia Yang, Wenchao Li, Guangzhou Xu, Shicheng Yan, Zhigang Zou
      Abstract: Plasmon resonance effect of metal nanoparticles (NPs) offers a promising route to improve the solar energy conversion efficiency of semiconductors. Here, we found that the hot electrons generated by plasmon resonance effect of Au NPs tend to inject into the surface states instead of the conduction band of Fe2O3 photoanodes, then the severe surface recombination occurs. Such an electron transfer process seems to be independent on external applied potentials, but is sensitive to metal-semiconductor interface properties. Passivating the surface states of Fe2O3 by a non-catalytic Al2O3 layer can construct an effective resonant energy transfer interface between Ti-doped Fe2O3 (Ti-Fe2O3) and Au NPs. In such a Ti-Fe2O3/Al2O3/Au electrode configuration, the enhanced photoelectrochemical water splitting performance can be attributed to the following two factors: (1) in non-light-response wavelength range of Au NPs, both relaxing Fermi pinning effect by Al2O3 passivation layer and higher work function of Au enlarged band bending, thus promoting the charge separation. (2) In light-response wavelength range of Au NPs, the effective resonant energy transfer contributes to the light harvesting and conversion. The interface manipulation proposed in our study may provide a new route to design efficient plasmonic PEC devices for energy conversion
      PubDate: 2017-09-21T21:20:51.705638-05:
      DOI: 10.1002/cssc.201701679
       
  • Preparation of Cobalt-Based Electrodes by Physical Vapor Deposition on
           Various Nonconductive Substrates for Electrocatalytic Water Oxidation
    • Authors: Yizhen Wu; Le Wang, Mingxing Chen, Zhaoxia Jin, Wei Zhang, Rui Cao
      Abstract: Artificial photosynthesis requires efficient anodic electrode materials for water oxidation. We herein report the facial preparation of Co metal thin films through physical vapor deposition (PVD) on various nonconductive substrates, including regular and quartz glass, mica sheet, polyimide, and polyethylene terephthalate (PET). Subsequent surface electrochemical modification using cyclic voltammetry (CV) makes these films active for electrocatalytic water oxidation by reaching a current density of 10 mA cm−2 at a low overpotential of 330 mV in 1.0 M KOH solution. These electrodes are robust with unchanged activity in prolonged chronopotentiometry measurements. This work is thus significant to show that the combination of PVD and CV is very valuable and convenient to fabricate active electrodes using various nonconductive substrates, particularly, flexible polyimide and PET substrates. This efficient, safe and convenient way can be potentially expanded to many other electrochemical applications.
      PubDate: 2017-09-21T09:20:43.228645-05:
      DOI: 10.1002/cssc.201701576
       
  • Reactive electrophilic OI--species evidenced in high-performance
           Ir-oxohydroxide water oxidation electrocatalysts
    • Authors: Cyriac Massué; Verena Pfeifer, Maurice Van Gastel, Johannes Noack, Gerardo Algara-Siller, Sebastien Cap, Robert Schlögl
      Abstract: Although quasi-amorphous Ir-oxohydroxides haverepeatedly been identified as superior oxygen evolution reaction(OER) electrocatalysts, an exact description of the performance relevantspecies has so far remained a challenge. In this context, wereport on the characterization of hydrothermally prepared IrIII/IV oxohydroxides exhibiting exceptional OER-performance. It was foundthat holes in the O2p states of IrIII/IV-oxohydroxides result in reactiveOI--species identified by characteristic NEXAFS-features. Aprototypical titration reaction based on CO as a probe molecule showsthat these OI--species are highly susceptible to nucleophilic attack atroom temperature. Similarly to pre-activated oxygen involved in thebiological OER in Photosystem II, the electrophilic OI--speciesevidenced in IrIII/IV-oxohydroxides are suggested to be precursors tospecies involved in the O-O bond formation during electrocatalyticOER. CO-titration also highlights a link between OER-performanceand the surface/sub-surface mobility of OI--species. The superiorelectrocatalytic properties of IrIII/IV-oxohydroxides are thus explainedby their ability to accommodate pre-activated electrophilic OI--speciesable to migrate within the lattice.
      PubDate: 2017-09-21T03:21:02.885574-05:
      DOI: 10.1002/cssc.201701291
       
  • Imidazolium Ions with an Alcohol Substituent for Enhanced Electrocatalytic
           Reduction of CO2
    • Authors: Xianbo Jin; Lin Zhang, Nian Wu, Jichen Zhang, Yang Hu, Zhiyong Wang, Lin Zhuang
      Abstract: Electrochemical reduction of CO2 to CO is attractive for carbon dioxide reduction, energy regeneration and storage. Imidazolium Ionic liquids (IMILs) are promising electrolyte catalysts for this important reaction. Herein we report functionalizing the imidazolium ion with a propanol substituent at the N site can significantly enhance the catalytic activity of IMILs, causing a positive shift of the onset potential for the CO2 reduction by about 90 mV in an acetonitrile electrolyte. Theoretical calculation indicated that the propanol hydroxyl could bridge a local hydrogen bonding chain as shortcut for proton transfer, leading to a dramatic decrease of the activation barrier for the IMIL-catalytic reduction of CO2.
      PubDate: 2017-09-20T04:20:22.109872-05:
      DOI: 10.1002/cssc.201701673
       
  • NIR Absorbing Metal-Free Organic, Porphyrin, and Phthalocyanine Dyes for
           Panchromatic DSCs
    • Authors: Phillip Brogdon; Hammad Cheema, Jared Heath Delcamp
      Abstract: Dye-sensitized solar cells (DSCs) are a promising source of renewable energy. However, power conversion efficiency (PCE) of devices has been limited largely by the difficulty of producing electricity using photons from the near-infrared (NIR) spectral region. Metal-free organic sensitizers frequently employ strong electron donating or withdrawing moieties to tune the optical band gap to allow the absorption of lower energy wavelengths in charge transfer systems while porphyrins and phthalocyanines use substituents to shift the Soret and Q bands toward lower energy absorption. Very few devices employing precious metal free dyes have been able to achieve panchromatic, NIR photon conversion for electricity generation at wavelengths>750 nm despite a tremendous number of sensitizers published over last 25 years. This minireview seeks to compile a summary of these sensitizers to encourage assimilation, analysis and development of efficient future NIR sensitizers. Herein, we discuss common synthetic strategies, optical properties and electronic properties of the most successful panchromatic organic sensitizers in this regard.
      PubDate: 2017-09-19T13:40:32.723807-05:
      DOI: 10.1002/cssc.201701441
       
  • A Strategy for Simultaneous Synthesis of Methallyl Alcohol and Diethyl
           Acetal with Sn-β
    • Authors: Wenda Hu; Yan Wan, Lili Zhu, Xiaojie Cheng, Shaolong Wan, Jingdong Lin, Yong Wang
      Abstract: Herein we report a strategy to simultaneously produce two important chemicals namely Methallyl alcohol (Mol) and diethyl acetal (Dal) from methacrolein (Mal) in ethanol solvent at low temperature with the use of Beta zeolites modified by tin (Sn-β catalysts). All Sn-β catalysts were prepared by the solid-state ion-exchange (SSIE) method, wherein the calcination step was conducted in different gas atmospheres. The one pre-calcined in Ar (Sn-β-Ar) diminishes the number of extra-framework Sn species and instead enables more Sn species exchanged into the framework as isolated tetrahedral Sn (IV), thus enhancing the catalytic activity of Meerwein-Ponndorf-Verley (MPV) reaction. The sodium-exchanged Sn-β-Ar, with the weak Brønsted acid site further diminished, leads to an even better result to Mol, thanks to the restriction of those side reactions such as acetalization, addition and etherification. Under optimized catalyst and reaction condition, the yield of Mol and Dal could reach about 90% and 96%, respectively. The possible reaction pathway, along with the complex network of side products, was proposed after a detailed investigation through the use of different substrates as the reactants. The findings of Sn-β fine-tuned through different treatment in this work, are of great significance toward understanding and manipulating the complex reaction between ɑ, β-unsaturated aldehydes and primary alcohols.
      PubDate: 2017-09-19T07:40:44.303221-05:
      DOI: 10.1002/cssc.201701435
       
  • Anion Exchange Membranes for Alkaline Fuel Cell Applications: The Effects
           of Cations
    • Authors: Zhe Sun; Bencai Lin, Feng Yan
      Abstract: Alkaline anion exchange membrane fuel cells (AEMFCs) are attracting great attention, because of their potential use of non-precious electrocatalysts. Anion exchange membrane (AEM) is one of the key components of AEMFCs. An ideal AEM should possess high hydroxide conductivity and sufficient long-term durability at elevated temperatures in high pH solutions. This review provides recent progresses of alkaline stability behavior of cations (including quaternary ammonium, imidazolium, guanidinium, pyridinium, tertiary sulfonium, phosphonium, benzimidazolium and pyrrolidinium) and their analogous AEMs, which have been investigated by both experimental studies and theoretical calculations. Effects, including conjugated effect, steric hindrance effect, σ−π hyperconjugative effect and electron effect on the alkaline stability of cations and their analogous AEMs have been discussed. The attempt of this article is to give an overview of some key factors, for future design of novel cations, and their analogous AEMs with high alkaline stability.
      PubDate: 2017-09-18T10:40:40.577073-05:
      DOI: 10.1002/cssc.201701600
       
  • Stupendous Role of Co-sensitizers in Dye Sensitized Solar Cells
    • Authors: Lingamallu Giribabu; Vamsi Krishna Narra, Venkata Suman Krishna Jonnadula, Mrinalini Madoori, Prasanthkumar Seelam
      Abstract: Co-sensitization in dye sensitized solar cells (DSSCs) received significant attention for improving the efficiency and stability of renewable energy resources. In this context, ruthenium metal and porphyrin dyes based DSSCs achieved increment in power conversion efficiency (PCE) from 8 - 11% to 11-14% after addition of additives, co-adsorbents and co-sensitizers by reducing the aggregation and charge recombination. Among the three supporting materials, co-sensitizers played major role to enhance the performance and stability of DSSCs which assist in commercialization. In this review, we highlighted the importance of co-sensitizers in photovoltaic performance of ruthenium metal and porphyrin dye based solar cells. Consequently, co-sensitizers are rather important to modulate the PCE of DSSCs and find realistic future practical applications.
      PubDate: 2017-09-16T04:20:22.917607-05:
      DOI: 10.1002/cssc.201701224
       
  • Chemoselective and catalyst-free O-borylation of silanols: a facile access
           to borasiloxanes
    • Authors: Krzysztof Kuciński; Grzegorz Hreczycho
      Abstract: This paper demonstrates, for the first time, a highly chemoselective synthesis of various borasiloxanes from hydroboranes and silanols which was achieved through a catalyst-free dehydrogenative coupling at room temperature. This green protocol, which uses easily accessible reagents, allows for the obtaining of borasiloxanes under air atmosphere and solvent-free conditions.
      PubDate: 2017-09-15T12:21:01.830659-05:
      DOI: 10.1002/cssc.201701648
       
  • Green and sustainable route to carbohydrate vinyl ethers for accessing
           bio-inspired materials with a unique microspherical morphology
    • Authors: Konstantin Rodygin; Irina Werner, Valentine P. Ananikov
      Abstract: Synthesizing chemicals and materials based on renewable sources is one of the main tasks of modern science. Carbohydrates represent excellent renewable natural raw materials, that are eco-friendly, inexpensive and biologically compatible. Herein, we developed a green vinylation procedure for carbohydrates using readily available calcium carbide. Various carbohydrates were utilized as starting materials resulting in mono-, di- and tetra-vinyl ethers in high to excellent yields (81-92 %). The synthesized bio-based vinyl ethers were utilized as monomers in free radical and cationic polymerizations. A unique combination of smooth surface and intrinsic microcompartments was achieved in the synthesized materials. Two types of bio-based materials were prepared involving microspheres and "Swiss cheese" polymers. Scanning electron microscopy with built-in ion beam cutting was applied to reveal the spatial hierarchical structures in three-dimensional space.
      PubDate: 2017-09-12T05:21:44.227869-05:
      DOI: 10.1002/cssc.201701489
       
  • Rational Development of Neutral Aqueous Electrolytes for Zinc-Air
           Batteries
    • Authors: Simon Clark; Arnulf Latz, Birger Horstmann
      Abstract: Neutral aqueous electrolytes have been shown to extend both the calendar-life and cycling stability of secondary zinc-air batteries (ZABs). Despite this promise, there are currently no modeling studies investigating the performance of neutral ZABs. Traditional continuum models are numerically insufficient to simulate the dynamic behavior of these complex systems, due to the rapid, orders-of-magnitude concentration shifts that occur. In this work, we present a novel framework for modeling the cell-level performance of pH-buffered aqueous electrolytes. We apply our model to conduct the first continuum-scale simulation of secondary ZABs with aqueous ZnCl2-NH4Cl electrolytes. We first use our model to interpret the results of two recent experimental studies of neutral ZABs, and show that the stability of the pH is a significant factor in cell performance. We then optimize the composition of the electrolyte and the design of the cell considering factors including pH stability, final discharge product and overall energy density. Our simulations predict that the effectiveness of the pH buffer is limited by slow mass transport and that chlorine-containing solids may precipitate in addition to ZnO.
      PubDate: 2017-09-12T05:21:19.927613-05:
      DOI: 10.1002/cssc.201701468
       
  • Catalytic upgrading of ethanol to n-butanol: A progress in catalyst
           development
    • Authors: Xianyuan Wu; Geqian Fang, Yuqin Tong, Dahao Jiang, Zhe Liang, Wenhua Leng, Liu Liu, Pengxiang Tu, Hongjing Wang, Jun Ni, Xiaonian Li
      Abstract: In view that n-butanol as fuel additive has more advantageous physico-chemical properties compared to ethanol, ethanol valorization to n-butanol via homogeneous or heterogeneous catalysis has received great attention over the last decades both in the scientific and industrial fields. This paper reviewed the recent progress in catalyst development for upgrading ethanol to n-butanol, which involves homogeneous catalysts such as Iridium and Ruthenium complexes catalysts and heterogeneous catalysts mainly including metal oxides, hydroxyapatite (HAP) and especially supported metal catalysts. The structure-performance relationship of catalysts and underlying reaction mechanism were critically examined. Future research directions on the catalyst design and improvement were also proposed.
      PubDate: 2017-09-12T03:21:19.653865-05:
      DOI: 10.1002/cssc.201701590
       
  • In-Situ Formed Hierarchical Metal-Organic Flexible Cathode for High-Energy
           Sodium-Ion Batteries
    • Authors: Ying Huang; Chun Fang, Rui Zeng, Yaojun Liu, Wang Zhang, Yanjie Wang, Qingju Liu, Yunhui Huang
      Abstract: Metal-organic compounds are a family of electrode materials with structural diversity and excellent thermal stability for rechargeable batteries. Here, we fabricate a hierarchical nanocomposite with metal-organic cuprous tetracyanoquino- dimethane (CuTCNQ) in three-dimensional (3D) conductive carbon nanofibers (CNFs) network by in-situ growth, and evaluate it as flexible cathode for sodium-ion batteries (SIBs). CuTCNQ in such flexible composite electrode is able to exhibit a superhigh capacity of 252 mAh g-1 at 0.1 C and highly reversible stability for 1200 cycles within the voltage range of 2.5 - 4.1 V (vs. Na+/Na). A high specific energy of 762 Wh kg-1 is obtained with high average potential of 3.2 V (vs. Na+/Na). The in-situ formed electroactive metal-organic composites with tailored nanoarchitecture provide a promising alternative choice for high-performance cathode materials in sodium-ion batteries with high energy.
      PubDate: 2017-09-10T21:25:46.040595-05:
      DOI: 10.1002/cssc.201701484
       
  • Rational Design of Sulfur-Doped Copper Catalysts for the Selective
           Electroreduction of Carbon Dioxide to Formate
    • Authors: Yun Huang; Yilin Deng, Albertus Denny Handoko, Gregory K L Goh, Boon Siang Yeo
      Abstract: The selective electroreduction of CO2 to formate (or formic acid) is currently of great interest in the field of renewable energy utilization. In this work, we designed a sulfur-doped Cu2O-derived Cu catalyst, and showed that the presence of sulfur could significantly tune the selectivity of Cu from producing a myriad of CO2 reduction products to almost exclusively formate. Sulfur is doped into the Cu catalysts by dipping the Cu substrates into ammonium polysulfide solutions. Catalyst films with the highest sulfur content of 2.7 atom% showed the largest formate current density (jHCOO-) of -13.9 mA/cm2 at -0.9 V vs. RHE, which is ~46 times larger than that previously reported on Cu(110) surfaces. At -0.8 V vs. RHE, the Faradaic efficiency of formate was maintained at ~75% for 12 h of continuous electrolysis. By analyzing how the jHCOO- and jH2 of the catalysts evolved with different sulfur content, we show that sulfur doping efficaciously increases formate production, while suppressing the hydrogen evolution reaction. Ag-S and Cu-Se catalysts did not exhibit any significant enhancement towards the reduction of CO2 to formate. This demonstrates clearly that sulfur and copper acted synergistically to promote the selective formation of formate. A hypothesis of the role of sulfur is proposed and discussed.
      PubDate: 2017-09-07T09:21:31.786827-05:
      DOI: 10.1002/cssc.201701314
       
  • Anatase-TiO2 as low-cost and sustainable buffering filler for nanosize
           Silicon anodes in Lithium-ion batteries
    • Authors: Fabio Maroni; Gilberto Carbonari, Fausto Croce, Roberto Tossici, Francesco Nobili
      Abstract: The design of effective supporting matrices to efficiently cycle Si nanoparticles is often difficult to be achieved and requires complex preparation strategies. In this work, we present a simple synthesis of low-cost and environmentally benign Anatase-TiO2 nanoparticles as buffering filler for Si nanoparticles (Si@TiO2). Average anatase crystallite size is estimated in 5 nm. A complete structural, morphological and electrochemical characterization is performed. Electrochemical test results show very good specific capacity values around up to 1000 mAhg-1 and cycling at several specific currents, ranging from 500 mAg-1 to 2000 mAg-1, demonstrating a very good tolerance to high cycling rates. Post-mortem morphological analysis shows very good electrode integrity after 100 cycles at 500 mAg-1 specific current.
      PubDate: 2017-09-07T08:20:45.708226-05:
      DOI: 10.1002/cssc.201701431
       
  • Co9S8/Co as a High Performance Anode for Sodium Ion Batteries with a
           Preferred Ether-based Electrolyte
    • Authors: Yingying Zhao; Qiang Pang, Yingjin Wei, Luyao Wei, Yanming Ju, Bo Zou, Yu Gao, Gang Chen
      Abstract: Co9S8 has been regarded as a desirable anode material for sodium ion batteries because of its high theoretical capacity. In this study, a Co9S8 anode material containing 5.5 wt% Co (Co9S8/Co) was prepared by a solid-state reaction. The material's electrochemical properties were studied with carbonate-based and ether-based electrolytes (the latter, EBE), which showed that the material had a longer cycling life and better rate capability in the EBE. This excellent electrochemical performance was attributed to the low apparent activation energy and the low over-potential for Na deposition in the ether based electrolyte, which improved the electrode kinetic properties. Also, EBE suppressed side reactions of the electrode and electrolyte, which avoided the formation of a solid electrolyte interphase film.
      PubDate: 2017-09-05T07:24:27.258399-05:
      DOI: 10.1002/cssc.201701334
       
  • Facile Spray Pyrolysis Synthesis of Yolk-shell Earth-abundant Elemental
           NiFe-based Nanohybrid Electrocatalysts for Full Water Splitting
    • Authors: Zhenhai Wen; Hao Li, Suqin Ci, Mengtian Zhang, Junxiang Chen, Keyuan Lai
      Abstract: It is critical while remains a daunting challenge in the development of high-activity electrocatalysts for water splitting that comprise only inexpensive, earth-abundant elements. In this work, the preparation of yolk-shell Ni3Fe/Ni3FeN was developed by a possible scale-up method using spray pyrolysis technique. The yolk-shell Ni3Fe/Ni3FeN presents excellent catalytic activity for OER and HER with overpotentials of 268 mV and 166 mV at 10 mA cm-2, respectively, and bears a prominent electrochemical durability. The overall water splitting on the electrolyzer with yolk-shell Ni3Fe/Ni3FeN as cathode and anode only requires a cell voltage of 1.62 V to reach current density of 10 mA cm-2. The present research not only proposes a new route in synthesizing advanced functional electrocatalysts for overall water splitting but also shed light on its potential commercial application.
      PubDate: 2017-08-28T09:16:37.643301-05:
      DOI: 10.1002/cssc.201701521
       
  • Angelica Lactones: from Biomass-Derived Platform Chemicals to Value-Added
           Products
    • Authors: Arlene Correa; Carolina G. S. Lima, Júlia Monteiro, Thiago Melo Lima, Marcio Webber Paixão
      Abstract: The upgrading of biomass-derived compounds has arisen in recent years as a very promising research field in both academia and industry. In this sense, a lot of new processes and products have been developed, often involving levulinic acid as a starting material or intermediate. In the last few years, though, other scaffolds have been receiving growing attention, in special, angelica lactones. Considering these facts and the emergent applications of said molecules, in this review we will discuss their preparation and applications - the use of these frameworks as starting materials in organic synthesis to produce potential bioactive compounds will be covered, as well as their arising use as the foundation to highly regarded compounds such as liquid alkanes with prospective use as fuels and polymers.
      PubDate: 2017-08-21T10:00:39.20312-05:0
      DOI: 10.1002/cssc.201701469
       
  • Heteroatom-doped Carbon Spheres from Hierarchical Hollow Covalent Organic
           Framework Precursors for Metal-Free Catalysis
    • Authors: Liuyi Li; Lu Li, Caiyan Cui, Hongjun Fan, Ruihu Wang
      Abstract: Covalent organic frameworks (COFs) with hollow structures hold great promise for developing new types of functional materials. Herein, we report a hollow spherical COF with a hierarchical shell, which serves as an effective precursor of B,N-codoped hierarchical hollow carbon spheres. Benefiting from the synergistic effects of hierarchical porosity, high surface area, and B,N-codoping, the as-synthesized carbon spheres show prospective utility as metal-free catalysts in nitroarene reduction. A mechanistic hypothesis is proposed based on theoretical and experimental studies. Boron atoms situated meta to pyridinic N atoms are identified to be the main catalytic active sites. The anti-aromaticity originating from the codoping of B and pyridinic N atoms, not charge distribution and deformation energy, is confirmed to play a pivotal role in the catalytic reaction.COF drops: Hierarchical hollow covalent organic frameworks (H-COFs) have been prepared and used as a precursor for the fabrication of heteroatom-doped porous carbons. Originating from of hierarchical porosity and crystallinity in H-COF, the as-synthesized carbon materials show promising performances in metal-free reduction of nitroarenes.
      PubDate: 2017-08-11T05:50:26.622262-05:
      DOI: 10.1002/cssc.201700979
       
  • Carbon Dioxide Capture by Aqueous Ionic Liquid Solutions
    • Authors: Nathalia M. Simon; Marcileia Zanatta, Francisco P. dos Santos, Marta C. Corvo, Eurico J. Cabrita, Jairton Dupont
      Abstract: Confined water in aqueous solutions of imidazolium-based ionic liquids (ILs) associated with acetate and imidazolate anions react reversibly with CO2 to yield bicarbonate. Three types of CO2 sorption in these “IL aqueous solutions” were observed: physical, CO2-imidazolium adduct generation, and bicarbonate formation (up to 1.9 molbicarbonate mol−1 of IL), resulting in a 10:1 (molar ratio) total absorption of CO2 relative to imidazolate anions in the presence of water 1:1000 (IL/water). These sorption values are higher than the classical alkanol amines or even alkaline aqueous solutions under similar experimental conditions.Trapped, but active: Aqueous solutions of ionic liquids (IL) with basic anions are employed for CO2 capture, resulting in higher values of sorption. The success of these experiments can be attributed to the occurrence of physical and chemical sorption, mainly owing to bicarbonate formation. Our detailed study shows that bicarbonate species are a result of the reversible reaction between water molecules trapped in the IL activated by the contact ion pair and CO2.
      PubDate: 2017-08-09T03:40:47.823848-05:
      DOI: 10.1002/cssc.201701044
       
  • Influence of the Water Phase State on the Thermodynamics of Aqueous-Phase
           Reforming for Hydrogen Production
    • Authors: Renée M. Ripken; Jan Meuldijk, Johannes G. E. Gardeniers, Séverine Le Gac
      Abstract: Hydrogen is a promising renewable energy source that can be produced from biomass using aqueous-phase reforming (APR). Here, using data obtained from AspenPlus and the literature, we evaluated the phase state, temperature-dependent enthalpy, and Gibbs free energy for the APR of small biomass model substrates. Phase equilibrium studies reveal that, under typical APR reaction conditions, the reaction mixture is in the liquid phase. Therefore, we show for the first time that the water-gas shift reaction (WGSR), which is the second main reaction of APR, must be modeled in the liquid phase, resulting in an endothermic instead of an exothermic enthalpy of reaction. A significant implication of this finding is that, although APR has been introduced as more energy saving than conventional reforming methods, the WGSR in APR has a comparable energy demand to the WGSR in steam reforming (SR).The reaction thermodynamics was evaluated to investigate the aqueous-phase reforming (APR) for hydrogen production from biomass. APR has a similar energy demand as steam reforming when neglecting the heat of evaporation of water as a solvent. Based on these results, the phase of the reactants would determine whether the water-gas shift reaction (WGSR) is a two-phase reaction or a three-phase reaction at the gas–liquid–solid interface.
      PubDate: 2017-08-09T01:50:46.007913-05:
      DOI: 10.1002/cssc.201700189
       
  • Preparation of Layered-Spinel Microsphere/Reduced Graphene Oxide Cathode
           Materials for Ultrafast Charge–Discharge Lithium-Ion Batteries
    • Authors: Dong Luo; Shaohua Fang, Li Yang, Shin-ichi Hirano
      Abstract: Although Li-rich layered oxides (LLOs) have the highest capacity of any cathodes used, the rate capability of LLOs falls short of meeting the requirements of electric vehicles and smart grids. Herein, a layered-spinel microsphere/reduced graphene oxide heterostructured cathode (LS@rGO) is prepared in situ. This cathode is composed of a spinel phase, two layered structures, and a small amount of reduced graphene oxide (1.08 wt % of carbon). The assembly delivers a considerable charge capacity (145 mA h g−1) at an ultrahigh charge– discharge rate of 60 C (12 A g−1). The rate capability of LS@rGO is influenced by the introduced spinel phase and rGO. X-ray absorption and X-ray photoelectron spectroscopy data indicate that Cr ions move from octahedral lattice sites to tetrahedral lattice sites, and that Mn ions do not participate in the oxidation reaction during the initial charge process.Fidget spinels: layered-spinel microspheres are prepared on reduced graphene oxide in situ, forming cathode materials for Li-ion batteries. They deliver a considerable capacity of 145 mA h g−1 at an ultrahigh charge– discharge rate of 60 C (12 A g−1).
      PubDate: 2017-08-09T01:45:27.292152-05:
      DOI: 10.1002/cssc.201701207
       
  • Concentration-Gradient Multichannel Flow-Stream Membrane Capacitive
           Deionization Cell for High Desalination Capacity of Carbon Electrodes
    • Authors: Choonsoo Kim; Juhan Lee, Pattarachai Srimuk, Mesut Aslan, Volker Presser
      Abstract: We present a novel multichannel membrane flow-stream capacitive deionization (MC-MCDI) concept with two flow streams to control the environment around the electrodes and a middle channel for water desalination. The introduction of side channels to our new cell design allows operation in a highly saline environment, while the feed water stream in the middle channel (conventional CDI channel) is separated from the electrodes with anion- and cation-exchange membranes. At a high salinity gradient between side (1000 mm) and middle (5 mm) channels, MC-MCDI exhibited an unprecedented salt-adsorption capacity (SAC) of 56 mg g−1 in the middle channel with charge efficiency close to unity and low energy consumption. This excellent performance corresponds to a fourfold increase in desalination performance compared to the state-of-the-art in a conventional CDI cell. The enhancement originates from the enhanced specific capacitance in high-molar saline media in agreement with the Gouy–Chapman–Stern theory and from a double-ion desorption/adsorption process of MC-MCDI through voltage operation from −1.2 to +1.2 V.Unsalted flow: A new multichannel membrane flow-stream capacitive deionization (MC-MCDI) concept is introduced. It includes two flow streams to control the environment around the electrodes, which allows to severely enhance the desalination capacity.
      PubDate: 2017-08-07T03:40:26.033312-05:
      DOI: 10.1002/cssc.201700967
       
  • Front Cover: A Strategy for the Simultaneous Synthesis of Methallyl
           Alcohol and Diethyl Acetal with Sn-β (ChemSusChem 23/2017)
    • Authors: Wenda Hu; Yan Wan, Lili Zhu, Xiaojie Cheng, Shaolong Wan, Jingdong Lin, Yong Wang
      Pages: 4664 - 4664
      Abstract: The Front Cover shows a strategy to simultaneously produce two important chemicals, namely, methallyl alcohol and diethyl acetal. They are produced from methacrolein in ethanol solvent at low temperature on Beta zeolites modified by tin (Sn-β catalysts). The catalyst pre-calcined in Ar (Sn-β-Ar) enables more Sn species to be exchanged into the framework as isolated tetrahedral Sn(IV), thus enhancing the catalytic activity of the Meerwein–Ponndorf–Verley reaction. The findings of Sn-β fine-tuned through different treatments are of great significance toward understanding and manipulating the complex reaction between α,β-unsaturated aldehydes and primary alcohols. More information can be found in the Full Paper by Hu et al. on page 4715 in Issue 23, 2017 (
      DOI : 10.1002/cssc.201701435).
      PubDate: 2017-12-08T03:05:10.466434-05:
       
 
 
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