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  Subjects -> COMPUTER SCIENCE (Total: 2016 journals)
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    - COMPUTER SCIENCE (1175 journals)
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COMPUTER SCIENCE (1175 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: 17)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 24)
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: 4)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 12)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 15)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 6)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 2)
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: 4)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 9)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 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: 27)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 7)
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: 6)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 18)
Advances in Computer Science : an International Journal     Open Access   (Followers: 15)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 52)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 27)
Advances in Human-Computer Interaction     Open Access   (Followers: 21)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 41)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access   (Followers: 4)
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: 5)
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: 12)
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: 2)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 15)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Applied System Innovation     Open Access  
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: 137)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
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: 9)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Big Data and Cognitive Computing     Open Access  
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 287)
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: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 49)
British Journal of Educational Technology     Hybrid Journal   (Followers: 140)
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: 2)
Cell Communication and Signaling     Open Access   (Followers: 2)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access   (Followers: 1)
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: 11)
Circuits and Systems     Open Access   (Followers: 15)
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: 14)
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: 55)
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   (Followers: 1)
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: 22)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 5)
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: 14)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 30)
Computer     Full-text available via subscription   (Followers: 91)
Computer Aided Surgery     Hybrid Journal   (Followers: 5)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 9)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 23)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 12)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 2)
Computer Music Journal     Hybrid Journal   (Followers: 18)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computer Science and Information Technology     Open Access   (Followers: 13)

        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  [1592 journals]
  • Towards High-Performance Aqueous Na-ion Batteries: Stabilizing the
           Solid/Liquid Interface for NASICON-Type Na2VTi(PO4)3 via the Use of
           Concentrated Electrolytes
    • Authors: Huang Zhang; Sangsik Jeong, Bingsheng Qin, Diogo Carvalho, Daniel Buchholz, Stefano Passerini
      Abstract: Aqueous Na-ion batteries may offer a solution to the cost and safety issues of high energy batteries. However, substantial challenges remain in the development of electrode materials and electrolytes enabling high performance and long cycle life. Herein we report the characterization of a symmetric Na-ion battery with NASICON-type Na2VTi(PO4)3 electrode material in conventional aqueous and "water-in-salt" electrolytes. Extremely stable cycling performance for 1000 cycles at high rate (20 C) is found with the highly concentrated aqueous electrolytes due to the formation of a resistive but protective interphase between the electrode and the electrolyte. These results provide an important insight for the development of aqueous Na-ion batteries with stable long-term cycling performance for large-scale energy storage.
      PubDate: 2018-02-22T04:31:57.945145-05:
      DOI: 10.1002/cssc.201800194
       
  • Aqueous hydrogenation of levulinic acid to 1,4-pentanediol over
           Mo-modified Ru/AC catalyst
    • Authors: Jinglei Cui; Jingjing Tan, Yulei Zhu, Fangqin Cheng
      Abstract: A highly efficient and green process was developed for direct conversion of levulinic acid to 1,4-pentanediol over Mo-modified Ru/activated-carbon(AC) catalyst in a continuous fix-bed reactor. Ru-MoOx/AC catalyst was found to be efficient for the aqueous-phase hydrogenation of levulinic acid to 1,4-pentanediol, on which high yield (96.7 mol%) of 1,4-pentanediol can be obtained under mild reaction conditions (70oC, 4MPa H2).
      PubDate: 2018-02-19T23:21:01.402986-05:
      DOI: 10.1002/cssc.201800038
       
  • Sufficient utilization of Zr4+ on improving the structure and surface
           property of the Ni-rich cathode materials for lithium ion batteries
    • Authors: Tao He; Yun Lu, Yuefeng Su, Liying Bao, Jing Tan, Lai Chen, Qiyu Zhang, Weikang Li, Shi Chen, Feng Wu
      Abstract: We applied Zr4+ ions in the outer layer of Ni0.8Co0.1Mn0.1(OH)2 through co-precipitation method. The distribution of the Zr4+ in the final cathode materials showed a gradient distribution due to ion migration during thermal treatment. The doped layer was confirmed via various analysis methods (EDS, XRD, XPS and TEM), implying that Zr4+ can not only occupy both TM slabs and Li slabs, but also form Li2ZrO3 layer on the surface as a fast ion conductive layer. The doped Zr4+ in the TM slabs can stabilize the crystal structure due to strong Zr-O bonding energy, and the doped Zr4+ in the Li slabs can act as pillar ions to improve the structural stability and reduce cation mixing. The gradient-doping can take advantage of the "pillar effect" while restrain the "blocking effect" of the pillar ions, thus reducing irreversible capacity loss and improving cycling and rate performance of the Ni-rich cathode materials. The capacity retention of the modified sample reached 83.2% after 200 cycles at 1 C (200 mA/g) between 2.8 to 4.5 V and the discharge capacity was up to 164.7 mAh/g at 10 C. This effective strategy is able to improve structure stability of the cathode material while reduce the amount of non-electrochemical active dopant due to gradient distribution of the dopant. In addition, the fast ion conductive layer of Li2ZrO3 on the surface can improve the rate performance of the cathode as well.
      PubDate: 2018-02-19T23:20:58.902984-05:
      DOI: 10.1002/cssc.201702451
       
  • Prominent performance for visible-light-driven water oxidation on an in
           situ N2-intercalated WO3 nanorod photoanode synthesized by a dual
           functional structure directing agent
    • Authors: Dong Li; Ryouchi Takeuchi, Debraj Chandra, Kenji Saito, Tatsuto Yui, Masayuki Yagi
      Abstract: Toward development of a photoanode for visible-light-driven water oxidation in solar water splitting cells, pure-monoclinic WO3 nanorod crystals with N2 intercalated into the lattice were synthesized using hydrazine (N2H4) with a "dual functional role" (an N atom source for the in-situ N2-intercalation and a structure directing role for the nanorod architecture) to gain the higher incident photon-to-current conversion efficiency (IPCE) at 420 nm compared with most WO3 electrodes reported previously.
      PubDate: 2018-02-19T04:45:22.816863-05:
      DOI: 10.1002/cssc.201702439
       
  • Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported
           onto CO2 Capture Materials
    • Authors: Hui-Juan Yang; Hong Yang, Yu-Hao Hong, Peng-Yang Zhang, Tao Wang, Li-Na Chen, Feng-Yang Zhang, Qi-Hui Wu, Na Tian, Zhi-You Zhou, Shi-Gang Sun
      Abstract: Cu is a unique catalyst for CO2 electroreduction, since it can catalyze CO2 reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO2 is considered to facilitate the activity and selectivity of CO2 reduction. Herein, a new strategy is presented for CO2 reduction with improved C2H4 selectivity on a Cu catalyst by using CO2 capture materials as the support at ambient pressure. N-doped carbon (NxC) was synthesized through high-temperature carbonization of melamine and l-lysine. We observed that the CO2 uptake capacity of NxC depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600–800 °C). The as-prepared CuO/NxC catalysts exhibit a considerably higher C2H4 faradaic efficiency (36 %) than CuO supported on XC-72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C2H4 faradaic efficiency and CO2 uptake capacity of the supports for CuO. The local high CO2 concentration near Cu catalysts, created by CO2 capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C2H4. This study demonstrates that pairing Cu catalysts with CO2 capture supports is a promising approach for designing highly effective CO2 reduction electrocatalysts.The higher the better: CuO supported on N-doped carbon, a CO2 capture material, exhibits high faradaic efficiency for CO2 electroreduction. The higher CO2 uptake capacity, the higher C2H4 selectivity. The local high CO2 concentration near the Cu catalysts, created by the CO2 capture materials, is proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C2H4.
      PubDate: 2018-02-15T07:45:57.597727-05:
      DOI: 10.1002/cssc.201702338
       
  • Tunable Bifunctional Activity of MnxCo3-xO4 Nanocrystals Decorated at
           Carbon Nanotubes for Oxygen Electrocatalysis
    • Authors: Tingting Zhao; Srinivas Gadipelli, Guanjie He, Matthew Ward, David Do, Peng Zhang, Zhengxiao Guo
      Abstract: Noble-metal free electrocatalysts are attractive for cathodic oxygen catalysis in alkaline membrane fuel cells, metal-air batteries and electrolysers. However, much of the structure-activity relationship is poorly understood. Here, comprehensive development of manganese cobalt oxide/nitrogen-doped multi-walled carbon nanotube hybrids (MnxCo3-xO4@NCNTs) is reported for highly reversible oxygen reduction and evolution reactions (ORR and OER). The hybrid structures are rationally designed by fine control of surface chemistry and synthesis conditions, including: tuning of functional groups at surfaces, congruent growth of nanocrystals with controllable phases and particle sizes, and ensuring strong coupling across catalyst-support interfaces. Electrochemical tests reveal distinctly different oxygen catalytic activities among the hybrids, MnxCo3-xO4@NCNTs. A nanocrystalline MnCo2O4@NCNTs (MCO@NCNTs) hybrid shows superior ORR activity, with a favourable onset potential and a high current density response, equivalent to the commercial Pt@C standard. Moreover, the hybrid structure exhibits tuneable and durable catalytic activities for both ORR and OER, with a lowest overall potential of 0.93 V. It is clear that the long-term electrochemical activities can be ensured by rational design of hybrid structures from the nanoscale.
      PubDate: 2018-02-14T09:35:35.600576-05:
      DOI: 10.1002/cssc.201800049
       
  • N-Annulated Perylene-Based Hole Transporters for Perovskite Solar Cells:
           The Significant Influence of Lateral Substituents
    • Authors: Yang Li; Rui Zhu, Junting Wang, Ze-Sheng Li, Niansheng Xu, Jidong Zhang, Peng Wang
      Abstract: The Cover Feature shows the critical influence of the lateral substituents on the molecular packing in organic semiconductor thin films. The methoxyphenyl lateral substituent in N-annulated perylene-based hole transporters can improve intermolecular stacking and improve connectivity between intermolecular aggregate domains in the solid films, leading to improved hole mobility and power conversion efficiency of the perovskite solar cells. More information can be found in the Full Paper by Li et al.
      PubDate: 2018-02-14T09:06:08.096122-05:
      DOI: 10.1002/cssc.201800255
       
  • Wet-imprinting of channel-type superstructures in nanostructured titania
           thin films at low temperatures for hybrid solar cells
    • Authors: Lin Song; Tianyi Wang, Volker Körstgens, Weijia Wang, Nitin Saxena, Christoph J. Schaffer, Thomas Fröschl, Nicola Hüsing, Sigrid Bernstorff, Peter Müller-Buschbaum
      Abstract: Hierarchically structured titania films, exhibiting interconnected foam-like nanostructures and large scale channel-type superstructures, are achieved in an energy saving way at low temperatures by a polymer template-assisted sol-gel synthesis in combination with a wet imprinting process. The surface morphology is probed with scanning electron microscopy and atomic force microscopy, while the inner morphology is characterized with grazing incidence small-angle x-ray scattering measurements. Compared to the initial hybrid films, the titania films showed reduced structure sizes caused by the polymer template removal. The UV/Vis measurements show an additional light scattering effect at various angles of light incidence in the hierarchical structured titania films, which results in a higher light absorption in the wet-imprinted active layer. To give a proof of viability, the titania films serve as photoanodes for dye-free hybrid solar cells. The dye-free layout allows for low-cost fabrication, avoids the problems related to dye bleaching and is more environmentally friendly. Under different angles of light incidence, the enhancement of short-circuit current density is in good agreement with the improvement of light absorption in the superstructured active layer, demonstrating a positive impact of superstructures on the photovoltaic performance of hybrid solar cells.
      PubDate: 2018-02-14T08:05:31.692989-05:
      DOI: 10.1002/cssc.201800129
       
  • Photoanode for aqueous dye-sensitized solar cells based on a novel
           multicomponent thin film
    • Authors: Samantha Husmann; Lucas Lima, Lucimara Roman, Aldo Jose Gorgatti Zarbin
      Abstract: Most of the dye-sensitized solar cells (DSSC) developed so far use organic electrolytes and water-sensible sensitizers. The search for aqueous DSSC, a promising technology for solar energy conversion, implies the finding of stable materials in aqueous solution. Herein we report the innovative utilization of Prussian blue (PB) as a sensitizer in a photoanode for DSSC. In this work, we describe a novel synthetic approach to a carbon nanotubes/TiO2/PB nanocomposite thin film. The photo-response is evaluated in a total aqueous electrolyte, achieving photocurrents of 600 μA cm-2.
      PubDate: 2018-02-13T14:30:25.741332-05:
      DOI: 10.1002/cssc.201702218
       
  • AuCu Aerogels with Intriguing Surface Electronic Modulation as Highly
           Active and Stable Electrocatalysts for Oxygen Reduction and Borohydride
           Oxidation
    • Authors: Jiali Wang; Fuyi Chen, Yachao Jin, Roy L Johnston
      Abstract: We for the first time reported the successful synthesis of self-assembled AuCu aerogels via a one-pot kinetically-controlled approach. The startling electronic modulation effect of Cu on Au was observed across the entire alloy composition range, where the optimal upshift of d-band center for the highest activities was 0.24 eV. Due to the combination of nanoporous architecture and robust electronic effect, the Au52Cu48 aerogels exhibit more enhanced catalytic performance for oxygen reduction reaction (ORR) and direct borohydride oxidation reaction (BOR) compared to the commercial Pt/C catalysts. The specific and mass ORR activities on Au52Cu48 aerogels are 4.5 and 6.3 times higher than Pt/C, respectively, with negligible activity decay even after 10,000 cycles and 40,000 s duration. For BOR, the Au52Cu48 aerogels also exhibit far better selectivity and activity relative to Pt/C. The newly AuCu aerogels show great potentials as a promising alternative for Pt-based catalyst in fuel cells.
      PubDate: 2018-02-13T12:05:29.052729-05:
      DOI: 10.1002/cssc.201800052
       
  • From Synthesis of Amino Acids and Peptides to Enzymatic Catalysis: A
           Bottom-Up Approach in Mechanochemistry
    • Authors: Carsten Bolm; José G. Hernández
      Abstract: In recent time, chemical reactions induced or facilitated by mechanical energy have gained recognition in diverse areas of chemical synthesis. In particular, mechanosyntheses of amino acids and short peptides, along with their application in catalysis have revealed a high degree of stability of peptide bonds in environments of harsh mechanical stress. These observations quickly led to a recent interest in developing mechanochemical enzymatic reactions. Experimentally, manual grinding, ball milling techniques and twin-screw extrusion technology have proven valuable to convey mechanical forces into a chemical synthesis. These practices have enabled establishing more sustainable alternatives for chemical synthesis, by reducing the use of organic solvents and waste production, thereby having a direct impact on the E-factor of the chemical process. In this Minireview we aim to describe the series of events that allowed the development of mechanochemical enzymatic reactions from a bottom-up perspective.
      PubDate: 2018-02-13T05:00:34.332088-05:
      DOI: 10.1002/cssc.201800113
       
  • High-efficiency and UV-stable Planar Perovskite Solar Cells Using
           Low-temperature Solution-processed Li-TFSI Doping C60 as Electron
           Transport Layers
    • Authors: Cheng Liu; Yi Yang, Yong Ding, Jia Xu, Xiaolong Liu, Bing Zhang, Jianxi Yao, Tasawar Hayat, Ahmed Alsaedi, Songyuan Dai
      Abstract: Efficient metal halide perovskite solar cells (PSCs) with regular structure typically use high temperature processed TiO2 electron transport layers (ETLs), suffering from high electron recombination and inherent UV instability. Here, we presented a low-temperature solution-processed lithium bis(trifluoromethanesulfo-nyl)imide (Li-TFSI) doped C60 (Li-C60) ETLs for high-efficiency and UV-stable planar PSCs with n-i-p architecture. We found that the simple Li-TFSI doping ensured a better energy match between the active layer and cathode, enhanced the electron mobility of ETL considerably, and even improved MAPbI3 crystallization, finally increased power conversion efficiencies (PCEs) from 15.3% to 17.8% with minor hysteresis effect. Meanwhile, it was demonstrated that replacing TiO2 with Li-C60 enabled PSCs to work much more stable under UV light in an air atmosphere and almost without degradation after 3000 hours under nitrogen atmosphere.
      PubDate: 2018-02-13T00:30:29.139313-05:
      DOI: 10.1002/cssc.201702248
       
  • Frequent Pitfalls in the Characterization of Electrodes Designed for the
           Electrochemical Energy Conversion and Storage
    • Authors: Aleksandar Zeradjanin
      Abstract: Enormous importance of the energy conversion and storage boosted research interest in various electrocatalytic materials. Characterization of solid/liquid interfaces during faradaic and non-faradaic processes is routinely conducted in many laboratories worldwide on a daily basis. This can be deemed as very positive tendency. However, careful insight into modern literature suggests frequent misuse of electroanalytical tools. This can have very negative implications and postpone overall development of electrocatalytic materials with desired properties. This work points out on some frequent pitfalls in electrochemical characterization, suggests potential solutions and above all encourages comprehensive analysis and in-depth thinking about electrochemical phenomena.
      PubDate: 2018-02-12T22:21:26.150658-05:
      DOI: 10.1002/cssc.201702287
       
  • Formation of Multi-layer Graphene Domains with Strong Sulfur-Carbon
           Interaction and Enhanced Sulfur Reduction Zones for Lithium-Sulfur Battery
           Cathodes
    • Authors: Saul Perez Beltran; Perla Beatriz Balbuena
      Abstract: A novel sulfur/graphene architecture emulates the Li-S battery cathode electrochemical behavior, promoting the S-C interaction through the edges of graphene sheets. A random mixture of S8 rings mixed with small graphene sheets is simulated at 64%-wt. S loading. Structural stabilization and S reduction calculations are performed with classical reactive molecular dynamics. This methodology allowed accounting for the collective behavior of the S and graphene structures. The S encapsulation induces ring opening and the S phase evolves into a distribution of small chain-like structures interacting with C through the graphene edges. This new arrangement of the S phase not only leads to a less pronounced volume expansion during S reduction but also to a different discharge voltage profile, in qualitative agreement with earlier reports on S encapsulation in microporous carbon structures. The Li2S phase grows around ensembles of parallel graphene nanosheets during S reduction. No diffusion of S or Li between graphene nanosheets is observed and extended Li2S domains bridging carbon ensembles are suppressed. The results emphasize the importance of morphology on the electrochemical performance of the composite material. The sulfur/graphene model outlined here provides new understanding of graphene effects on S reduction behavior and the role that van der Waals interactions may play in promoting formation of multi-layer graphene ensembles and small Li2S domains during S reduction.
      PubDate: 2018-02-12T12:00:29.471805-05:
      DOI: 10.1002/cssc.201702446
       
  • Highly dispersed metal carbide over ZIF-derived pyridinic-N doped carbon
           for CO2 enrichment and selective hydrogenation
    • Authors: Yunhua Li; Xiaohu Cai, Sijing Chen, Hua Zhang, Hongliang Zhang, Jinqing Hong, Binghui Chen, Dong-Hau Kuo, Wenju Wang
      Abstract: CO2 catalytic conversion to chemicals is a critical issue for energy and environmental. Among them, converting CO2 to CO has been regarded as a significant foundation to generate a series of liquid fuels and chemicals in a large scale. In this work, M/ZIF-8-C (M= Ni, Fe, Co and Cu) with highly dispersed metal carbide was prepared for CO2 selective hydrogenation. Under the same conditions of metal loadings, CO2 hydrogenation activity to CO follows the order: Ni/ZIF-8-C≈Fe/ZIF-8-C>Co/ZIF-8-C>Cu/ZIF-8-C. These catalysts are composed of carbide or metal supported on pyridinic N structure. ZIF-8-derived pyridinic nitrogen and carbide favor CO2 adsorption while dispersed Ni or Fe carbide and metal species serve as an active site for CO2 hydrogenation. Extraordinary catalytic performance of Ni supported catalyst results from high dispersion of metal and exposure of carbide. Based on high-sensitivity low-energy ion scattering (HS-LEIS) and line scan results, density functional theory (DFT) was used to understand reaction mechanism of CO2 selective hydrogenation over Ni/ZIF-8-C. The result presents that product CO derives mainly from the direct cleavage of C-O bond in CO2* rather than decomposition of COOH*. CO* desorption energy on Ni/ZIF-8-C is lower than that for further hydrogenation and dissociation. Comparison Ni/ZIF-8-C with ZIF-8-C indicates that synergy effects of highly dispersed metal or carbide and weak CO adsorption result in high CO selectivity for CO2 hydrogenation.
      PubDate: 2018-02-08T22:01:10.16629-05:0
      DOI: 10.1002/cssc.201800016
       
  • Facile photoinduced generation of hydroxyl radical on a nitrocellulose
           membrane surface and its application in the degradation of organic
           pollutants
    • Authors: Chao Tai; Shaodong Zhang, Yongguang Yin, Zhifeng Dai, Yanbin Li, Guibin Jiang, Yong Cai, Chunhua Huang, Jianbo Shi
      Abstract: Herein, we report on a simple, clean, and efficient method for generating hydroxyl radicals using a nitrocellulose membrane (NCM) under light of wavelengths greater than 280 nm. Hydroxyl radicals formed on the NCM surface, diffusing into the bulk solution under irradiation. Radical generation was shown to be dependent on the nature of the NCM and light, and independent of the properties of the bulk solution. The quantum yield for hydroxyl radical of the NCM was 1.72 × 10−4, approximately 2.46 times that of TiO2. This hydroxyl radical generation method was preliminarily applied in the photodegradation of organic pollutants, in which electrostatic interactions between the pollutant molecules and the NCM surface were found to play the key role. Further applications of the hydroxyl radical generation method described herein should be assessed.
      PubDate: 2018-02-08T04:50:23.430812-05:
      DOI: 10.1002/cssc.201800047
       
  • MoS2 quantum dots modified covalent triazine-based frameworks for enhanced
           photocatalytic hydrogen evolution
    • Authors: Qianqian Jiang; Long Sun, Jinhong Bi, Shijing Liang, Liuyi Li, Yan Yu, Ling Wu
      Abstract: MoS2 quantum dots (QDs) modified covalent triazine-based frameworks (MoS2/CTFs) composites are synthesized via an in situ photo-deposition method. MoS2 QDs are well distributed and stabilized on the layers of CTFs via the coordination of frameworks to MoS2. The synergistic QDs-on-sheet interactions between MoS2 and CTFs facilitate the interfacial charge transfer and separation. As a consequence, the composites exhibit outstanding photocatalytic activity and stability for hydrogen evolution under visible light irradiation (λ ≥ 420 nm) over pristine CTFs and MoS2 modified g-C3N4 (MoS2/g-C3N4) composite, making them promising as advanced materials for solar energy conversion.
      PubDate: 2018-02-06T06:26:32.100849-05:
      DOI: 10.1002/cssc.201702220
       
  • From Conventional Lewis Acids to Heterogeneous Montmorillonite K10,
           Eco-friendly Plant-based Catalysts used as Green Lewis Acids
    • Authors: Marie HECHELSKI; Alina GHINET, Brice LOUVEL, Pierrick DUFRENOY, Benoît RIGO, Adam DAÏCH, Christophe WATERLOT
      Abstract: The concept of green chemistry was appeared in the USA in the nineties. Since the publication of the 12 principles of this concept, many reactions in organic chemistry have been developed, chemical products have been synthesized under environmentally friendly conditions. Lewis acids-mediated synthetic transformations are by far the most numerous, best studied. However, the use of certain Lewis acids may cause environmental and human health hazards problems. The aim of this review is to point out the evolution of the Lewis acid catalyzed reactions from homogeneous liquid phase to solid phase in order to obtain the expected organic molecules under green, safe conditions. Particular interests will be focused on the recent developments, applications of bio-sourced catalysts using plants.
      PubDate: 2018-02-06T03:50:30.097446-05:
      DOI: 10.1002/cssc.201702435
       
  • CdS quantum dots decorated ultrathin WS2/g-C3N4 2D/2D heterojunction
           nanosheets for highly efficient photocatalytic hydrogen production under
           visible light
    • Authors: Yajun Zou; Jian-Wen Shi, Dandan Ma, Zhaoyang Fan, Linhao Cheng, Diankun Sun, Zeyan Wang, Chunming Niu
      Abstract: Two dimension/two dimension (2D/2D) stacking heterostructures are highly desirable in fabricating efficient photocatalysts because the face-to-face contact can provide maximized interfacial region between the two semiconductors, largely facilitating the migration of charge carriers. In this work, a novel WS2/g-C3N4 2D/2D nanosheet heterostructure decorated by CdS quantum dots (QDs) is reasonably designed for the first time. The optimized CdS/WS2/g-C3N4 without other co-catalyst exhibits a significantly enhanced photocatalytic H2 evolution rate of 1174.5 μmol h−1 g−1 under visible-light irradiation (λ>420 nm), which is nearly 67 times higher than that of the pure g-C3N4 nanosheets. The improved photocatalytic activity can be primarily attributed to the highly efficient charge transfer pathways built among the three components, which effectively accelerates the separation and transfer of photogenerated electrons and holes and thus inhibits their recombination. Moreover, the extended light absorption range also contributes to the excellent photocatalytic efficiency. In addition, the CdS/WS2/g-C3N4 photocatalyst shows excellent stability and reusability without apparent decay in the photocatalytic H2 evolution within four cycles in 20 h. It is believed that this work may shed light on the deliberately designed 2D/2D nanosheet heterostructures for more efficient visible-light-driven photocatalysts.
      PubDate: 2018-02-04T22:15:24.568398-05:
      DOI: 10.1002/cssc.201800053
       
  • Improving the Performance of Layered Oxide Cathode Materials with
           Football-Like Hierarchical Structure for Na-Ion Batteries by Incorporating
           Mg2+ into Vacancies in Na-ion Layers
    • Authors: Li Zheng-Yao; Huibo Wang, Dongfeng Chen, Kai Sun, Wenyun Yang, Jinbo Yang, Xiangfeng Liu, Songbai Han
      Abstract: Developing advanced cathode materials is still a great interest for sodium-ion batteries. Acceptable commercialization of sodium-ion batteries relies on the design and exploitation of suitable electrode materials. This study offers a novel insight of material design into exploiting high performance P2-type cathode materials for sodium-ion batteries. Skillfully incorporating Mg2+ into some intrinsic Na+ vacancies in Na-ion layers can achieve high-performance P2-type cathode materials for sodium-ion batteries. The materials prepared by co-precipitation approach show well-defined morphology of secondary football-like hierarchical structures. Neutron power diffraction and refinement results demonstrate the incorporation of Mg2+ into intrinsic vacancies can enlarge the space for Na-ion diffusion, can increase the d-spacing of (002) peak and the size of slabs, but reduces the chemical bond length, thus resulting in an enhanced rate capability and cycling stability. The incorporation of Mg2+ into available vacancies and such unique morphology make Na0.7Mg0.05Mn0.8Ni0.1Co0.1O2 the promising cathode, which even can be charged and discharged at ultra-high current density of 2000mA g-1 with a great specific capacity of 60mAh g-1. The work provides a new insight to design electrode materials for sodium-ion batteries.
      PubDate: 2018-02-04T21:50:53.221543-05:
      DOI: 10.1002/cssc.201702322
       
  • Zwitterionic HBr carriers for the synthesis of 2-bromopropionic acid from
           lactide
    • Authors: Jakob Albert; Matthias Kehrer, Julian Mehler, Nicola Taccardi, Jens Nagengast, Julian Kadar, Dimitris Collias, Peter Dziezok, Peter Wasserscheid
      Abstract: A convenient and highly efficient way of synthesizing 2-bromopropionic acid (2-BrPA) from lactide is presented. The procedure uses ionic liquids obtained from the addition of HBr to ammonium-based zwitterions as solvent and bromination agent. The buffered HBr acidity, high polarity, and charge stabilizing character of the IL enable 2-BrPA synthesis with excellent selectivity. The best results were obtained with the imidazolium-based IL 1-(4-butane sulfonic acid)-3-methyl imidazolium bromide ([MIMBS]Br). It was found that adjustment of the right HBr loading and the water content of the IL are crucial parameters for the bromination reaction. The formed 2-BrPA product can be selectively isolated via extraction from the IL and the unconverted substrate remains in the [MIMBS]Br for the next run. Successful recycling of the IL over four cycles was demonstrated.
      PubDate: 2018-02-01T09:10:59.059747-05:
      DOI: 10.1002/cssc.201702369
       
  • Transparent Wood Smart Windows: Polymer Electrochromic Devices Based on
           Poly(3,4-Ethylenedioxythiophene):Poly(Styrene Sulfonate) Electrodes
    • Authors: Augustus W. Lang; Yuanyuan Li, Michel De Keersmaecker, D. Eric Shen, Anna M. Österholm, Lars Berglund, John R. Reynolds
      Abstract: Transparent wood composites, with their high strength and toughness, thermal insulation, and excellent transmissivity, offer a route to replace glass for diffusely transmitting windows. Here, conjugated-polymer-based electrochromic devices (ECDs) that switch on-demand are demonstrated using transparent wood coated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a transparent conducting electrode. These ECDs exhibit a vibrant magenta-to-clear color change that results from a remarkably colorless bleached state. Furthermore, they require low energy and power inputs of 3 mWh m−2 at 2 W m−2 to switch due to a high coloration efficiency (590 cm2 C−1) and low driving voltage (0.8 V). Each device component is processed with high-throughput methods, which highlights the opportunity to apply this approach to fabricate mechanically robust, energy-efficient smart windows on a large scale.Let there be light: Color-changing electrochromic devices (ECDs) are demonstrated on transparent wood substrates for energy-saving smart windows and roofing. Highly conducting poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) electrodes are solution-processed with a dilute acid post treatment. The transparent wood (TW)-based ECDs show vibrant color-to-colorless switching with low energy and power consumption.
      PubDate: 2018-02-01T05:45:36.892356-05:
      DOI: 10.1002/cssc.201702026
       
  • Free-standing hybrid graphene paper encapsulating nanostructures for high
           cycle-life supercapacitors
    • Authors: Xinyan Jiao; Qingli Hao, Xifeng Xia, Wu Lei, Yu Ouyang, Haitao Ye, Daniel Mandler
      Abstract: The incorporation of "spacers" between graphene sheets has been investigated as an effective method to improve the electrochemical performance of graphene papers for supercapacitors. Here we report the design of free-standing GP@NiO and GP@Ni hybrid graphene papers with encapsulating NiO nanoclusters and Ni nanoparticles into graphene sheets through electrostatic assembly and subsequent vacuum filtration. The encapsulated NiO nanoclusters and Ni nanoparticles can mitigate the restack of graphene sheets, providing sufficient spaces for high-speed ion diffusion and electron transport. In addition, the "spacers" strongly bind to graphene sheets, which can efficiently improve the electrochemical stability. Therefore, at current density of 0.5 A g-1, the GP@NiO and GP@Ni electrodes exhibit higher specific capacitance of 306.9 and 246.1 F g-1 than the GP electrode (185.7 F g-1). The GP@NiO and GP@Ni electrodes exhibit capacitance retention of 98.7% and 95.6% after 10000 cycles, demonstrating an outstanding cycling stability. Additionally, the GP@NiO//GP@Ni delivers excellent cycle stability (93.7% after 10000 cycles) and large energy density. These free-standing encapsulated hybrid graphene papers have great potential as electrode for high-performance supercapacitors.
      PubDate: 2018-01-31T22:11:22.497137-05:
      DOI: 10.1002/cssc.201702283
       
  • Electrocatalytic and Photocatalytic Reduction of CO2 to CO by Cobalt(II)
           Tripodal Complexes: Low Overpotentials, High Efficiency and Selectivity
    • Authors: Di-Chang Zhong; Jia-Wei Wang, Hai-Hua Huang, Jia-Kai Sun, Ting Ouyang, Tong-Bu Lu
      Abstract: The reduction of carbon dioxide (CO2) has been considered as an appealing approach to mitigate global warming and to provide renewable carbon-based fuels. Rational design of efficient, selective and inexpensive catalysts with low overpotentials is urgently desired. Herein, we report four cobalt(II) tripodal complexes as catalysts for CO2 reduction to CO in a MeCN/H2O (v:v = 4:1) solution. It has been found that the replacement of the pyridyl groups in ligands with less basic quinolinyl groups will greatly reduce the required overpotential of CO2-to-CO conversion down to 200-380 mV. Benefited from the low overpotentials, a photocatalytic system for CO2-to-CO conversion has been successfully constructed, where an optimal turn-over number (TON) of 10,650 ± 750, a turn-over frequency (TOF) of 1,150 ± 80 h-1 and the selectivity to CO of almost 100% can be achieved. These outstanding catalytic performances are further revealed by DFT calculations.
      PubDate: 2018-01-31T12:07:15.907533-05:
      DOI: 10.1002/cssc.201702280
       
  • Mechanochemical Decomposition of Crystalline Cellulose in the Presence of
           Protonated Layered Niobium Molybdate Solid Acid Catalyst
    • Authors: Shogo Furusato; Atsushi Takagaki, Shigenobu Hayashi, Akio Miyazato, Ryuji Kikuchi, S. Ted Oyama
      Abstract: Direct depolymerization of crystalline cellulose into water-soluble sugars by solvent-free ball milling was examined in the presence of a strongly acidic layered metal oxide, HNbMoO6, resulting in full conversion with 72% yield of water-soluble sugars. Measurements by 13C cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy and x-ray diffraction revealed that amorphization of cellulose occurred rapidly within 10 min. Scanning electron microscopy equipped with an energy dispersive x-ray indicated that the substrate and the catalyst were well mixed during milling. The time-course of the product distribution showed that most of the resultant water-soluble sugars were produced not via successive degradation of oligosaccharides but via direct depolymerization of cellulose long chains. The products included glucose, mannose and cello-oligomers as well as anhydrosugars. Addition of small amounts of polar solvents increased the sugar yield, while the further addition of water decreased the selectivity to anhydrosugars. Calculations of the mechanical energy required for the ball milling process showed that 0.02% was utilized for the chemical transformation under the conditions examined in this study.
      PubDate: 2018-01-30T04:55:37.808295-05:
      DOI: 10.1002/cssc.201702305
       
  • Sandwich-structured Icosahedral PtNi Alloy Nanocrystalline
           Electrocatalyst: from the Growth Mechanism to its Oxygen Reduction
           Activity
    • Authors: Renxiu Tian; Shuiyun Shen, Fengjuan Zhu, Liuxuan Luo, Xiaohui Yan, Guanghua Wei, Junliang Zhang
      Abstract: Engineering the structure of Pt alloy offers an effective way to the design of high performance electrocatalysts. Herein, we synthesize a sandwich-structured, icosahedral Pt2.1Ni catalyst via hot injection method. Its growth is found involving three steps, i.e., burst nucleation of Pt atoms to form Pt-enriched core, heterogeneous nucleation of Ni atoms onto Pt core to form Ni-enriched interlayer, and kinetic controlled growth of Pt-enriched shell. The Pt-enriched core protects the nanostructure from collapse and mitigate the strain change caused by lattice mismatch, and thus enhances structure stability. The Ni-enriched interlayer induces the electronic modification of the outermost Pt shell, and in turn tunes the activity. The Pt-enriched shell provides more active sites via the exposure of (111) facets and retards the dissolution of Ni atoms. As a result, this sandwich-structure enables impressive electrocatalytic activity (0.91 mA cm-2 and 0.32 A 〖mg〗_Pt^(-1)@ 0.9 V) and duability.
      PubDate: 2018-01-29T23:55:59.213058-05:
      DOI: 10.1002/cssc.201800074
       
  • Electronic Structure Oriented Molecular Design of Phenanthrenequinone
           Derivatives for Organic Cathode Materials
    • Authors: Liu-Bin Zhao; Shu-Ting Gao, Rongxing He, Wei Shen, Ming Li
      Abstract: Conjugated carbonyl compounds have become the most promising type of organic electrode materials for rechargeable lithium ion batteries because only they can achieve simultaneously high energy density, high cycling stability, and high power density. In this work, we have performed first-principles DFT calculations to explore the fundamental rules that how the electronic structure and redox property of a typical conjugated carbonyl compound phenanthrenequinone (PQ) is modified by the heteroaromatic building blocks. Such a molecular design strategy allows the improvement of discharge potential in case that the specific capacity remains nearly unchanged. The correlation between the electronic structures and redox properties for the designed PQ derivatives is systematically discussed. It is demonstrated that the discharge potential of PQ derivatives depends strongly on the frontier orbital levels, the electric potential, and the Li bonding configurations. The most interesting finding in this study is that the ESP maps show visible displays of molecular electric structures and can be applied to understand how the redox properties of PQ derivatives are modified by the heteroaromatic building blocks. Among all the designed PQ derivatives, B02 exhibits the highest discharge voltage of 3.22 V vs Li+/Li; D05 with simultaneously large capacity density and high reduction potential gives the largest energy density of 841 Wh kg−1.
      PubDate: 2018-01-29T22:02:31.934345-05:
      DOI: 10.1002/cssc.201702344
       
  • X-Structured α-FeOOH with Enhanced Charge Separation for
           Visible-Light-Driven Photocatalytic Overall Water Splitting
    • Authors: Tainqi Wang; Zhifeng Jiang, Ka Him Chu, Dan Wu, Bo Wang, Hongli Sun, Ho Yin Yip, Taicheng An, Huijun Zhao, Po Keung Wong
      Abstract: Photocatalytic overall water splitting (POWS) is a promising route for converting solar energy into green and sustainable energy. Herein, we report a facile hydrothermal approach to fabricate X-structured α-FeOOH photocatalysts enclosed with high-index facets for POWS. The X-structured α-FeOOH photocatalysts exhibited enhanced visible-light-driven (VLD) POWS activities in comparison with that of FeOOH without X-structures, with the maximum H2 and O2 evolution rate of 9.2 and 4.7 μmol·h-1·g-1, respectively. The morphology and particle size of α-FeOOH could be controlled by adjusting the NH4F concentration in the precursors. The photo-depositions of Pt and RuO2 revealed the specially separated reduction and oxidation centers on the surface of X-structured FeOOH, with the oxidation active sites selectively locating on the edges of FeOOH X-structures. The electrochemical experiments further affirmed the enhanced charge separation of X-structured FeOOH. The smaller particle size and unique X-structures of α-FeOOH photocatalyst were evidenced to enhance the POWS performance due to the large specific surface area, high-ratio exposure of {3 } facets, high electron transfer efficiency and effective separation of photo-generated electron-hole pairs. The current study revealed that the X-structured α-FeOOH products could serve as cost-effective and stable photocatalysts for POWS.
      PubDate: 2018-01-29T22:02:23.648771-05:
      DOI: 10.1002/cssc.201800059
       
  • Monodisperse Nano-single Crystal Coalesced TePtFe Nanotubes as
           High-performing Bifunctional Electro-catalysts for ORR and HER
    • Authors: Wenqiang Li; Ibrahim Saana Amiinu, Bei Ye, Zhe Wang, Jiawei Zhu, Zongkui Kou, Shichun Mu
      Abstract: Currently, the multicomponent Pt-based alloy as promising electrocatalyst has been applied to improve the catalysis and lower the usage of noble metal Pt. Herein, we report on a Te nanowire (NW) derived ternary TePtFe nanotube (NT) electrocatalyst prepared by the Kirkendall effect. The formed TePtFe NT consisting of small single crystal nanoparticles and voids with the open-end and hollow structure, presents ultrahigh catalytic activity and stability for both oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Its ORR specific activity and mass activity are 8.5 times and 2.4 times improved compared to commercial Pt catalysts, respectively. It is also impressive that, for HER an ultralow overpotential of 28.1 mV at 10 mA cm-2 can be achieved, lower than that of Pt (51.8 mV) catalysts in 0.1M HClO4, and the activity improved even after 5000 cycle lifes. This work exhibits that TePtFe NTs can be employed as ultrahigh catalytic activity and stability nanocatalysts for fuel cells and hydrogen production.
      PubDate: 2018-01-29T11:50:27.620818-05:
      DOI: 10.1002/cssc.201702403
       
  • Key properties towards citrus nanostructured cellulose processing: A
           rigorous DoE study of the Hy-MASS concept
    • Authors: Avtar Singh Matharu; Eduardo de Melo, Javier Remon, Alima Abdulina, Shuting Wang, Eero kontturi
      Abstract: A detailed design of experiment (DoE) study to investigate cause-effect interaction of three process variables: temperature (120-200 °C), holding time (0-30 min) and concentration (1.4-5.0 wt.%), on processing of citrus cellulosic matter using acid-free microwave-assisted selective scissoring (Hy-MASS) is reported. Analysis of variance (ANOVA) showed that post microwave processing, yield of cellulosic matter (25-72 %), decomposition temperature (345-373 °C) and crystallinity index (34-67%) were strongly affected by temperature. SEM and TEM analyses showed that the isolated cellulosic matter was heterogeneous comprising a mixture of micro- and nano-fibres more akin to microfibrillated cellulose (MFC) at low processing temperatures and tending towards aggregated cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) at higher temperatures. The water holding capacity of the processed cellulosic matter (15-27 g H2O·g-1) was higher than the original feedstock or previously reported values. The average molecular weight of the cellulosic matter (113.6-1095.9 kg·mol-1) decreased significantly by a factor of 10 above 180 °C, invoking significant scissoring of the cellulosic chains. The process energy input and costs varied between 0.142-0.624 kWh and 13-373 €/kg, respectively, and were found to be strongly dependent of the reaction time.
      PubDate: 2018-01-29T10:35:41.457611-05:
      DOI: 10.1002/cssc.201702456
       
  • Review of ambient CO2 effect on anion exchange membranes fuel cells
    • Authors: Noga Ziv; William E Mustain, Dario R Dekel
      Abstract: Over the past 10 years, there has been a surge of interest in anion exchange membrane fuel cells (AEMFCs) as a potentially lower cost alternative to proton exchange membrane fuel cells (PEMFCs). Recent work has shown that AEMFCs achieved nearly identical performance to state-of-the-art PEMFCs; however, much of that data has been collected while feeding CO2-free air or pure oxygen to the cathode. Usually, removing CO2 from the oxidant is done in order to avoid the detrimental effect of CO2 on AEMFC performance, due to carbonation where CO2 reacts with the OH- anions, forming HCO3- and CO32-. In spite of the crucial importance of this topic for the future development and commercialization of AEMFCs, unfortunately there have been very few investigations devoted to this phenomenon and its effects. Much of the data available in the literature is widely spread out and there currently does not exist a resource that researchers in the field, or those looking to enter the field, can use as a reference text that explains the complex influence of CO2 and HCO3-/CO32- on all aspects of AEMFC performance. The purpose of this review is to summarize the experimental and theoretical work that has been reported in the literature for the effect of ambient CO2 on AEMFCs. This systematic review intends to create a single comprehensive account of what is known regarding how CO2 behaves in AEMFCs to date, as well as identify the most important areas for future work in this field.
      PubDate: 2018-01-27T10:50:23.961442-05:
      DOI: 10.1002/cssc.201702330
       
  • Highly Capacitive Storage Performance of the S and N co-Doped Mesoporous
           Graphene
    • Authors: Xinlong Ma; Daowei Gao
      Abstract: Mesoporous graphene is synthesized based on the chemical vapor deposition methodology using the heavy MgO flakes as substrates in the fluidized bed reactor. After that, S and N co-incorporation into graphene frameworks is realized by the reaction between C atoms and thiourea molecules. The as-obtained S and N co-doped mesoporous graphene (SNMG) exhibits remarkable capacitive energy-storage behaviors contributed by the well-developed pore channels in terms of the symmetric supercapacitor and Li ion hybrid capacitor (LIHC). The ultrahigh durability of the SNMG/SNMG symmetric supercapacitor is demonstrated by the long-term cycling in which no capacitance decay is found after 20000 cycles. A LIHC constructed by the commercial Li4Ti5O12 (LTO) as anode and SNMG as cathode, is capable of delivering the much enhanced Li storage ability and better rate capability as compared to that of AC/LTO LIHC. Moreover, SNMG/LTO LIHC exhibits the maximum energy and power densities of 86.2 Wh kg-1 and 7443 W kg-1 and maintains a 87% capacitance retention after 2000 cycles.
      PubDate: 2018-01-27T05:45:22.551251-05:
      DOI: 10.1002/cssc.201702457
       
  • Designing Cu-based Bimetallic Nanoparticles for CO2 Adsorption and
           Activation
    • Authors: James Dean; Yahui Yang, Natalie Austin, Götz Veser, Giannis Mpourmpakis
      Abstract: Cu-based nanoparticles (NPs) are promising candidates for the catalytic hydrogenation of CO2 to useful chemicals due to their low cost. However, CO2 adsorption and activation on Cu is not feasible. In this work we demonstrate a computational framework that identifies Cu-based bimetallic NPs able to adsorb and activate CO2, based on Density Functional Theory (DFT) calculations. We screen a series of heteroatoms on Cu-based NPs based on their preference to occupy a surface site on the NP and to adsorb and activate CO2. We revealed two descriptors for CO2 adsorption on the bimetallic NPs, the heteroatom (i) local d-band center and (ii) electropositivity, which are both driving an effective charge transfer from the NP to CO2. We identified the CuZr bimetallic NP as a candidate nanostructure for CO2 adsorption and showed that although the Zr sites can be oxidized due to their high oxophilicity, they are still able to strongly adsorb and activate CO2. Importantly, our computational results are verified with targeted synthesis, characterization and CO¬2 adsorption experiments demonstrating that i) Zr segregates on the surface of Cu, ii) Zr is oxidized to form a bimetallic mixed CuZr oxide catalyst, which iii) can strongly adsorb CO2, whereas Cu NPs cannot. Overall our work highlights the importance of generating binding sites on a NP surface based on (catalyst) stability and electronic structure properties, which can lead to the design of more effective CO2 reduction catalysts.
      PubDate: 2018-01-26T10:15:29.661877-05:
      DOI: 10.1002/cssc.201702342
       
  • The Effect of Dopant-Free Hole Transport Polymers P3HT, P3TI and TQ1 on
           Charge Generation and Recombination in Cesium-Bismuth-Iodide Solar Cells
    • Authors: Huimin Zhu; Malin B. Johansson, Erik Johansson
      Abstract: The photovoltaic characteristics of CsBi3I10 based solar cells with three dopant-free hole conducting polymers; TQ1, P3TI and P3HT, are investigated. The effect on charge generation and charge recombination in the solar cells using the different polymers are studied and the results show that the polymer strongly affects the device properties. Interestingly, for the solar cell with TQ1 polymer the photon to current conversion spectrum is highly improved in the red wavelength region, suggesting that the polymer also contributes to the photocurrent generation in this case. This report provides a new direction for further optimization of bismuth-halide solar cells by using dopant free hole transporting polymers and shows that the energy levels and the interaction between the bismuth-halide and the conducting polymers are very important for the efficiency of the solar cells.
      PubDate: 2018-01-26T02:45:36.63374-05:0
      DOI: 10.1002/cssc.201702169
       
  • Lignocellulose liquefaction to biocrude - a tutorial review
    • Authors: Jean-Paul Lange
      Abstract: After 40 years of R&D, liquefaction technologies are now being demonstrated at 200-3000 t/a scale to convert lignocellulosic biomass to biocrudes for use as heavy fuel or for upgrading to biofuels. This review attempts to present the various facets of the liquefaction process in a tutorial manner. Emphasis is placed on liquefaction in high-boiling solvents, with regular reference to liquefaction in subcritical water or other light-boiling solvents. Reaction chemistry, solvent selection, role of optional catalyst as well as biocrude composition and properties are discussed in depth. Challenges in biomass feeding and options for biocrude-solvent separation are addressed. Process concepts are reviewed and demonstration/commercialization efforts are presented.
      PubDate: 2018-01-24T08:30:25.707366-05:
      DOI: 10.1002/cssc.201702362
       
  • Aromatic Polyimide/Graphene Composite Organic Cathodes for Fast and
           Sustainable Lithium-Ion Batteries
    • Authors: Hailong Lyu; Peipei Li, Jiurong Liu, Shannon Mahurin, Jihua Chen, Dale K. Hensley, Gabriel M. Veith, Zhanhu Guo, Sheng Dai, Xiao-Guang Sun
      Abstract: A composite organic cathode material based on aromatic polyimide (PI) and highly conductive graphene was prepared through a facile in situ polymerization method for application in lithium-ion batteries. The in situ polymerization generated intimate contact between PI and electronically conductive graphene, resulting in conductive composites with highly reversible redox reactions and good structure stability. The synergistic effect between PI and graphene enabled not only a high reversible capacity of 232.6 mAh g−1 at a charge–discharge rate of C/10 but also exceptionally high-rate cycling stability, that is, a high capacity of 108.9 mAh g−1 at a very high charge–discharge rate of 50C with a capacity retention of 80 % after 1000 cycles. This improved electrochemical performance resulted from the combination of stable redox reversibility of PI and high electronic conductivity of the graphene additive. The graphene-based composite also exhibited much better performance than composites based on multi-walled carbon nanotubes and the conductive carbon black C45 in terms of specific capacity and long-term cycling stability under the same charge–discharge rates.Polyimide and graphene composites: A composite organic cathode based on aromatic polyimide and highly conductive graphene enables not only a high reversible capacity at a charge–discharge rate of C/10 but also an exceptional high-rate cycling stability, that is, a high capacity is achieved at a very high rate of 50C with a capacity retention of 80 % after 1000 cycles.
      PubDate: 2018-01-24T02:40:44.3193-05:00
      DOI: 10.1002/cssc.201702001
       
  • Bifunctional oxygen reduction/oxygen evolution activity of mixed Fe-Сo
           oxide nanoparticles with variable Fe:Co ratios supported on multi-walled
           carbon nanotubes
    • Authors: Justus Masa; Karina Elumeeva, Mariya Kazakova, Dulce Maria Morales, Danea Medina, Alexander Selyutin, Georgiy Golubtsov, Yurii Ivanov, Vladimir Kuznetzov, Andrey Chuvilin, Hendrik Antoni, Martin Muhler, Wolfgang Schuhmann
      Abstract: We present here a facile strategy for synthesis of Fe-Co mixed metal oxide nanoparticles supported on, and embedded inside high purity oxidized multi-walled carbon nanotubes (MWCNTs) of narrow diameter distribution as effective bifunctional catalysts able to reversibly drive the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in alkaline solutions. Variation of the Fe:Co ratio resulted in a pronounced trend in the bifunctional ORR/OER activity. Controlled synthesis and in-depth characterization enabled the identification of an optimal Fe:Co composition, which afforded a low OER/OER reversible overvoltage of only 0.831 V, taking the OER at 10 mA cm-2 and the ORR at -1 mA cm-2. Importantly, the optimal catalyst with a Fe:Co ratio of 2:3 exhibited very promising long-term stability with no evident change in the potential for both the ORR and the OER after 400 charge/discharge (OER/ORR) cycles at 15 mA cm-2 in 6 M KOH. Moreover, detailed investigation of the structure, size and phase composition of the mixed Fe-Co oxide nanoparticles, as well as their localization (inside of or on the surface of the MWCNTs) revealed insight of the possible contribution of the individual catalyst components and their synergistic interaction on the catalysis.
      PubDate: 2018-01-23T06:40:48.902341-05:
      DOI: 10.1002/cssc.201702381
       
  • Novel low temperature, low energy and high efficiency pretreatment
           technology for large wood chips with a redox couple catalyst
    • Authors: Parikshit Gogoi; Zhe Zhang, Zhishuai Geng, Wei Liu, Weize Hu, Yulin Deng
      Abstract: Pretreatment of lignocellulosic biomass plays a vital role in the conversion of cellulosic biomass to bioethanol, specially for softwoods and hardwoods. Although many pretreatment technologies have been reported so far, but barely a few pretreatment methods can handle large sized wood chips directly. To improve the efficiency of this pretreatment all the existing technologies need to grind wood into small particles, which is an extreme energy consuming process. Herein, for the first time, we report a simple, effective and low temperature (~100 oC) process for pretreatment of hardwood (HW) and softwood (SW) chips directly by using a catalytic system of FeCl3/NaNO3 redox couple (FCSNRC). The pretreatment experiments were systematically conducted and a conversion of 71.53% and 70.66% of cellulose to sugar could be obtained even large sized hard and softwood chips being directly used. The novel method reported here overcame one of the critical barriers in biomass to biofuel conversion and both grinding and thermal energies can be significantly reduced.
      PubDate: 2018-01-23T02:55:39.492458-05:
      DOI: 10.1002/cssc.201702090
       
  • Atmospheric dry hydrogen plasma reduction of inkjet-printed flexible
           graphene oxide electrodes
    • Authors: Tomas Homola; Jan Pospišil, Richard Krumpolec, Pavel Souček, Petr Dzik, Martin Weiter, Mirko Černák
      Abstract: This contribution presents a low-temperature method for dry hydrogen plasma reduction of inkjet-printed flexible graphene oxide (GO) electrodes, an approach compatible with processes envisaged for the manufacture of flexible electronics. The processing of GO to reduced graphene oxide (rGO) was performed in 1-64 seconds, and sp2/sp2+sp3 carbon concentration increased from approx. 20% to 90%. Since the plasma reduction was associated with an etching effect, the optimal reduction time occurred between 8 and 16 seconds. The surface showed good mechanical stability when deposited on PET flexible foils and significantly lower sheet resistance after plasma reduction. The method for dry plasma reduction presented herein could be important for large area hydrogenation and reduction of graphene oxide flexible surfaces, with present and potential applications in a wide variety of emerging technologies.
      PubDate: 2018-01-22T08:21:04.259232-05:
      DOI: 10.1002/cssc.201702139
       
  • Carbon Molecular Sieve Membranes Derived from Tröger's Base-Based
           Microporous Polyimide for Gas Separation
    • Authors: Jian Jin; Zhenggong Wang, Huiting Ren, Shenxiang Zhang, Feng Zhang
      Abstract: Carbon molecular sieve (CMS) membrane based membrane attracts great attentions because of their outstanding gas separation performance. Polymer precursor is one of key points for preparation of high performance CMS. Tröger's base (TB) group is constructed by a bridged bicyclic amine. Such a bicyclic bridged stereo structure endows TB unit with highly contorted and great shape-persistent properties. In this work, a TB-based PIM-PI (TB-PI) is used as a polymer precursor to prepare CMS for the first time. By optimizing the thermal treatment condition, three CMS membranes treated under different soaking temperatures named TB-CMS-550, TB-CMS-650, and TB-CMS-800 were obtained. The TB-CMS membranes exhibit outstanding separation performance with comprehensive separation performances largely exceeding the 2008 updated Robeson upper bound for O2/N2, H2/CH4, H2/N2 and CO2/CH4 gas pairs, among which the permeability of H2 and CO2 up to 15000 barrer and simultaneously selectivity of H2/CH4 up to 200 and CO2/CH4 up to 110. This compresensive separation performance is superior to almost all of the CMS membranes derived from traditional polyimide precursors reported so far. Our work provides an effective strategy for fabricating high-performance CMS membranes through designing the stereo-structure of polymer precursor. The superior separation performance as compared to the stae-of-the-art conventional polyimides makes the TB-CMS membranes highly competitive for application.
      PubDate: 2018-01-19T03:30:56.574129-05:
      DOI: 10.1002/cssc.201702243
       
  • Deep Eutectic Solvent Aqueous Solutions as Efficient Media for the
           Solubilization of Hardwood Xylans
    • Authors: Eduarda S. Morais; Patrícia V. Mendonça, Jorge F. J. Coelho, Mara G. Freire, Carmen S. R. Freire, João A. P. Coutinho, Armando J. D. Silvestre
      Abstract: This work contributes to the development of integrated lignocellulosic-based biorefineries by the pioneering exploitation of hardwood xylans by solubilization and extraction in deep eutectic solvents (DES). DES formed by choline chloride and urea or acetic acid were initially evaluated as solvents for commercial xylan as a model compound. The effects of temperature, molar ratio, and concentration of the DES aqueous solutions were evaluated and optimized by using a response surface methodology. The results obtained demonstrated the potential of these solvents, with 328.23 g L−1 of xylan solubilization using 66.7 wt % DES in water at 80 °C. Furthermore, xylans could be recovered by precipitation from the DES aqueous media in yields above 90 %. The detailed characterization of the xylans recovered after solubilization in aqueous DES demonstrated that 4-O-methyl groups were eliminated from the 4-O-methylglucuronic acids moieties and uronic acids (15 %) were cleaved from the xylan backbone during this process. The similar Mw values of both pristine and recovered xylans confirmed the success of the reported procedure. DES recovery in four additional extraction cycles was also demonstrated. Finally, the successful extraction of xylans from Eucalyptus globulus wood by using aqueous solutions of DES was demonstrated.New media provides the solution: Deep eutectic solvents formed by choline chloride and urea in aqueous solutions display excellent ability to solubilize hardwood xylans and show great potential for the extraction of these polysaccharides from hardwoods in an integrated biorefinery context.
      PubDate: 2018-01-18T08:01:43.378652-05:
      DOI: 10.1002/cssc.201702007
       
  • N-modified NiO Surface for Superior Alkaline Hydrogen Evolution
    • Authors: Le Zhang; Peng Fei Liu, Yu Hang Li, Meng Yang Zu, Xu Li, Zheng Jiang, Yun Wang, Huijun Zhao, Huagui Yang
      Abstract: Boosting the sluggish kinetics of hydrogen evolution reaction in alkaline environments is the key for large application of water-alkali and chlor-alkali electrolysis. Herein, for the first time, we use nitrogen atoms to precisely modulate electrochemical active sites on the surface of nickel oxide with low coordinated oxygen atoms, to achieve enhanced kinetics of alkaline hydrogen evolution. Theoretical and experimental results demonstrate that the surface charge redistribution after modulation simultaneously facilitates the initial water dissociation step, as well as the subsequent recombination of Had from low coordinated oxygen sites and desorption of OH-ad from nickel sites, thus accelerating the overall hydrogen evolution process. The N-modulated nickel oxide enriched in low coordinated oxygen atoms exhibits significantly enhanced activity with a small overpotential of -100 mV at the current density of -10 mA cm-2 and a robust stability over 90 h for hydrogen evolution in 1.0 M KOH.
      PubDate: 2018-01-18T07:55:39.921625-05:
      DOI: 10.1002/cssc.201702371
       
  • Sustainable synthesis of oxalic (and succinic) acid via aerobic oxidation
           of C6 polyols by using M@CNT/NCNT (M=Fe, V) based catalysts in mild
           conditions
    • Authors: Angela Dibenedetto; Maria Ventura, David Williamson, Francesco Lobefaro, Matthew D. Jones, Davide Mattia, Francesco Nocito, Michele Aresta
      Abstract: Sustainable chemical industry encompasses the shift from fossil carbon to renewable carbon. The synthesis of chemicals from non-edible biomass (cellulosic or oily) represents one of the key steps for "greening" the chemical industry. In this paper we report the aerobic oxidation-cleavage of C6 polyols (5-HMF, glucose, fructose, sucrose) in water to oxalic acid-OA (and succinic acid-SA) under mild conditions using M@CNT/NCNT (M=Fe, V; CNT=carbon nanotubes; NCNT= N-doped CNT), which, under suitable conditions, are recoverable and reusable without any loss of efficiency. The influence of temperature, PO2, reaction time, stirring rate are discussed and the best reaction conditions are emphasized for an almost complete conversion of the starting material, with a good yield of OA equal to 48%. SA and formic acid are the only co-products. The former can be further converted into OA by oxidation in presence of formic acid allowing to reach an overall yield of OA>62%. This process is clean and does not produce organic waste nor gas emissions.
      PubDate: 2018-01-16T06:32:04.085088-05:
      DOI: 10.1002/cssc.201702347
       
  • Polypropylene Nonwoven Fabric@Poly(ionic liquid)s for Switchable Oil/Water
           Separation, Dye Absorption and Antibacterial Applications
    • Authors: yongyuan ren; jiangna guo, dan xu, jing qin, qian lu, Feng Yan
      Abstract: Pollutants in wastewater include oils, dyes, and bacteria, making wastewater cleanup difficult. Here, we propose the preparation of multifunctional wastewater treatment media, poly(ionic liquid) grafted polypropylene (PP) nonwoven fabrics (PP@PIL), prepared via a simple and scalable surface grafting process. The fabricated PP@PIL fabrics exhibited superior switchable oil/water separation (η> 99%) and dye absorption performance (q = 410 mg/g), as well as high antibacterial properties. The oil/water separation could be easily switched via anion-exchanging of PIL segments. Moreover, the multiple functions (oil/water separation, dye absorption, and antibacterial properties) occurred at the same time, and did not interfere with each other. The multifunctional fibrous filter could be easily regenerated by washing with an acid solution, and the absorption capacity is maintained after many recycling tests. These promising features make PIL grafted PP nonwoven fabric a potential one-step treatment for multicomponent wastewater
      PubDate: 2018-01-15T05:54:12.831492-05:
      DOI: 10.1002/cssc.201702320
       
  • Photo-initiated Reduction of CO2 by H2 on Silica Surface
    • Authors: Chao Liu; Justin M. Notestein, Eric Weitz, Kimberly A. Gray
      Abstract: The reduction of CO2 is a promising route to produce valuable chemicals or fuels and create C-neutral resource cycles. Many different approaches to CO2 reduction have been investigated, but the ability of vacuum UV (VUV) irradiation to cleave C-O bonds has remained largely unexplored for use in processes that convert CO2 into useful products. Compared with other photo-driven CO2 conversion processes, here we demonstrate that VUV-initiated CO2 reduction can achieve much greater conversion under common photochemical reaction conditions when H2 and non-reducible oxides are present. Infrared spectroscopy provides evidence for a chain reaction initiated by VUV-induced CO2 splitting, which is enhanced in the presence of H2 and silica. When the reaction is carried out in the presence of silica or alumina surfaces, CO yields are increased and CH4 is formed as the only other detected product. CH4 production is not promoted by traditional photocatalysts such as TiO2 under these conditions. Assuming improvements in lamp and reactor efficiencies with scale up, or coupling with other available CO/CO2 hydrogenation techniques, these results reveal a potential, simple strategy by which CO2 could be valorized.
      PubDate: 2018-01-12T12:25:19.914081-05:
      DOI: 10.1002/cssc.201702341
       
  • Methanol-Water Aqueous Phase Reforming by the Assistant of Dehydrogenases
           at Near-Room Temperature
    • Authors: Yangbin Shen; Yulu Zhan, Shuping Li, Fandi Ning, Ying Du, Yunjie Huang, Ting He, Xiaochun Zhou
      Abstract: As an excellent hydrogen storage medium, methanol has many advantages, such as high hydrogen content (12.6 wt%), low-cost and availability from biomass or photocatalysis. However, conventional methanol-water reforming usually proceeds at high temperature. In this research, we successfully designed a new effective strategy to generate hydrogen from methanol at near-room temperature. The strategy involves two main procedures, which are CH3OHHCOOHH2 and NADHHCOOHH2. The first procedure (CH3OHHCOOHH2) is performed by alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and the Ir-catalyst. The second procedure (NADHHCOOHH2) is performed by formate dehydrogenase (FDH) and the Ir-catalyst. The Ir-catalyst is a reported polymer complex catalyst Cp*IrCl2(ppy), which owns high catalytic activity for formic acid decomposition at room temperature and compatibility to the enzymes, coenzyme and poisonous chemicals. This research reveals that the optimum hydrogen generation rate can reach up to 17.8 μmol h-1 g-1 under weak basic condition at 30 ℃. It will have high impact on hydrogen storage, production and applications, also provide a new inspiration for hydrogen generation from methanol.
      PubDate: 2018-01-11T21:55:44.42193-05:0
      DOI: 10.1002/cssc.201702359
       
  • Ultrathin Bismuth nanosheets as highly efficient electrocatalyst for CO2
           reduction
    • Authors: Panpan Su; Wenbin Xu, Yanling Qiu, Taotao Zhang, Xianfeng Li, Huamin Zhang
      Abstract: Electrochemical reducing CO2 to value-added products is an important and challenging reaction for sustainable energy study. In this study, bismuth nanosheets with thickness of ~10 nm were successfully prepared via electrochemical reduction of Bi3+. Ultrathin Bi nanosheets with numerous low-coordination sites can efficiently reduce CO2 to formate in aqueous solution. During the potential range of - 0.9 V to - 1.2 V vs RHE, the faradaic efficiency of formate is over 90%, which is one of the best reported Bi catalysts. At −0.7 V, the prepared Bi nanosheets exhibit much higher current for formate generation than that of bulk Bi, which is due to not only high surface area but also intrinsic electronic property change of ultrathin structure. Further, DFT calculation demonstrates that Bi nanosheets have the much higher electron state density around Fermi level than bulk counterpart, which favors the improvement of CO2 reduction on Bi nanosheets. At −1.0 V, Bi nanosheets exhibit high selectivity for formate and excellent stability during 5 hrs electrolysis measurement. The prepared Bi nanosheets with high activity and superior stability show great potential toward CO2 reduction area.
      PubDate: 2018-01-11T05:31:01.856408-05:
      DOI: 10.1002/cssc.201702229
       
  • Cellular Structure Fabricated on Ni Wire by a Simple and Cost-effective
           
    • Authors: Zhihong Wang; Fenhui Cao, Kongfa Chen, Yingming Yan, Yifu Chen, Yaohui Zhang, Xingbao Zhu, Bo Wei, Yueping Xiong, Zhe Lv
      Abstract: Cellular metals with the large surface-to-volume ratios and excellent electrical conductivity are widely applicable and have thus been studied extensively. It is highly desirable to develop a facile and cost-effective process for fabrication of porous metallic structures, more so for micron/nano pores. Herein, we propose a novel direct-flame strategy for in-situ fabrication of micron cellular architecture on Ni metal precursor. The flame provides required heat, but also serves as a fuel reformer providing a gas mixture of H2, CO and O2 for redox treatment of Ni metals. The redox processes at elevated temperatures allow a fast reconstruction of the metal, leading to cellular structure on Ni wire. This process is simple and clean, avoiding the use of sacrificial materials or templates. Further, nanocrystalline MnO2 is coated on the micron porous Ni wire (MPNW) to form a supercapacitor electrode. The MPNW-MnO2 electrode and the corresponding fiber-shaped supercapacitor exhibit high specific capacitance and excellent cycling stability. More importantly, this work provides a novel strategy for fabrication of cellular metals and alloys for a variety of applications, including catalysis, energy storage and conversion, and chemical sensing.
      PubDate: 2018-01-10T08:26:06.766362-05:
      DOI: 10.1002/cssc.201701886
       
  • Pt islands on 3D nut-like PtAg nanocrystals for efficient formic acid
           oxidation electrocatalysis
    • Authors: Hui Xu; Pingping Song, Bo Yan, Jin Wang, Caiqin Wang, Yukihide Shiraishi, Ping Yang, Yukou Du
      Abstract: Precise control of the structure offers a great opportunity to efficiently tune the catalytic performances of nanomaterials, enabling them enhancement in both activity and durability. We herein achieve a new class of Pt islands on 3D nut-like PtAg nanocrystals by exploiting the lower electronegativity of Ag and in conjunction with the galvanic replacement of catalytically active Pt to Ag tops. Those nanostructures with Pt nanoparticles coated, exposed facet, active surface composition enhance formic acid oxidation electrocatalysis with the optimized PtAg1 nuts achieved a factor of 4.0 and 2.4 in mass and specific activities (1728.3 mA mg-1 and 3.31 mA cm-2) relative to that of the commercial Pt/C (431.2 mA mg-1 and 1.41 mA cm-2), respectively. Moreover, such 3D PtAg1 nuts also display great enhancement in durability with less decay for at last 500 cycles, showing the great potential to serve as the promising catalysts for fuel cells and beyond. Our work provides a fundamental insight on the effect of morphology towards liquid fuel electrooxidation, which may pave a new way for the fabrication of highly efficient electrocatalysts for fuel cells.
      PubDate: 2018-01-09T07:20:44.14359-05:0
      DOI: 10.1002/cssc.201702409
       
  • Hybrid-organic-inorganic anatase as a bifunctional catalyst for enhanced
           production of HMF from glucose in water
    • Authors: Carlos A. S. Lanziano; Silvia F. Moya, Dean H. Barrett, Reginaldo Guirardello, Felipe de Souto da Silva, Roberto Rinaldi, Cristiane Barbieri Rodella
      Abstract: Herein, we report a synthetic route for the preparation of hybrid-organic-inorganic anatase (hybrid-TiO2) via a facile hydrothermal synthesis method employing citric acid. The synthetic approach results in a high surface area nanocrystalline anatase polymorph of TiO2. The uncalcined hybrid-TiO2 is directly studied here as the catalyst for the conversion of glucose into HMF. In the presence of the hybrid-TiO2, HMF yields up to 45% at glucose conversions up to 75% were achieved in water at 130 oC in a monophasic batch reactor. As identified by Ti K-edge XANES, hybrid-TiO2 contains a large fraction of five-fold coordinatively unsaturated Ti(IV) sites, which act as the Lewis acid catalyst for the conversion of glucose into fructose. As citric acid is anchored in the structure of hybrid-TiO2, carboxylate groups seem to catalyze the sequential conversion of fructose into HMF. The fate of citric acid bounded to anatase and the Ti(IV) Lewis acid sites throughout recycling experiments is also investigated. In a broader context, the contribution outlines the importance of hydrothermal synthesis for the creation of water-resistant Lewis acid sites for the conversion of sugars. Most importantly, the utilization of the hybrid-TiO2 with no calcination step contributes to dramatically decreasing the energy consumption in the catalyst preparation.
      PubDate: 2018-01-08T12:50:27.889026-05:
      DOI: 10.1002/cssc.201702354
       
  • A Perspective Review on the Materials and Mechanisms of Photo-Assisted
           Chemical Reactions under Light and Dark: Can it be called as Day-Night
           Photocatalysis'
    • Authors: Sakar Mohan; Nguyen Chinh-Chien, Vu Manh-Hiep, Trong-On Do
      Abstract: The photo-assisted catalytic reaction, conventionally known as photocatalysis, is blooming into the field of energy and environmental applications. It is widely known that the discovery of TiO2-assited photochemical reactions has led to achieve several unique applications such as degradation of pollutants in water and air, hydrogen production through water splitting, fuel conversion, cancer treatment, anti-bacterial activity, self-cleaning glasses and concrete, etc. These multifaceted applications of this phenomenon can be enriched and expanded further if this process is equipped with more tools and functions. The term 'photo'-assisted catalytic reactions clearly emphasizes that the photons are required to activate the catalyst, where this can be transcended even into dark if the electrons are stored in the material for the later use to continue the catalytic reactions in the absence of light. This can be achieved by equipping the photocatalyst with a so-called electron storage material as to break the present limitations in 'photo'-assisted catalytic reactions. In this context, this perspective article sheds lights on the materials and mechanism of the materials that perform photocatalytic reactions under light and dark conditions. The manifestation of such material systems could be an unparalleled technology in near future that would possibly make foot prints in all the sphere of the catalytic sciences.
      PubDate: 2018-01-08T10:20:23.258008-05:
      DOI: 10.1002/cssc.201702238
       
  • Fabrication of Cu2O-based Materials for Lithium-ion Batteries
    • Authors: Huan Pang; Qin Yuan Li, Li Zhang, Huai Guo Xue
      Abstract: The improvement of the performance of advanced batteries has played a key role in the energy research community since its inception. Therefore, it is necessary to explore excellent materials for applications in advanced batteries. Among the variety of materials applied in batteries, cuprous oxide and its composites stand out because of their specific characteristics (polymorphic forms, controllable structure, high cycling capacity, etc.). Thus, cuprous oxide and its composites will be fully introduced in this review for their applications in advanced batteries. It is believed that, in the future, both the study and the impact of cuprous oxide and its composites will be much more profound and lasting.
      PubDate: 2018-01-06T00:35:45.359507-05:
      DOI: 10.1002/cssc.201702325
       
  • Towards Sustainable Production of Formic Acid from Biomass for Getting
           Hydrogen and Fuels
    • Authors: Dmitri Bulushev; Julian R.H. Ross
      Abstract: Formic acid is a widely used commodity chemical. It can be used as a safe, easily handled and transported source of hydrogen or CO for different reactions including those producing fuels. The review includes historical aspects of formic acid production. It shortly analyzes the production based on traditional sources such as CO, methanol and methane. However, the main emphasis is done to the sustainable production of formic acid from biomass and biomass-derived products via hydrolysis, wet and catalytic oxidation processes. New strategies of low temperature synthesis from biomass may lead to utilization of formic acid for production of fuel additives such as methanol, upgraded bio-oil, gamma-valerolactone and its derivatives, as well as synthesis gas used for Fischer-Tropsch synthesis of hydrocarbons. Some technological aspects are considered.
      PubDate: 2018-01-06T00:35:41.121604-05:
      DOI: 10.1002/cssc.201702075
       
  • Bifunctional Pyridinium-Based Ionic liquid Immobilized
           [In2(dpa)3(1,10-phen)2]: Efficacy of Supported Ionic Liquid Phase Metal
           Organic Framework Catalyst for CO2 Fixation Reactions
    • Authors: Robin Babu; Jintu Francis Kurisingal, Jong-San Chang, Dae-Won Park
      Abstract: A pyridinium-based ionic liquid-decorated 1D MOF (IL-[In2(dpa)3(1,10-phen)2]) was developed as a bifunctional heterogeneous catalyst system for CO2-oxirane coupling reactions. An aqueous-microwave route was employed as competent with the hydrothermal pathway for the synthesis of [In2(dpa)3(1,10-phen)2] MOF, and the IL-[In2(dpa)3(1,10-phen)2] catalyst was synthesized using the covalent post functionalization method. Due to the synergetic effect of dual functional sites, including Lewis acid sites (coordinatively unsaturated indium sites) and I- ion in IL functional sites, IL-[In2(dpa)3(1,10-phen)2] displayed high catalytic activity for CO2-epoxide cycloaddition reactions under mild and solvent free conditions. Microwave pulses were employed for the first time for MOF-catalyzed CO2-epoxide cycloaddition reactions resulting in a high turnover frequency (TOF), ranging from 2000 to 3100 h-1. The catalyst had excellent reusability while maintaining continuous high selectivity. Furthermore, only a small amount of leaching was observed from the spent catalyst. A plausible reaction mechanism based on the synergistic effect of dual functional sites that effectively catalyze the CO2-epoxide cycloaddition reaction is proposed.
      PubDate: 2018-01-06T00:30:32.877678-05:
      DOI: 10.1002/cssc.201702193
       
  • A Co2P/WC Nano-Heterojunction Covered by N-Doped Carbon as High Efficient
           Electrocatalyst for Hydrogen Evolution Reaction
    • Authors: Yang-Guang Li; Ya Gao, Zhong-Ling Lang, Fei-Yang Yu, Hua-Qiao Tan, Gang Yan, Yong-Hui Wang, Yuan-Yuan Ma
      Abstract: Hydrogen evolution reaction (HER), which produces clean hydrogen through the electrochemical process, screams for more non-precious-metal electrocatalysts to lower the consumption of energy. Herein, we report a new Co2P/WC nano-heterojunction that consists of cobalt phosphide and tungsten carbide composite phases coated by few-layer N-doped graphitic carbon shells (abbr. Co2P/WC@NC). The composite was prepared by one-step annealing of the polyoxometalate Na9(NH4)5[{(B-α-PW9O34)Co3(OH) (H2O)2(Ale)}2Co]·35H2O (Co7P6W18) and dicyandiamide (DCA). Such preparation method realizes the simultaneous phosphorization for Co and carbonization for W in a confined space, so as to isolate a Co2P/WC nano-heterojunction phase for the first time. Co2P/WC @NC facilitates the hydrogen generation in the electrolysis process, which only needs a small overpotential of 91 mV to reach the current density of 10 mA cm-2 in the acid solution, which brings excellent HER performance, a fantastic Tafel slope (40 mV dec-1) and superior durability over a period of 50 h. Theoretical calculations show that the Co2P, WC, and NpyridinicC dopants in the material synergistically promoted the HER activity. Meanwhile, Co2P/WC@NC nano-heterojunction shows good HER performance in the whole pH range of electrolytes and considerable durability in acid media containing transition metal ions, which may attract more attention to the exploration and optimization of nano-heterojunction catalysts in HER.
      PubDate: 2018-01-02T08:22:07.206402-05:
      DOI: 10.1002/cssc.201702328
       
  • Front Cover: 2-(N-Methylbenzyl)pyridine: A Potential Liquid Organic
           Hydrogen Carrier with Fast H2 Release and Stable Activity in Consecutive
           Cycles (ChemSusChem 4/2018)
    • Authors: Jinho Oh; Kwanyong Jeong, Tae Wan Kim, Hyunguk Kwon, Jeong Woo Han, Ji Hoon Park, Young-Woong Suh
      Pages: 639 - 639
      Abstract: The Front Cover shows a representation of a H2 economy, based on production, storage, and utilization using our developed liquid organic hydrogen carrier (LOHC) material. H2 generated by solar-driven water splitting is loaded into the H2-lean LOHC by the hydrogenation reaction in a chemical plant and is then transported through the present energy transport infrastructures, for example, a tanker with a pressure-free vessel. The corresponding H2-rich material releases H2 very fast on the Pd surface at energy-demand sites including a H2 charging station for fuel cell electric vehicles (FCEVs). After H2 release, a tanker containing the H2-lean molecules goes back to the H2-supply sites for refueling. More information can be found in the Communication by Oh et al. on page 661 in Issue 4, 2018 (
      DOI : 10.1002/cssc.201702256).
      PubDate: 2018-02-22T04:05:29.359024-05:
       
  • 2-(N-Methylbenzyl)pyridine: A Potential Liquid Organic Hydrogen Carrier
           with Fast H2 Release and Stable Activity in Consecutive Cycles
    • Authors: Jinho Oh; Kwanyong Jeong, Tae Wan Kim, Hyunguk Kwon, Jeong Woo Han, Ji Hoon Park, Young-Woong Suh
      Pages: 641 - 641
      Abstract: Invited for this month's cover is the group of Prof. Young-Woong Suh at Hanyang University, in collaboration with Dr. Ji Hoon Park at Korea Research Institute of Chemical Technology and Prof. Jeong Woo Han at Pohang at University of Science and Technology. The Cover image is a representation of the H2 economy based on production, storage, and utilization for fuel cell electric vehicles, using our developed liquid organic hydrogen carrier (LOHC) material 2-(N-methylbenzyl)pyridine. The Communication itself is available at 10.1002/cssc.201702256.“The present energy transport infrastructures can be used…” 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.201702256. View the Front Cover here: 10.1002/cssc.201800167.
      PubDate: 2018-02-22T04:05:29.473508-05:
      DOI: 10.1002/cssc.201800168
       
  • Selective Hydrodeoxygenation of Alkyl Lactates to Alkyl Propionates with
           Fe-based Bimetallic Supported Catalysts
    • Authors: Santosh Govind Khokarale; Jian He, Leonhard Schill, Song Yang, Anders Riisager, Saravanamurugan Shunmugavel
      Abstract: Hydrodeoxygenation (HDO) of methyl lactate (ML) to methyl propionate (MP) were performed with various base metal supported catalysts. A high yield of 77% MP was obtained with bimetallic Fe-Ni/ZrO2 in methanol at 220 C at 50 bar H2. A synergic effect of Ni increased the yield of MP significantly when using Fe-Ni/ZrO2 instead of Fe/ZrO2 alone. Moreover, the ZrO2 support contributed to improve the yield as a phase transition of ZrO2 from tetragonal to monoclinic occurred after metal doping giving rise to fine dispersion of the Fe and Ni on the ZrO2, implying the higher catalytic activity of the material. Intriguingly, it was observed that Fe-Ni/ZrO2 also effectively catalyzed methanol reforming to produce in situ H2, followed by HDO of ML, yielding 60% MP at 220 C with 50 bar N2 instead of H2. Fe-Ni/ZrO2 also catalyzed HDO of other short chain alkyl lactates to the corresponding alkyl propionates in high yields around 70%. No loss of activity of Fe-Ni/ZrO2 occurred in five consecutive reaction runs demonstrating the high durability of the catalyst system.
      PubDate: 2017-12-29T09:25:30.361001-05:
      DOI: 10.1002/cssc.201702411
       
  • N-Annulated Perylene Based Hole-Transporters for Perovskite Solar Cells:
           the Significant Impacts of Lateral Substituents
    • Authors: Peng Wang; Yang Li, Rui Zhu, Junting Wang, Ze-Sheng Li, Niansheng Xu, Jidong Zhang
      Abstract: Perylene derivatives are a family of well-known organic electron-transporting materials with excellent photochemical and thermal stabilities, and have been widely used in various optoelectronic devices. In this work, two diphenylamine functionalized N-annulated perylenes are reported for the first time as a new class of hole-transporting materials (HTMs) for perovskite solar cells. With the aid of joint theoretical and experimental studies, we uncover that the HTM employing the methoxyphenyl lateral substituent features a closer stacking distance and a better aggregate connectivity in the solid film than the counterpart with the bulky 2-hexyldecyl lateral substituent, contributing to a higher hole mobility and a remarkably enhanced device performance of perovskite solar cells. This work demonstrates the significant influence of lateral substituents of HTMs on the intermolecular packing and solid microstructure, giving a clear clue on the molecular design of high performance organic semiconductors.
      PubDate: 2017-12-29T05:26:28.663552-05:
      DOI: 10.1002/cssc.201702379
       
  • Flower-like VS4/rGO Composite: an Energy Storage Material for Aluminum-ion
           Battery
    • Authors: Shuqiang Jiao; Shuai Wang, Jiguo Tu, Guohua Zhang, Shijie Li, Donghua Tian, Shuqiang Jiao
      Abstract: The flower-like VS4/rGO (reduced graphene oxide) composite was prepared by a typical hydrothermal method, which was investigated as cathode for aluminum-ion battery with non-inflammable and non-explosive ionic liquid electrolytes. The charge/discharge performance measurements were carried out in a voltage range of 0.1~2.0 V vs. Al/AlCl4-, which suggests the initial charge/discharge specific capacity approaching 491.57 and 406.94 mA h g-1, respectively, at a current density of 100 mA g-1. Additionally, in the cycling performance, discharge capacity has been observed to remain over 80, 70 and 60 mA h g-1 at current densities of 100, 200 and 300 mA g-1 after 100 cycles, respectively. The results of coulombic efficiency over 90% after 100 cycles and high capacity retained indicate a favorable cathode material for novel rechargeable aluminum-ion battery.
      PubDate: 2017-12-29T03:55:28.625288-05:
      DOI: 10.1002/cssc.201702270
       
  • Hydrothermally induced O-doping and porous structure of graphitic carbon
           nitride with highly ordered architecture and dramatically enhanced
           photocatalytic property
    • Authors: Chao Wang; Huiqing Fan, Xiaohu Ren, Jiangwei Ma, Jiawen Fang, Weijia Wang
      Abstract: As an amorphous or semi-crystalline material, graphitic carbon nitride (g-C3N4) displays poor photocatalytic activity due to the rapid recombination of photo generated charge carriers, which is mainly caused by the high density of defects in the graphitic structure. In this work, a porous O-doped g-C3N4 nanosheet (P-CNO) with highly ordered architecture is fabricated by introducing a novel hydrothermal treatment to the precursor before the final thermal condensation. The photocatalytic hydrogen evolution rate (HER) and HER per surface area of P-CNO are 13.9 times and 1.7 times higher than that of bulk g-C3N4. The improved photocatalytic activity is ascribed to the synergistic effect of O-doping, porous sheet-like morphology and increased crystallinity. This work also provides a new approach for synthesis of other polymer-based photocatalysts with high crystallinity and excellent performances.
      PubDate: 2017-12-29T02:25:51.341178-05:
      DOI: 10.1002/cssc.201702278
       
  • Polyethylene Glycol-[60]fullerene-based Materials for Perovskite Solar
           Cells with Improved Moisture Resistance and Reduced Hysteresis
    • Authors: Juan L. Delgado; Silvia Collavini, michael saliba, wolfgang tress, philippe holzhey, sebastian voelker, konrad domanski, silver turren-cruz, amita ummadisingu, shaik zakeeruddin, anders hagfeld, Michael Graetzel
      Abstract: A series of [60]fullerenes covalently functionalized with the polyethylene glycol polymer (PEG) is presented. These novel [60]fullerene-based materials have been incorporated as additives in CH3NH3PbI3 (MAPbI3), the most common organic-inorganic perovskite used in perovskite solar cells. The extensive photovoltaic study performed using these materials shows beneficial effects on the performance of these cells, reducing hysteresis and increasing stability against moisture, thereby retaining up to 97% of their initial power conversion efficiency at ambient atmosphere.
      PubDate: 2017-12-28T21:55:34.721041-05:
      DOI: 10.1002/cssc.201702265
       
  • A strategy to boost H2 generation ability of MOFs—inside-outside
           decoration for the separation of electron and holes
    • Authors: Yang Wang; Lianjie Ling, Wei Zhang, Kejian Ding, Yu Yu, Wubiao Duan, Bo Liu
      Abstract: Inhibiting the recombination of electron and holes plays an essential role in photocatalytic process, particularly for MOFs which had long been expected as high efficient photocatalysts. Herein, we introduce a new strategy to make efficient separation of electron and holes for MOFs-based photocatalyst, UiO-66-NH2. At first, encapsulate Pt NPs into UiO-66-NH2 (Pt@U6N) to shorten the electrons transport distance inside, then using graphene oxide to wrap the external surface of Pt@U6N to felicitate the superficial electrons transfer. The designed structure was found possess superior H2 generation ability than sole inside/outside decoration, highlighting the enhanced property strongly correlates with the inhibited recombination of electron and holes by the inside-outside modification strategy. These findings suggest a synergistic effect of Pt NPs and graphene oxide on UiO-66-NH2 and revealed a new modification strategy to enhance the photocatalytic activity for photocatalysts.
      PubDate: 2017-12-28T06:56:05.75368-05:0
      DOI: 10.1002/cssc.201702316
       
  • A potential liquid organic hydrogen carrier: 2-(n-methylbenzyl)pyridine
           with fast H2 release and stable activity in consecutive
           hydrogenation-dehydrogenation cycles
    • Authors: Jinho Oh; Kwanyong Jeong, Tae Wan Kim, Hyunguk Kwon, Jeong Woo Han, Ji Hoon Park, Young-Woong Suh
      Abstract: For H₂ storage based on reversible hydrogenation and dehydrogenation of a liquid organic hydrogen carrier (LOHC), we herein demonstrate a potential of 2-(n-methylbenzyl)pyridine (MBP) with the H₂ storage density of 6.15 wt%. This material and the corresponding perhydro product (H12-MBP) exist in liquid state at room temperature. Remarkably, H₂ release is much faster from H12-MBP over Pd/C than from the benchmark perhydro benzyltoluene over Pt/C at lower temperatures than 270 °C due to the addition of N atom into the benzene ring. Since this positive effect is unfavorable to the hydrogenation reaction, more Ru/Al₂O₃ catalyst or prolonged reaction time would be applied for complete H₂ storage. Experiments for repeated hydrogenation/dehydrogenation cycles reveal that reversible H₂ storage and release are possible without degradation of the pair MBP/H12-MBP. The prepared MBP satisfies the requirements in chemical stability, handling properties, and cytotoxicity test.
      PubDate: 2017-12-28T02:01:46.232327-05:
      DOI: 10.1002/cssc.201702256
       
  • Connection between Lithium Coordination and Lithium Diffusion in
           Pyr12O1FTFSI Ionic Liquid Electrolytes
    • Authors: Guinevere Giffin; Arianna Moretti, Sangsik Jeong, Kartik Pilar, Marc Brinkkoetter, Steve Greenbaum, Monika Schoenhoff, Stefano Passerini
      Abstract: The use of highly concentrated ionic liquid-based electrolytes results in improved rate capability and capacity retention at 20°C, as compared to Li+-dilute systems, in Li-metal and Li-ion cells. This work explores the connection between the bulk electrolyte properties and the molecular organization to give insight into the concentration dependence of the Li+ transport mechanisms. Below 30 mol%, the Li+-containing species are primarily smaller complexes (one Li+ cation) and the Li+ ion transport is mostly derived from the vehicular transport. Above 30%, where the viscosity is substantially higher and the conductivity lower, the Li+-containing species are a mix of small and large complexes (one and more than one Li+ cation, respectively). The overall conduction mechanism likely changes to favor structural diffusion via the exchange of anions in the first Li+ solvation shell. The good rate performance is likely directly influenced by the presence of the larger Li+ complexes, which promote Li+-ion transport (as opposed to Li+-complex transport) and increase the Li+ availability at the electrode.
      PubDate: 2017-12-27T21:55:30.764544-05:
      DOI: 10.1002/cssc.201702288
       
  • One-step Synthesis of Nb2O5/C/Nb2C (MXene) Composites and Their Use as
           Photocatalysts for Hydrogen Evolution
    • Authors: Tongming Su; Rui Peng, Zachary D. Hood, Michael Naguib, Ilia N. Ivanov, Jong Kahk Keum, Zuzeng Qin, Zhanhu Guo, Zili Wu
      Abstract: : Hydrogen production through facile photocatalytic water splitting is regarded as a promising strategy for solving global energy problems. Transition metal carbides (MXenes) have recently drawn attention as potential co-catalyst candidates for photocatalysts. Here, we report niobium pentoxide/carbon/niobium carbide (MXene) hybrid materials (Nb2O5/C/Nb2C) as photocatalysts for hydrogen evolution from water splitting. The Nb2O5/C/Nb2C composites were synthesized by a one-step CO2 oxidation of Nb2CTx. Nb2O5 grew homogeneously on Nb2C after mild oxidation during which some amorphous carbon also formed. With an optimized oxidation time of 1.0 h, the Nb2O5/C/Nb2C shows the highest hydrogen generation rate (7.81 μmol*h-1gcat-1), which is 4 times as high as that of pure Nb2O5. The enhanced performance of Nb2O5/C/Nb2C can be attributed to the intimate contact between the Nb2O5 and the conductive Nb2C, and the separation of photogenerated charge carriers at the Nb2O5/Nb2C interface, showing the promise of transition metal carbide as co-catalysts for photocatalytic hydrogen production.
      PubDate: 2017-12-27T12:50:24.185119-05:
      DOI: 10.1002/cssc.201702317
       
  • Novel Starbon/HACS-supported N-heterocyclic carbene-iron(III) catalyst for
           efficient conversion of fructose to HMF
    • Authors: Avtar Singh Matharu; Suleiman Ahmed, Badriya Al-Monthery, Duncan Macquarrie, Yoon-Sik Lee, Yohan Kim
      Abstract: : Iron-nitrogen heterocyclic carbenes (Fe-NHCs) have come to the fore because of their ability to be employed in diverse catalytic applications ranging from C-C cross-coupling and C-X bond formation to substitution, reduction, polymerization, and dehydration. The detailed synthesis, characterisation and application of novel heterogeneous Fe-NHC catalysts immobilised on mesoporous expanded starch and Starbon™ 350 for facile fructose to HMF conversion is reported. Both catalyst types showed good performance for the dehydration of fructose to HMF when the reaction was explored at 100 ◦C and varying time (10 min, 20 min, 0.5 h, 1 h, 3 h and 6 h): Fe-NHC S350, highest HMF yield, 81.7 % (t=0.5 h), TOF=169 h-1, fructose conversion of 95 % and HMF selectivity of 85.7 %, and; Fe-NHC expanded HACS, highest yield, 86 % (t=0.5 h), TOF=206 h-1, fructose conversion of 87 % and HMF selectivity of 99 %. An iron-loading of 0.26 and 0.30 mmol/g was achieved for the Fe-NHC expanded starch and Fe-NHC Star-bon™ 350, respectively.
      PubDate: 2017-12-27T09:25:37.991062-05:
      DOI: 10.1002/cssc.201702207
       
  • Rapid Formation of a Disordered Layer on Monoclinic BiVO4:
           Co-catalyst-free Photoelectrochemical Solar Water Splitting
    • Authors: Jung Kyu Kim; Yoonjun Cho, Myung Jin Jeong, Ben Levy-Wendt, Dongguen Shin, Yeonjin Yi, Dong Hwan Wang, Xiaolin Zheng, Jong Hyeok Park
      Abstract: Surface disordered layer is plausible approach to improve the photoelectrochemical performance of TiO2. However, the formation of a crystal disordered layer in BiVO4 and its effectiveness towards photoelectrochemical water splitting has remained a big challenge. Here, we report a rapid solution process (within 5 seconds) that is capable of forming a few nanometre-thick disordered layer on the surface of BiVO4 nanoparticles using a specific solution with controllable reducing power. The disordered layer on BiVO4 alleviates charge recombination at the electrode/electrolyte interface and greatly reduces the on-set potential, which in turn results in a photocurrent density of around 2.3 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE). This value is 2.1 times higher than that of bare BiVO4. The enhanced photoactivity is attributed to the increased charge separation and transfer efficiencies, which provide an effective avenue for resolving an intrinsic drawback of bare BiVO4 such as short hole diffusion length of around 100 nm and poor surface oxygen evolution reactivity.
      PubDate: 2017-12-23T12:10:31.623374-05:
      DOI: 10.1002/cssc.201702173
       
  • Acid-catalysed conversion of carbohydrates into value added small
           molecules in aqueous media and ionic liquids
    • Authors: Iurii Bodachivskyi; Unnikrishnan Kuzhiumparambil, D. Bradley Glen Williams
      Abstract: Biomass is the only realistic major alternative source (to crude oil) of hydrocarbon substrates for the commercial synthesis of bulk and fine chemicals. Within biomass, terrestrial sources are the most accessible, and therein lignocellulosic materials are most abundant. While lignin shows promise for the delivery of certain types of organic molecules, cellulose is a biopolymer with significant potential for conversion into high volume and high value chemicals. This review covers the acid-catalysed conversion of lower value (poly)carbohydrates into valorised organic building block chemicals (platform molecules). It focuses on those conversions performed in aqueous media or ionic liquids. It does this to provide the reader with a perspective on what can be considered a best case scenario, i.e. that the overall process is as sustainable as possible.
      PubDate: 2017-12-17T21:51:08.243794-05:
      DOI: 10.1002/cssc.201702016
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
  • 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
       
 
 
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