for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> MATHEMATICS (Total: 864 journals)
    - APPLIED MATHEMATICS (68 journals)
    - GEOMETRY AND TOPOLOGY (19 journals)
    - MATHEMATICS (643 journals)
    - MATHEMATICS (GENERAL) (40 journals)
    - NUMERICAL ANALYSIS (19 journals)
    - PROBABILITIES AND MATH STATISTICS (75 journals)

MATHEMATICS (643 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 3)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2)
Academic Voices : A Multidisciplinary Journal     Open Access   (Followers: 2)
Accounting Perspectives     Full-text available via subscription   (Followers: 6)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 20)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 10)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 4)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Decision Sciences     Open Access   (Followers: 4)
Advances in Difference Equations     Open Access   (Followers: 1)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 1)
Advances in Materials Sciences     Open Access   (Followers: 15)
Advances in Mathematical Physics     Open Access   (Followers: 6)
Advances in Mathematics     Full-text available via subscription   (Followers: 10)
Advances in Numerical Analysis     Open Access   (Followers: 3)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Pure and Applied Mathematics     Hybrid Journal   (Followers: 5)
Advances in Pure Mathematics     Open Access   (Followers: 4)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2)
African Journal of Educational Studies in Mathematics and Sciences     Full-text available via subscription   (Followers: 5)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Afrika Matematika     Hybrid Journal   (Followers: 1)
Air, Soil & Water Research     Open Access   (Followers: 7)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 2)
Algebra Colloquium     Hybrid Journal   (Followers: 4)
Algebra Universalis     Hybrid Journal   (Followers: 2)
Algorithmic Operations Research     Full-text available via subscription   (Followers: 5)
Algorithms     Open Access   (Followers: 9)
Algorithms Research     Open Access  
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Mathematical Analysis     Open Access  
American Journal of Mathematics     Full-text available via subscription   (Followers: 7)
American Journal of Operations Research     Open Access   (Followers: 5)
American Mathematical Monthly     Full-text available via subscription   (Followers: 6)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 7)
Analele Universitatii Ovidius Constanta - Seria Matematica     Open Access   (Followers: 1)
Analysis     Hybrid Journal   (Followers: 2)
Analysis and Applications     Hybrid Journal   (Followers: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 4)
Analysis Mathematica     Full-text available via subscription  
Annales Mathematicae Silesianae     Open Access  
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annales UMCS, Mathematica     Open Access   (Followers: 1)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica     Open Access  
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Discrete Mathematics     Full-text available via subscription   (Followers: 6)
Annals of Mathematics     Full-text available via subscription  
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of the Alexandru Ioan Cuza University - Mathematics     Open Access  
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1)
Annals of West University of Timisoara - Mathematics     Open Access  
Annuaire du Collège de France     Open Access   (Followers: 5)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applications of Mathematics     Hybrid Journal   (Followers: 1)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Mathematics     Open Access   (Followers: 3)
Applied Mathematics     Open Access   (Followers: 4)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4)
Applied Mathematics - A Journal of Chinese Universities     Hybrid Journal  
Applied Mathematics Letters     Full-text available via subscription   (Followers: 1)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1)
Applied Numerical Analysis & Computational Mathematics     Hybrid Journal   (Followers: 5)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 2)
Arabian Journal of Mathematics     Open Access   (Followers: 2)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 17)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Journal of Algebra     Open Access   (Followers: 1)
Asian Journal of Current Engineering & Maths     Open Access  
Asian-European Journal of Mathematics     Hybrid Journal   (Followers: 2)
Australian Mathematics Teacher, The     Full-text available via subscription   (Followers: 6)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 1)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access  
Baltic International Yearbook of Cognition, Logic and Communication     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
BIBECHANA     Open Access  
BIT Numerical Mathematics     Hybrid Journal  
BoEM - Boletim online de Educação Matemática     Open Access  
Boletim Cearense de Educação e História da Matemática     Open Access  
Boletim de Educação Matemática     Open Access  
Boletín de la Sociedad Matemática Mexicana     Hybrid Journal  
Bollettino dell'Unione Matematica Italiana     Full-text available via subscription   (Followers: 1)
British Journal of Mathematical and Statistical Psychology     Full-text available via subscription   (Followers: 19)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 5)
Bulletin des Sciences Mathamatiques     Full-text available via subscription   (Followers: 4)
Bulletin of Dnipropetrovsk University. Series : Communications in Mathematical Modeling and Differential Equations Theory     Open Access   (Followers: 1)
Bulletin of Mathematical Sciences     Open Access   (Followers: 2)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3)
Bulletin of the Malaysian Mathematical Sciences Society     Hybrid Journal  
Calculus of Variations and Partial Differential Equations     Hybrid Journal  
Canadian Journal of Science, Mathematics and Technology Education     Hybrid Journal   (Followers: 18)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CAUCHY     Open Access   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
CHANCE     Hybrid Journal   (Followers: 5)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
ChemSusChem     Hybrid Journal   (Followers: 7)
Chinese Annals of Mathematics, Series B     Hybrid Journal  
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Mathematics     Open Access  
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Cogent Mathematics     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Collectanea Mathematica     Hybrid Journal  
College Mathematics Journal     Full-text available via subscription   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 1)
Communications On Pure & Applied Mathematics     Hybrid Journal   (Followers: 3)
Complex Analysis and its Synergies     Open Access   (Followers: 2)
Complex Variables and Elliptic Equations: An International Journal     Hybrid Journal  
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Comptes Rendus Mathematique     Full-text available via subscription   (Followers: 1)
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 Complexity     Hybrid Journal   (Followers: 4)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Concrete Operators     Open Access   (Followers: 4)
Confluentes Mathematici     Hybrid Journal  
COSMOS     Hybrid Journal  
Cryptography and Communications     Hybrid Journal   (Followers: 12)
Cuadernos de Investigación y Formación en Educación Matemática     Open Access  
Cubo. A Mathematical Journal     Open Access  
Czechoslovak Mathematical Journal     Hybrid Journal   (Followers: 1)
Demographic Research     Open Access   (Followers: 11)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 28)
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Dhaka University Journal of Science     Open Access  
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 2)
Discrete Mathematics     Hybrid Journal   (Followers: 7)
Discrete Mathematics & Theoretical Computer Science     Open Access  
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Doklady Mathematics     Hybrid Journal  
Duke Mathematical Journal     Full-text available via subscription   (Followers: 1)
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Electronic Journal of Graph Theory and Applications     Open Access   (Followers: 2)
Electronic Notes in Discrete Mathematics     Full-text available via subscription   (Followers: 2)
Elemente der Mathematik     Full-text available via subscription   (Followers: 3)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Ensino da Matemática em Debate     Open Access  
Entropy     Open Access   (Followers: 4)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription   (Followers: 1)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 4)
European Journal of Mathematics     Hybrid Journal   (Followers: 1)
European Scientific Journal     Open Access   (Followers: 2)
Experimental Mathematics     Hybrid Journal   (Followers: 3)
Expositiones Mathematicae     Hybrid Journal   (Followers: 2)
Facta Universitatis, Series : Mathematics and Informatics     Open Access  
Fasciculi Mathematici     Open Access  
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fixed Point Theory and Applications     Open Access   (Followers: 1)
Formalized Mathematics     Open Access   (Followers: 2)

        1 2 3 4 | 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  [1616 journals]
  • Determination of conduction and valence band electronic structure of
           LaTiOxNy thin film
    • Authors: Markus Pichler; Jakub Szlachetko, Ivano Eligio Castelli, Nicola Marzari, Max Döbeli, Alexander Wokaun, Daniele Pergolesi, Thomas Lippert
      Abstract: The nitrogen substitution into the oxygen sites of several oxide materials leads to a reduction of the band gap to the visible light energy range, which makes these oxynitride semiconductors potential photocatalysts for efficient solar water splitting. Oxynitrides typically show a different crystal structure compare to the pristine oxide material. Since the band gap is correlated to both the chemical composition and the crystal structure, it is not trivial to distinguish what modifications of the electronic structure induced by the nitrogen substitution are related to compositional and/or structural effects. Here, X-ray emission and absorption spectroscopy is used to investigate the electronic structures of orthorhombic perovskite LaTiOxNy thin films in comparison with films of the pristine oxide LaTiOx with similar orthorhombic structure and cationic oxidation state. Experiment and theory show the expected upward shift in energy of the valence band maximum that reduces the band gap as a consequence of the nitrogen incorporation. But this study also shows that the conduction band minimum, typically considered almost unaffected by the nitrogen substitution, undergoes a significant downward shift in energy. For a rational design of oxynitride photocatalysts the observed changes of both the unoccupied and occupied electronic states have to be taken into account to justify the total band gap narrowing induced by the nitrogen incorporation.
      PubDate: 2017-03-23T04:25:41.874609-05:
      DOI: 10.1002/cssc.201601632
       
  • Electrochemistry for the generation of renewable chemicals: One-pot
           electrochemical deoxygenation of xylose to δ-valerolactone
    • Authors: Olusola Oladele James; Waldemer Sauter, Uwe Schröder
      Abstract: In this study, we demonstrate the electrochemical conversion of xylose to δ-valerolactone via carbonyl intermediates. The conversion was achieved in aqueous media and at ambient conditions. This study also demonstrates that feedstocks for the use of electrochemistry for production of renewable chemicals and biofuels can be extended to primary carbohydrate molecules. This is the first report on a one-pot electrochemical deoxygenation of xylose to δ-valerolactone.
      PubDate: 2017-03-22T23:25:27.238523-05:
      DOI: 10.1002/cssc.201700209
       
  • An Efficient and Reusable Embedded Ru Catalyst for the Hydrogenolysis of
           Levulinic Acid to γ-Valerolactone
    • Authors: Zuojun Wei; Jiongtao Lou, Chuanmin Su, Dechao Guo, Yingxin Liu, Shuguang Deng
      Abstract: To achieve a higher activity and reusability of a Ru-based catalyst, Ru nanoparticles were embedded in N-doped mesoporous carbon through a hard-template method. The catalyst showed excellent catalytic performance (314 h−1 turnover frequency) and recyclability (reusable five times with 3 % activity loss) for the hydrogenolysis of levulinic acid to γ-valerolactone. Compared with the mesoporous carbon without N-doping and conventional activated carbon, the introduction of N-dopant effectively improved the dispersion of Ru nanoparticles, decreased the average size of Ru nanoparticles to as small as 1.32 nm, and improved the adsorption of levulinic acid, which contributed to the increase in the activity of the catalyst. Additionally, the embedding method increased the interaction between Ru nanoparticles and carbon support in contrast with the conventional impregnation method, thus preventing the Ru nanoparticles from migration, aggregation, and leaching from the carbon surface and therefore increasing the reusability of the catalyst.Stability through doping: The embedding of Ru nanoparticles in N-doped mesoporous carbon effectively improve the dispersion and decrease the average size of the Ru nanoparticles, improve the adsorption of levulinic acid, and increase the interaction between Ru and the support. The strategy prevents the Ru nanoparticles from migration, aggregation, and leaching, and consequently increases the reusability of the catalyst.
      PubDate: 2017-03-22T07:27:24.705322-05:
      DOI: 10.1002/cssc.201601769
       
  • Rational Engineering of BODIPY-bridged-Trisindole derivatives for Solar
           Cell Applications
    • Authors: Nicolas Leclerc; Ibrahim Bulut, Quentin Huaulmé, Antoine Mirloup, Patricia Chávez, Sadiara Fall, Anne Hébraud, Stéphane Méry, Benoit Heinrich, Thomas Heiser, Patrick Lévêque
      Abstract: Boron dipyrromethene (Bodipy) are known to be efficient photon harvesting chromophores. However, their study as active materials in bulk heterojunction (BHJ) solar cells is still scarce. In this paper, we developed new synthetic ways to design original Bodipy-based dumbbell-shape molecules, including a first 2,3,5,6-tetravinyl aromatic Bodipy molecule. We demonstrated that high fill factors can be obtained in BHJ solar cells when blended with a fullerene derivative, leading to a new Bodipy-based record power conversion efficiency of 5.8%.
      PubDate: 2017-03-21T22:32:14.659272-05:
      DOI: 10.1002/cssc.201700465
       
  • Metal-Organic Framework-Templated Catalyst: Synergy in Multiple Sites for
           Catalytic CO2 Fixation
    • Authors: Hai-Long Jiang; Meili Ding, Si Chen, Xiao-Qin Liu, Lin-Bing Sun, Junling Lu
      Abstract: The types and quantities of active sites play critical roles in catalysis. Herein, ZnO nanoparticles encapsulated N-doped porous carbon has been rationally prepared by the pyrolysis of a metal-organic framework (MOF) followed by moderate oxidation treatment. The resultant catalyst exhibits excellent activity, selectivity and recyclability in the CO2 cycloaddtion reactions with epoxides, due to the synergy of multiple sites inherited from the MOF and generated by the oxidation process.
      PubDate: 2017-03-21T05:20:58.370481-05:
      DOI: 10.1002/cssc.201700245
       
  • Efficient Hydrogen Storage and Production Using a Catalyst with an
           Imidazoline-Based, Proton-Responsive Ligand
    • Authors: Lin Wang; Naoya Onishi, Kazuhisa Murata, Takuji Hirose, James T. Muckerman, Etsuko Fujita, Yuichiro Himeda
      Abstract: The Inside Cover picture shows a promising H2 storage system in water under very mild conditions. As we all know, green plants convert CO2 to sugar for energy storage through photosynthesis, which can also release CO2 by respiration. Thus, by mimicking nature, we report a new homogeneous iridium catalyst with a proton-responsive ligand that uses CO2 and H2 to store energy efficiently in formic acid and releases them by employing the same catalyst in aqueous media without the need of organic additives/solvents. More details can be found in the Communication by Wang et al. (
      DOI : 10.1002/cssc.201601437).
      PubDate: 2017-03-21T04:21:46.430489-05:
       
  • CO2 Catalysis
    • Authors: Arjan W. Kleij; Michael North, Atsushi Urakawa
      Abstract: The Cover picture shows how CO2 is recycled in nature by using the concept of photosynthesis. Owing to human activities, the carbon cycle has become unbalanced and atmospheric CO2 levels are continuously rising. Currently, scientists are increasingly studying ways to convert anthropogenic CO2 into useful products, such as fuels and fine chemical intermediates, to offer new technologies for potential mitigation of CO2 emissions and new valorization potential. The aim of this Special Issue is to highlight recent work that illustrates the importance of catalysis as a key enabling technology for CO2 conversion. More details can be found in the Editorial by Guest Editors Kleij, North, and Urakawa. (
      DOI : 10.1002/cssc.201700218).
      PubDate: 2017-03-21T04:21:39.992944-05:
       
  • Aqueous Biphasic Systems for the Synthesis of Formates by Catalytic CO2
           Hydrogenation: Integrated Reaction and Catalyst Separation for
           CO2-Scrubbing Solutions
    • Authors: Martin Scott; Beatriz Blas Molinos, Christian Westhues, Giancarlo Franciò, Walter Leitner
      Abstract: The Inside Back Cover picture shows the direct hydrogenation of CO2saturated aqueous scrubbing solutions to formate adducts in a biphasic system using a ruthenium catalyst. More details can be found in the Full Paper by Scott et al. (
      DOI : 10.1002/cssc.201601814).
      PubDate: 2017-03-21T04:21:25.335069-05:
       
  • One-electron Initiated Two-electron Oxidation of Water by Aluminum
           Porphyrins with Earth's Most Abundant Metal Ion
    • Authors: Fazalurahman Kuttassery; Siby Mathew, Shogo Sagawa, Sebastian Nybin Remello, Arun Thomas, Daisuke Yamamoto, Satomi Onuki, Yu Nabetani, Hiroshi Tachibana, Haruo Inoue
      Abstract: We report here a new molecular catalyst for efficient water splitting, aluminum porphyrins (tetra-methylpyridiniumylporphyrinatealuminum: AlTMPyP), containing the Earth's most abundant metal as the central ion. One-electron oxidation of the aluminum porphyrin initiates the two-electron oxidation of water to form hydrogen peroxide as the primary reaction product with the lowest known overpotential (97 mV). The aluminum-peroxo complex was clearly detected by a cold-spray ionization mass-spectrometry in HRMS mode and the structure of the intermediate was further confirmed using laser-Raman spectroscopy, indicating the hydroperoxy complex of AlTMPyP to be the key intermediate in the reaction. The two-electron oxidation of water to form hydrogen peroxide was essentially quantitative, with a Faradaic efficiency of 99%. The catalytic reaction was found to be highly efficient, with a turnover frequency up to ~ 2 × 10⁴ s¯¹. A reaction mechanism is proposed involving oxygen-oxygen bond formation by the attack of a hydroxide ion on the oxyl-radical-like axial ligand oxygen atom in the one-electron-oxidized form of AlTMPyP(O¯)₂, followed by a second electron transfer to the electrode.
      PubDate: 2017-03-20T23:26:09.667587-05:
      DOI: 10.1002/cssc.201700322
       
  • A Nitrogen-Doped Carbon Catalyst for Electrochemical CO2 Conversion to CO
           with High Selectivity and Current Density
    • Authors: Huei-Ru Molly Jhong; Claire E. Tornow, Bretislav Smid, Andrew A. Gewirth, Stephen M. Lyth, Paul J. A. Kenis
      Abstract: The Back Cover picture shows the electrochemical conversion of carbon dioxide to carbon monoxide and water, over a non-precious nitrogen-doped carbon catalyst. More details can be found in the Full Paper by Jhong et al. (
      DOI : 10.1002/cssc.201600843).
      PubDate: 2017-03-20T09:35:29.571667-05:
       
  • Designing Squaraines to Control Charge Injection and Recombination
           Processes in NiO-based Dye-Sensitized Solar Cells
    • Authors: Oliver Langmar; Davide Saccone, Anna Amat, Simona Fantacci, Guido Viscardi, Claudia Barolo, Ruben Costa, Dirk Michael Guldi
      Abstract: Herein, the synthesis of a novel family of squaraines (SQ) and their application in p-type dye-sensitized solar cells (DSSC) is presented. In particular, two sets of SQs were designed. The SQs have been characterized by using a joint theoretical, photophysical and electrochemical approach. Importantly, the presence of different central groups forces them into a frozen cis (dicyanovinyl group) or a trans (oxygen group) conformation. Based on the latter, the current work enables the direct comparison between cis and trans isomers, as well as the impact of a different number of anchors. Considering their electron accepting and light harvesting character they were tested in NiO-based DSSCs. Photocurrent-voltage, incident photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements were performed. By virtue of their different symmetry, stereochemistry, and number of carboxylic groups, altered adsorption behavior onto NiO electrodes, as well as diverse charge injection and charge recombination dynamics were noted under operation conditions. SQs with four linkers show the best balance between charge injection and recombination.. As a complement, we assembled tandem-DSSCs featuring SQ / NiO photocathodes and N719 / TiO2 photoanodes. The IPCE of the resulting tandem-DSSCs imply light harvesting throughout most of the visible part of the solar spectrum due to the complementary absorption of SQ and N719.
      PubDate: 2017-03-20T06:21:06.06418-05:0
      DOI: 10.1002/cssc.201700152
       
  • Eco-efficient synthesis of highly-porous CoCO3 anodes for Li+ and Na+
           storage using supercritical CO2 precursors
    • Authors: Hui-Ying Li; Chuan-Ming Tseng, Cheng-Hsien Yang, Tai-Chou Lee, Ching-Yuan Su, Chien-Te Hsieh, Jeng-Kuei Chang
      Abstract: An eco-efficient synthesis route of high-performance carbonate anodes for Li+ and Na+ batteries is developed. With supercritical CO2 (SCCO2) as the precursor, which has gas-like diffusivity, extremely low viscosity, and near-zero surface tension, CoCO3 particles are uniformly formed and tightly connected on graphene nanosheets (GNSs). This synthesis can be conducted at 50 °C, which is considerably lower than the temperature required for conventional preparation methods, minimizing energy consumption. The obtained CoCO3 particles (~20 nm in diameter), which have a unique interpenetrating porous structure, can increase the number of electroactive sites, promote electrolyte accessibility, shorten ion diffusion length, and readily accommodate the strain generated upon charging/discharging. With a reversible capacity of 1105 mAh g−1, the proposed CoCO3/GNS anode shows an excellent rate capability, as it is able to deliver 745 mAh g−1 in 7.5 min. More than 98% of the initial capacity can be retained after 200 cycles. These properties are clearly superior to those of previously reported CoCO3-based electrodes for Li+ storage, indicating the merit of our SCCO2 synthesis, which is facile, green, and easily scaled up for mass production.
      PubDate: 2017-03-20T04:20:43.663523-05:
      DOI: 10.1002/cssc.201700171
       
  • Enhanced surface charge transport and stability of CdS/1D Zr:Fe2O3 nanorod
           arrays with Al2O3 passivation layer for photoelectrochemical solar
           hydrogen generation
    • Authors: Jum Suk Jang; Mahadeo A Mahadik, Arunprabaharan Subramanian, Min Cho, Hee-Suk Chung
      Abstract: CdS sensitized 1D Zr:Fe2O3 nanorod arrays have been synthesized on fluorine-doped tin oxide substrates via a two-step hydrothermal method. The photoelectrochemical results demonstrate that the current density (4.2 mA.cm-2 at 0 V (vs. Ag/AgCl) recorded under illumination for the CdS/1D Zr:Fe2O3 photoanodes is 2.8 time higher than the bare 1D Zr:Fe2O3. The extended absorbance spectrum, the reduced recombination, and the effective transport of photogenerated holes in CdS to the electrolyte facilitate enhancement in photoelectrochemical performance. From X-ray photoelectron spectroscopy and transmission electron microscopy observation of the bare and aluminum treated CdS/1D Zr:Fe2O3 photoanodes, It could be confirmed that the 1D Zr:Fe2O3 nanorods were covered by the CdS layer and aluminum oxide layer present on surface of CdS. Furthermore, the photocurrent and stability of the CdS/Zr:Fe2O3 nanorods was significantly enhanced by Al2O3 compared to bare CdS/Zr:Fe2O3 heterojunction due to its ability to act as an effective hole transport as well as photo-corrosion protecting layer. These remarkable enhancements in light energy harvesting, improvement in charge transport and stability directly suggest the usefulness of photoanodes for solar hydrogen generation
      PubDate: 2017-03-20T03:22:43.992775-05:
      DOI: 10.1002/cssc.201700140
       
  • Metal Doping for Enhancing the Photoelectrochemical Behavior of LaFeO3
           Photocathodes
    • Authors: María Isabel Díez-García; Roberto Gómez
      Abstract: The development of tandem devices for water photosplitting requires finding photocathodic materials based on earth-abundant elements and showing long-term stability in aqueous electrolytes. Ternary metal oxides seem to be a viable option, among which perovskites stand out. In this context, transparent and compact LaFeO3 thin film electrodes have been prepared by sol-gel, both undoped and doped with metals (M) such as magnesium or zinc. Pristine electrodes support the development of cathodic photocurrents in 0.1 M NaOH aqueous solutions, particularly in the presence of oxygen, with an onset potential as high as 1.4 V vs. RHE. Doping with Mg or Zn leads to an important enhancement of the photocurrent, which peaks for a stoichiometry LaFe0.95M0.05O3 with a six-fold enhancement with respect to the pristine material. Such an improvement is attributed to an increase in both the density and mobility of the majority carriers, although a contribution of surface passivation cannot be excluded.
      PubDate: 2017-03-20T02:10:51.269277-05:
      DOI: 10.1002/cssc.201700166
       
  • NASICON-Bi2O3 composite electrolyte for all-solid-state lithium batteries:
           low-temperature fabrication and conductivity enhancement
    • Authors: Sang-Don Lee; Kyu-Nam Jung, Hyeongil Kim, Hyun-Seop Shin, Seung-Wan Song, Min-Sik Park, Jong-Won Lee
      Abstract: All-solid-state lithium batteries offer notable advantages over conventional Li-ion batteries with liquid electrolytes in terms of energy density, stability, and safety. To realize this technology, it is critical to develop highly reliable solid-state inorganic electrolytes with high ionic conductivities and acceptable processability. Li1+xAlxTi2-x(PO4)3 (LATP) with a NASICON (Na superionic conductor)-like structure is regarded as a potential solid electrolyte, owing to its high "bulk" conductivity (~10-3 S cm-1) and excellent stability against air and moisture. However, the solid LATP electrolyte still suffers from a low "total" conductivity, mainly due to the blocking effect of grain boundaries to Li+ conduction. Here, we propose an LATP-Bi2O3 composite solid electrolyte showing a very high total conductivity (9.4 × 10-4 S cm-1) at room temperature. We suggest that Bi2O3 acts as a microstructural modifier to effectively reduce the fabrication temperature of the electrolyte while enhancing its ionic conductivity. Bi2O3 promotes the densification of the LATP electrolyte, thereby improving its structural integrity, and at the same time, it facilitates Li+ conduction, leading to reduced grain boundary resistance. The feasibility of the LATP-Bi2O3 composite electrolyte in all-solid-state Li batteries is also examined in this study.
      PubDate: 2017-03-20T02:10:44.184087-05:
      DOI: 10.1002/cssc.201700104
       
  • Design Principles for Covalent Organic Frameworks in Energy Storage
           Applications
    • Authors: Sampath B Alahakoon; Christina M Thompson, Gino Occhialini, Ronald Alexander Smaldone
      Abstract: Covalent organic frameworks (COFs) are an exciting class of microporous materials that have been explored as energy storage materials for more than a decade. This review will discusses the efforts to develop these materials for applications in gas and electrical power storage. This review will also discuss some of the design strategies for developing the gas sorption properties of COFs and mechanistic studies on their formation.
      PubDate: 2017-03-16T21:40:28.994571-05:
      DOI: 10.1002/cssc.201700120
       
  • One-Pot Process for Hydrodeoxygenation of Lignin to Alkanes Using Ru-Based
           Bimetallic and Bifunctional Catalysts Supported on Zeolite Y
    • Authors: Hongliang Wang; Hao Ruan, Maoqi Feng, Yuling Qin, Heather Job, Langli Luo, Chongmin Wang, Mark H. Engelhard, Erik Kuhn, Xiaowen Chen, Melvin P. Tucker, Bin Yang
      Abstract: The synthesis of high-efficiency and low-cost catalysts for hydrodeoxygenation (HDO) of waste lignin to advanced biofuels is crucial for enhancing current biorefinery processes. Inexpensive transition metals, including Fe, Ni, Cu, and Zn, were severally co-loaded with Ru on HY zeolite to form bimetallic and bifunctional catalysts. These catalysts were subsequently tested for HDO conversion of softwood lignin and several lignin model compounds. Results indicated that the inexpensive earth-abundant metals could modulate the hydrogenolysis activity of Ru and decrease the yield of low-molecular-weight gaseous products. Among these catalysts, Ru-Cu/HY showed the best HDO performance, affording the highest selectivity to hydrocarbon products. The improved catalytic performance of Ru-Cu/HY was probably a result of the following three factors: (1) high total and strong acid sites, (2) good dispersion of metal species and limited segregation, and (3) high adsorption capacity for polar fractions, including hydroxyl groups and ether bonds. Moreover, all bifunctional catalysts proved to be superior over the combination catalysts of Ru/Al2O3 and HY zeolite.Lignin to advanced biofuels: High yields (26–32 wt %) of alkanes in jet fuel or diesel range are directly produced through aqueous-phase hydrodeoxygenation (HDO) conversion of softwood lignin catalyzed by Ru-based bimetallic catalysts supported on zeolite Y. These bimetallic and bifunctional catalysts show high efficiency compared with the combination catalysts Ru/Al2O3 and HY zeolite.
      PubDate: 2017-03-16T09:11:21.068842-05:
      DOI: 10.1002/cssc.201700160
       
  • Electrochemical Behavior of PEDOT/Lignin in Ionic Liquid Electrolytes:
           Suitable Cathode/Electrolyte System for Sodium Batteries
    • Authors: Nerea Casado; Matthias Hilder, Cristina Pozo-Gonzalo, Maria Forsyth, David Mecerreyes
      Abstract: Biomass-derived polymers, such as lignin, contain quinone/ hydroquinone redox moieties that can be used to store charge. Composites based on the biopolymer lignin and several conjugated polymers have shown good charge-storage properties. However, their performance has been only studied in acidic aqueous media limiting their applications mainly to supercapacitors. Here, we show that PEDOT/lignin (PEDOT: poly(3,4-ethylenedioxythiophene)) biopolymers are electroactive in aprotic ionic liquids (ILs) and we move a step further by assembling sodium full cell batteries using PEDOT/lignin as electrode material and IL electrolytes. Thus, the electrochemical activity and cycling of PEDOT/lignin electrodes was investigated in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyrTFSI), 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (BMPyrFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI) and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMImFSI) IL electrolytes. The effects of water and sodium salt addition to the ILs were investigated to obtain optimum electrolyte systems for sodium batteries. Finally, sodium batteries based on PEDOT/lignin cathode with imidazolium-based IL electrolyte showed higher capacity values than pyrrolidinium ones, reaching 70 mAhg−1. Our results demonstrate that PEDOT/lignin composites can serve as low cost and sustainable cathode materials for sodium batteries.Sustai-Na-ble batteries: Electroacitivity of PEDOT/lignin (PEDOT: poly(3,4-ethylenedioxythiophene)) biopolymer is studied in aprotic ionic liquids, demonstrating an effective cathode/electrolyte system that is applied to develop sustainable sodium batteries. These results open up the possibility to use other lignin-derived cathodes in sodium batteries as well as PEDOT/lignin in other electrochemical devices using ionic liquids as electrolytes.
      PubDate: 2017-03-16T09:06:07.821737-05:
      DOI: 10.1002/cssc.201700012
       
  • Operando soft X-ray absorption spectroscopic study on a solid oxide fuel
           cell cathode during electrochemical oxygen reduction
    • Authors: Takashi Nakamura; Ryo Oike, Yuta Kimura, Yusuke Tamenori, Tatsuya Kawada, Koji Amezawa
      Abstract: Operando soft X-ray absorption spectroscopic technique, which could analyze electronic structures of the electrode materials at elevated temperature and controlled atmosphere under electrochemical polarization, was established and its availability was demonstrated by investigating electronic structural changes of an La2NiO4+d dense film electrode during electrochemical oxygen reduction reaction. Clear O K-edge and Ni L-edge X-ray absorption spectra could be obtained below 773 K in fully atmospheric pressure of 100 ppm O2-He, 0.1% O2-He and 1% O2-He gas mixtures. By the PO2 change and the application of electrical potential, considerable spectral changes were observed in O K-edge X-ray absorption spectra while only small spectral changes were observed in Ni L-edge X-ray absorption spectra. Pre-edge peak of the O K-edge X-ray absorption spectra, which reflects the unoccupied pDOS of Ni3d-O2p hybridization, increased/deceased with cathodic/anodic polarization, respectively. The electronic structural changes of the outermost orbital of the electrode material due to electrochemical polarization were successfully confirmed by the operando X-ray absorption spectroscopy developed in this study.
      PubDate: 2017-03-16T07:40:52.498591-05:
      DOI: 10.1002/cssc.201700237
       
  • Interfacial Engineering of Perovskite Solar Cells by Employing a
           Hydrophobic Copper Phthalocyanine Derivative as Hole-Transporting Material
           with Improved Performance and Stability
    • Authors: Xiaoqing Jiang; Ze Yu, Jianbo Lai, Yuchen Zhang, Maowei Hu, Ning Lei, Dongping Wang, Xichuan Yang, Licheng Sun
      Abstract: In high-performance perovskite solar cells (PSCs), hole-transporting materials (HTMs) play an important role in extracting and transporting the photo-generated holes from the perovskite absorber to the cathode, thus reducing unwanted recombination losses and enhancing the photovoltaic performance. Herein, solution-processable tetra-4-(bis(4-tert-butylphenyl)amino)phenoxy-substituted copper phthalocyanine (CuPc-OTPAtBu) was synthesized and explored as a HTM in PSCs. The optical, electrochemical, and thermal properties were fully characterized for this organic metal complex. The photovoltaic performance of PSCs employing this CuPc derivative as a HTM was further investigated, in combination with a mixed-ion perovskite as a light absorber and a low-cost vacuum-free carbon as cathode. The optimized devices [doped with 6 % (w/w) tetrafluoro-tetracyano-quinodimethane (F4TCNQ)] showed a decent power conversion efficiency of 15.0 %, with an open-circuit voltage of 1.01 V, a short-circuit current density of 21.9 mA cm−2, and a fill factor of 0.68. Notably, the PSC devices studied also exhibited excellent long-term durability under ambient condition for 720 h, mainly owing to the introduction of the hydrophobic HTM interlayer, which prevents moisture penetration into the perovskite film. The present work emphasizes that solution-processable CuPc holds a great promise as a class of alternative HTMs that can be further explored for efficient and stable PSCs in the future.Lighten up: Solution-processable tetra-4-(bis(4-tert-butylphenyl)amino)phenoxy-substituted copper phthalocyanine (CuPc-OTPAtBu) is synthesized and explored as a hole-transporting material (HTM) in perovskite solar cells, showing a decent efficiency of 15.0 % together with excellent long-term stability.
      PubDate: 2017-03-16T05:19:13.84817-05:0
      DOI: 10.1002/cssc.201700150
       
  • An In-Depth Structural Study of the Carbon Dioxide Adsorption Process in
           the Porous Metal–Organic Frameworks CPO-27-M
    • Authors: Breogán Pato-Doldán; Mali H. Rosnes, Pascal D. C. Dietzel
      Abstract: The CO2 adsorption process in the family of porous metal–organic framework materials CPO-27-M (M=Mg, Mn, Co, Ni, Cu, and Zn) was studied by variable-temperature powder synchrotron X-ray diffraction under isobaric conditions. The Rietveld analysis of the data provided a time-lapse view of the adsorption process on CPO-27-M. The results confirm the temperature-dependent order of occupation of the three adsorption sites in the pores of the CPO-27-M materials. In CPO-27-M (M=Mg, Mn, Co, Ni, and Zn), the adsorption sites are occupied in sequential order, primarily because of the high affinity of CO2 for the open metal sites. CPO-27-Cu deviates from this stepwise mechanism, and the adsorption sites at the metal cation and the second site are occupied in parallel. The temperature dependence of the site occupancy of the individual CO2 adsorption sites derived from the diffraction data is reflected in the shape of the volumetric sorption isotherms. The fast kinetics and high reversibility observed in these experiments support the suitability of these materials for use in temperature- or pressure-swing processes for carbon capture.All about adsorption: A time-lapse view of the CO2 adsorption process in the CPO-27-M family is obtained with the help of powder synchrotron X-ray diffraction. The results provide insights into the host–guest structures of the CO2 molecules within the metal–organic frameworks on the molecular level and the temperature-dependent order of occupation of the different adsorption sites in the pores.
      PubDate: 2017-03-16T05:19:11.689676-05:
      DOI: 10.1002/cssc.201601752
       
  • Reliable Performance Characterization of Mediated Photocatalytic
           Water-Splitting Half Reactions
    • Authors: Lihao Han; Meng Lin, Sophia Haussener
      Abstract: Photocatalytic approaches using two sets of semiconductor particles and a pair of redox-shuttle mediators are considered as a safe and economic solution for solar water splitting. Here, accurate experimental characterization techniques for photocatalytic half reactions are reported, investigating the gas as well as the liquid products. The methods are exemplified utilizing photocatalytic titania particles in an iron-based aqueous electrolyte for effective oxygen evolution and mediator reduction reactions under illumination. Several product characterization methods, including an optical oxygen sensor, pressure sensor, gas chromatography, and UV/Vis spectroscopy are used and compared for accurate, high-resolution gas-products and mediator conversion measurements. Advantages of each technique are discussed. A high Faraday efficiency of 97.5±2 % is calculated and the reaction rate limits are investigated.A closer look: Various reliable characterization methods for a photocatalytic reactor consisting of semiconductor particles and mediator shuttles are proposed. The method is exemplified utilizing photocatalytic titania particles in an iron-based aqueous electrolyte for effective oxygen evolution and mediator reduction reactions under illumination. Several product characterization methods, including an optical oxygen sensor, pressure sensor, gas chromatography, and UV/Vis spectroscopy are used and compared.
      PubDate: 2017-03-16T05:19:08.477796-05:
      DOI: 10.1002/cssc.201601901
       
  • Solvent- and Halogen-Free Modification of Biobased Polyphenols to
           Introduce Vinyl Groups: Versatile Aromatic Building Blocks for Polymer
           Synthesis
    • Authors: Antoine Duval; Luc Avérous
      Abstract: Various biobased polyphenols (lignins and condensed tannins) were derivatized with vinyl ethylene carbonate, a functional cyclic carbonate, to obtain multifunctional aromatic polymers bearing vinyl groups. The reaction was optimized on a condensed tannin and soda lignin. In both cases, full conversion of the phenol groups was achieved in only 1 h at 150 °C without solvent and with K2CO3 as a cheap and safe catalyst. This reaction was later applied to other condensed tannins and technical lignins (Kraft and organosolv), showing only little dependence on the chemical structure of the polyphenols. The obtained derivatives were thoroughly characterized by 1H and 31P NMR spectroscopy, FTIR spectroscopy, and size-exclusion chromatography. The developed method was compared with previously published protocols for the introduction of vinyl groups on lignin, and shows promising advances toward the modification of biobased polyphenols according to green chemistry principles. The obtained macromolecules show great potential as highly versatile biobased aromatic building blocks for the synthesis of polymers through, for example, radical, metathesis, or thiol–ene reactions.Green vinyls: Vinyl groups are grafted quantitatively onto the phenolic OH groups of lignins and tannins in a solvent- and halogen-free reaction. Vinyl ethylene carbonate, a functional five-membered cyclic carbonate, is used as reagent, and K2CO3 as a cheap and safe catalyst. The obtained biobased aromatic macromolecules containing vinyl groups are versatile building blocks for polymer synthesis.
      PubDate: 2017-03-16T05:06:10.357052-05:
      DOI: 10.1002/cssc.201700066
       
  • Modified fullerenes for Efficient Electron Transport Layer-Free
           Perovskite:Fullerene Blend-Based Solar Cells
    • Authors: Juan L. Delgado; Rafael Sandoval-Torrientes, Nazario Martín, Ramón Tena-Zaera, Silvia Collavini, ivet kosta, Jorge Pascual, Inés García-Benito
      Abstract: A variety of novel chemically modified fullerenes, showing different electron accepting capabilities, has been synthesized and used to prepare electron transport layer(ETL)-free solar cells based on perovskite:fullerene blends. In particular, isoxazolino[60] fullerenes are proven to be a good candidate for processing blend films with CH3NH3PbI3 and obtaining enhanced power conversion efficiency (PCE) ETL-free perovskite solar cells, improving state-of-the-art PCE (i.e. 14.3%) for this simplified device architecture. Beneficial impact for pyrazolino and methano[60]fullerene derivatives versus pristine [60]fullerene is also shown. Furthermore, a clear correlation between the LUMO energy level of the fullerene component and the open circuit voltage of the solar cells is found. Apart from the new knowledge on innovative fullerene derivatives for perovskite solar cells, the universality and versatility of perovskite:fullerene blend films to obtain efficient ETL-free perovskite solar cells is demonstrated.
      PubDate: 2017-03-15T09:41:09.181806-05:
      DOI: 10.1002/cssc.201700180
       
  • Artificial Photosynthesis of Alcohols via Multi-functionalized
           Semiconductor Photocathodes
    • Authors: Yuqian Zhang; Bo Han, Yanjie Xu, Dongning Zhao, Yongjian Jia, Rong Nie, Zhouhe Zhu, Fengjuan Chen, Jianguo Wang, Huanwang Jing
      Abstract: Novel artificial photosynthesis systems are devised as cells of dye/Pd/NR-MOx (M = Ti, Zn) Co-Pi/W:BiVO4 that convert efficiently CO2 to alcohols. The photocathodes are amino-functionalized, palladium deposited and in-situ sensitized nano-TiO2 or ZnO/FTO electrodes that are characterized by XPS, TEM, XRD, UV-vis spectra and determined by electrochemical techniques. The cell of dye/Pd/S-TiO2 Co-Pi/W:BiVO4 uniquely generates ethanol under irradiation of 200 mW/cm2, reaching 0.56 % light quantum efficiency (QE) at 0.56 V and 0.13 % QE without external electron supply. The cell of dye/Pd/N-ZnO Co-Pi/W:BiVO4 solely produces methanol in a rate of 42.8 μM h-1 cm-2 at 0.56 V of a Si-solar cell, that is far less than the electrochemical voltage of water splitting (1.23 V). Its QE reaches to 0.38 % that is equal to plants. The isotopic labelling experiments confirm the carbon source and oxygen releasing. The selectivity for alcohols of multi-functionalized semiconductors is discussed.
      PubDate: 2017-03-15T06:40:27.154913-05:
      DOI: 10.1002/cssc.201601828
       
  • Sulfur-doped porphyrinic carbon nanostructures synthesized by amorphous
           MoS2 for oxygen reduction reaction in an acid medium
    • Authors: Hyun-Suk Park; Sang-Beom Han, Da-Hee Kwak, Gyu-Ho Lee, In-Ae Choi, Do-Hyoung Kim, Kyeng-Bae Ma, Min-Cheol Kim, Kyung-Won Park
      Abstract: To develop doped carbon nanostructures as non-precious metal cathode catalysts, we synthesize the nanocomposites using SBA-15 and 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin-Fe(III) chloride with different ratios of amorphous MoS2 precursor. From various analyses, it was found that during the pyrolysis at 900 oC under an N2 atmosphere, the amorphous MoS2 precursor was decomposed into Mo and S, facilitating the formation of graphene sheet-like carbon with MoC and doping of sulfur in the carbon. Especially, in the case of Mo/S/C-10, most of the 10 wt% MoS2 precursor was decomposed, thus forming S-doped carbon which was grown on MoC phase without crystalline MoS2 phase. Furthermore, Mo/S/C-10 exhibited enhanced ORR performance (specific activity of 1.23 mA cm-2 at 0.9 V and half-wave potential of 0.864 V), compared to a commercial Pt catalyst, due to heteroatom-doped carbon nanostructure with a fairly high specific surface area. In the polarization curve of the unit cell measured at 80 oC under an ambient pressure, Mo/S/C-10 as a cathode catalyst exhibited a maximal power density of 314 mW cm-2 and current density of 280 mA cm-2 at 0.6 V.
      PubDate: 2017-03-15T00:40:59.517102-05:
      DOI: 10.1002/cssc.201700147
       
  • Electrochemical Reduction of Oxygen in Aprotic Ionic Liquids Containing
           Metal Cations: A Case Study on the Na–O2 system
    • Authors: Eneko Azaceta; Lukas Lutz, Alexis Grimaud, Jose Manuel Vicent-Luna, Said Hamad, Luis Yate, German Cabañero, Hans-Jurgen Grande, Juan A. Anta, Jean-Marie Tarascon, Ramon Tena-Zaera
      Abstract: Metal–air batteries are intensively studied because of their high theoretical energy-storage capability. However, the fundamental science of electrodes, electrolytes, and reaction products still needs to be better understood. In this work, the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) was chosen to study the influence of a wide range of metal cations (Mn+) on the electrochemical behavior of oxygen. The relevance of the theory of Lewis hard and soft acids and bases to predict satisfactorily the reduction potential of oxygen in electrolytes containing metal cations is demonstrated. Systems with soft and intermediate Mn+ acidity are shown to facilitate oxygen reduction and metal oxide formation, whereas oxygen reduction is hampered by hard acid cations such as sodium and lithium. Furthermore, DFT calculations on the energy of formation of the resulting metal oxides rationalize the effect of Mn+ on oxygen reduction. A case study on the Na–O2 system is described in detail. Among other things, the Na+ concentration of the electrolyte is shown to control the electrochemical pathway (solution precipitation vs. surface deposition) by which the discharge product grows. All in all, fundamental insights for the design of advanced electrolytes for metal–air batteries, and Na–air batteries in particular, are provided.The softer the better: The oxygen reduction reaction (ORR) in an aprotic ionic liquid is found to be governed by the Lewis acidity of metal cations. Soft cations catalyze the ORR at less negative onset potentials, whereas hard cations hamper the ORR and result in more negative onset potentials. These findings are relevant to designing advanced electrolytes for high-performance metal–air batteries.
      PubDate: 2017-03-14T09:10:42.856909-05:
      DOI: 10.1002/cssc.201601464
       
  • Size-Dependent Activity of Palladium Nanoparticles: Efficient Conversion
           of CO2 into Formate at Low Overpotentials
    • Authors: Motiar Rahaman; Abhijit Dutta, Peter Broekmann
      Abstract: Remarkable size-dependent activity of palladium nanoparticles (PdNPs) towards formate production is evident at very low overpotentials (−0.1 to −0.5 V vs. RHE). Size-selective PdNPs, chemically synthesized at sizes of 3.8–10.7 nm, effected an electrochemical CO2 reduction reaction in aqueous 0.5 m NaHCO3. The faradaic efficiency of formate production (FEformate) on 3.8 nm PdNPs exceeded 86 % at E=−0.1 V versus RHE, whereas on 6.5 nm PdNPs an even higher FEformate of 98 % was observed. However, FEformate decreased for larger PdNPs. The superior efficiency towards formate production at low overpotentials is rationalized in terms of a changed catalytic pathway through PdH phases. The observed maximum in the formate efficiency for a mean particle size of about 6.5 nm is discussed in terms of counterbalancing the size-dependent effects of a competing CO2 reduction reaction and a parasitic hydrogen evolution reaction. Production rates of formate are also remarkably high at −0.3 V versus RHE with 539.9 and 452.3 ppm h−1 mgPd−1 for the 6.5 and 3.8 nm PdNPs, respectively.Smaller isn't better: The size-dependent activity of palladium nanoparticles (PdNPs) towards formate production has been studied at low overpotentials for NPs with sizes of 3.8–10.7 nm. A maximum of 98 % in the formate efficiency was observed for the 6.5 nm PdNPs. The size dependency of the formate efficiency is related to the counterbalancing effects of a competing CO2 reduction reaction and a parasitic hydrogen evolution reaction.
      PubDate: 2017-03-14T09:10:33.691991-05:
      DOI: 10.1002/cssc.201601778
       
  • MechanoAPI-ILs: Pharmaceutical Ionic Liquids Obtained through
           Mechanochemical Synthesis
    • Authors: Inês C. B. Martins; M. Conceição Oliveira, Hermínio P. Diogo, Luís C. Branco, M. Teresa Duarte
      Abstract: An alternative, efficient, and green synthetic strategy for the preparation of pharmaceutical ionic liquids using mechanochemistry (MechanoAPI-ILs) is reported. Six new API-ILs based on gabapentin and l-glutamic acid were successfully synthesized and characterized, demonstrating that mechanochemistry is a very promising synthetic strategy. Results compare both the new and the classical approach and clearly show the advantages of the new method. This new technique is faster, solvent free, reproducible, selective, and leads to higher yields.A solid state strategy: For the first time, mechanochemistry is used in the preparation of pharmaceutical ionic liquids (MechanoAPI-ILs). Six new API-ILs are successfully synthesized and characterized, demonstrating this to be a very promising synthetic strategy. The technique is faster, solvent free, reproducible, selective, and leads to higher yields compared to conventional processes
      PubDate: 2017-03-14T03:05:30.471204-05:
      DOI: 10.1002/cssc.201700153
       
  • Solid Confinement of Quantum Dots in ZIF-8 for Efficient and Stable
           Color-Conversion White LEDs
    • Authors: Wen Ying; Yiyin Mao, Xiaobing Wang, Yi Guo, Haihing He, Zhizhen Ye, Shuit-Tong Lee, Xinsheng Peng
      Abstract: The powder form and low photoluminescence quantum yield (PLQY) of fluorescent metal-organic frameworks (MOFs) present serious obstacle to fabricating high-efficiency film-like lighting devices. Here, we present a facile way to produce thin films of CdSexS1-x/ZnS quantum dots (QDs)@ZIF-8 with high PLQY by encapsulating red, green, and blue CdSexS1-x/ZnS QDs in ZIF-8 through a one-pot solid confinement conversion process. The QDs@ZIF-8 thin film emits warm white light with good color quality, and presents nice thermal stability and long-term duribility.
      PubDate: 2017-03-13T22:20:51.01769-05:0
      DOI: 10.1002/cssc.201700223
       
  • Direct access to primary amines and particle morphology control in
           nanoporous CO2 sorbents
    • Authors: Nesibe A Dogan; Ercan Ozdemir, Cafer T Yavuz
      Abstract: Chemical tuning of nanoporous, solid sorbents for an ideal CO2 binding requires unhindered amine functional groups on the pore walls. Although common for soluble organics, post-synthetic reduction of nitriles in porous networks often fail due to the insufficient and irreversible metal hydride penetration. Here, we synthesized a nanoporous network with pendant nitrile groups, microsphere morphology and in large scale. The hollow microspheres were easily decorated with primary amines through in situ reduction by widely available boranes. CO2 capture capacity of the modified sorbent was increased up to an eight times of the starting nanoporous network with a high heat of adsorption (98 kJ/mol). Surface area can be easily tuned between 1 and 354 m2/g. Average particle size (~50 µm) is also quite suitable for CO2 capture applications where processes like fluidized bed require spheres of micron sizes.
      PubDate: 2017-03-13T10:20:27.185637-05:
      DOI: 10.1002/cssc.201700190
       
  • Hydroxide-self-feeding high-temperature alkaline direct formate fuel cells
    • Authors: Y.S. Li; X.D. Sun, Y. Feng
      Abstract: Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction block the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenizimidazole membrane-based direct formate fuel cells (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 oC. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm-2, an order of magnitude higher than both alkaline direct ethanol fuel cell and alkaline direct methanol fuel cell, mainly because the hydrolysis of formate provides enough OH ions for formate oxidation reaction. It was also found that this hydroxide-self-feeding high-temperature alkaline DFFC shows a stable 100-minute constant-current discharge at 90 oC, proving the conceptual feasibility.
      PubDate: 2017-03-11T02:35:28.919319-05:
      DOI: 10.1002/cssc.201700228
       
  • Iron-based electrodes meet water-based preparation, fluorine- free
           electrolyte and binder: a chance for more sustainable Li-ion
           batteries'
    • Authors: Mario Valvo; Anti Liivat, Henrik Eriksson, Cheuk-Wai Tai, Kristina Edström
      Abstract: Environmentally friendly and cost-effective Li-ion cells are fabricated with abundant, non-toxic LiFePO4 cathodes and Fe oxide anodes. A water-soluble alginate binder is used for coating both electrodes to reduce the environmental footprint. Critical reactivity of LiPF6-based electrolytes toward possible H2O traces in water-processed electrodes is overcome by using a LiBOB salt. The absence of fluorine in both electrolyte and binder is a cornerstone for improved cell chemistry and is demonstrated to result in stable battery operation. A dedicated approach to better exploit conversion-type anodes is also disclosed. The issue of large voltage hysteresis upon conversion/de-conversion is circumvented by operating iron oxide in a deeply lithiated Fe/Li2O form. Li-ion cells with energy efficiencies up to 92% are demonstrated when LiFePO4 is cycled versus such anodes prepared via a pre-lithiation procedure. These cells show an average energy efficiency of ≈90.66% and a mean coulombic efficiency of ≈99.65% over 320 cycles at current densities of 0.1, 0.2 and 0.3 mAcm-2, retaining nearly 100% of their initial discharge capacity and providing an unmatched operation potential of ≈2.85 V for this combination of active materials. No occurrence of Li-plating has been detected in three-electrode cells at charging rates of ≈5C. Excellent rate capabilities up to ≈30C are achieved thanks to the exploitation of size effects due to small Fe nanoparticles and their reactive boundaries.
      PubDate: 2017-03-10T15:40:35.362279-05:
      DOI: 10.1002/cssc.201700070
       
  • Predictive Guide for Collective CO2 Adsorption Properties of Mg−Al
           Mixed Oxides
    • Authors: Hyuk Jae Kwon; Soonchul Kwon, Jeong Gil Seo, In Sun Jung, You-Hwan Son, Chan Hyun Lee, Ki Bong Lee, Hyun Chul Lee
      Abstract: Although solid adsorption processes offer attractive benefits, such as reduced energy demands and penalties compared with liquid absorption processes, there are still pressing needs for solid adsorbents with high adsorption capacities, thermal efficiencies, and energy-intensive regeneration in gas-treatment processes. The CO2 adsorption capacities of layered double oxides (LDOs), which are attractive solid adsorbents, have an asymmetric volcano-type correlation with their relative crystallinities. Furthermore, new collective adsorption properties (adsorption capacity, adsorptive energy and charge-transfer amount based on the adsorbent weight) are proposed based on density functional theory (DFT) calculations and measured surface areas. The correlation of these collective properties with their crystallinities is in good agreement with the experimentally measured CO2 adsorptive capacity trend, providing a predictive guide for the development of solid adsorbents for gas-adsorption processes.Magma cum laude: The CO2 adsorption capacities of layered double oxides (LDOs) have an asymmetric volcano-type correlation with their relative crystallinities. The correlation of their adsorption capacity, adsorptive energy, and charge transfer with their crystallinities is in good agreement with the experimentally measured CO2 adsorption capacity, providing a predictive guide for the development of solid adsorbents for gas-adsorption processes.
      PubDate: 2017-03-10T10:28:11.383718-05:
      DOI: 10.1002/cssc.201601581
       
  • Controlling the hydrolysis and loss of nitrogen fertilizer (urea) using a
           nanocomposite
    • Authors: Naiqin Zhong; Linglin Zhou, Pan Zhao, Yu Chi, Dongfang Wang, Pan Wang, Ning Liu, Dongqing Cai, Zhengyan Wu
      Abstract: Urea tends to be hydrolyzed by urease and then migrate to the environment, resulting in low utilization efficiency and severe environmental contamination. To solve this problem, a fertilizer synergist (FS) was developed using sodium humate transported by a nanonetwork through hydrogen bonds. FS could effectively inhibit the hydrolysis, reduce the loss amount, and enhance the UE of nitrogen. Furthermore, FS exerted significant positive effects on the expression of several nitrogen uptake-related genes, ion flux in maize roots, the growth of crops and the organic matter in soil. FS could modify the microbial community in soil and increase the number of bacteria involved in nitrogen metabolism, organic matter degradation, the iron cycle and photosynthesis. Importantly, this technology showed high biosafety and great potential in reducing non-point agricultural pollution. Therefore, this work provides a promising method to manage nitrogen and support the sustainable development of agriculture and the environment.
      PubDate: 2017-03-10T09:12:09.656205-05:
      DOI: 10.1002/cssc.201700032
       
  • Improving Cellulose Dissolution in Ionic Liquids by Tuning the Size of the
           Ions: Impact of the Length of the Alkyl Chains in Tetraalkylammonium
           Carboxylate
    • Authors: Xiangqian Meng; Julien Devemy, Vincent Verney, Arnaud Gautier, Pascale Husson, Jean-Michel Andanson
      Abstract: Twenty ionic liquids based on tetraalkylammonium cations and carboxylate anions have been synthesized, characterized, and tested for cellulose dissolution. The amount of cellulose dissolved in these ionic liquids depends strongly on the size of the ions: from 0 to 22 wt % cellulose can be dissolved at 90 °C. The best ionic liquids are less viscous and ammonium carboxylate based ionic liquids can dissolve as much as imidazolium-based ones. The viscosity of an ionic liquid can be decreased by the addition of DMSO as a cosolvent. After the addition of cosolvent, similar amounts of cellulose per ions are reached for most ionic liquids. As observed by rheology, ionic liquids with the longest alkyl chains form a gel when a high amount of cellulose is dissolved; this drastically limits their potential. Molecular simulations and IR spectroscopy have also been used with the aim of understanding how molecular interactions differ between efficient and inefficient ionic liquids.Optimum size determination: A series of ionic liquids are investigated for their ability to dissolve cellulose. The amount of cellulose dissolved in these ionic liquids depends strongly on the size of the ions. Molecular simulations and IR spectroscopy have also been used to understand how molecular interactions differ between efficient and inefficient ionic liquids.
      PubDate: 2017-03-09T08:40:36.13828-05:0
      DOI: 10.1002/cssc.201601830
       
  • Chemicals from Biomass: Combining Ring-Opening Tautomerization and
           Hydrogenation Reactions to Produce 1,5-Pentanediol from Furfural
    • Authors: Zachary J. Brentzel; Kevin J. Barnett, Kefeng Huang, Christos T. Maravelias, James A. Dumesic, George W. Huber
      Abstract: A process for the synthesis of 1,5-pentanediol (1,5-PD) with 84 % yield from furfural is developed, utilizing dehydration/hydration, ring-opening tautomerization, and hydrogenation reactions. Although this process has more reaction steps than the traditional direct hydrogenolysis of tetrahydrofurfuryl alcohol (THFA), techno-economic analyses demonstrate that this process is the economically preferred route for the synthesis of biorenewable 1,5-PD. 2-Hydroxytetrahydropyran (2-HY-THP) is the key reaction pathway intermediate that allows for a decrease in the minimum selling price of 1,5-PD. The reactivity of 2-HY-THP is 80 times greater than that of THFA over a bimetallic hydrogenolysis catalyst. This enhanced reactivity is a result of the ring-opening tautomerization to 5-hydoxyvaleraldehyde and subsequent hydrogenation to 1,5-PD.A new approach: α,ω-Diols are promising targets for the upgrading of lignocellulosic biomass. An alternative to prior direct hydrogenolysis approaches is developed. This new pathway utilizes a highly active intermediate, 2-hydroxytetrahydropyran. The reaction proceeds through ring-opening tautomerization of the hemiacetal and subsequent hydrogenation. Techno-economic analyses demonstrate that the new pathway is economically preferred over the direct hydrogenolysis approaches.
      PubDate: 2017-03-09T08:40:25.369377-05:
      DOI: 10.1002/cssc.201700178
       
  • Electrocatalytic CO2 Reduction to Formate at Low Overpotentials on
           Electrodeposited Pd Films: Stabilized Performance by Suppression of CO
           Formation
    • Authors: Fengling Zhou; Haitao Li, Maxime Fournier, Douglas R. MacFarlane
      Abstract: Palladium nanoparticles are effective for catalytic CO2 reduction. However, CO, one of the most important products in the CO2 reduction sequence, has strong affinity for the Pd surface and poisons the catalytic sites rapidly. In this research, an electrodeposited Pd film exhibits high activity for CO2 reduction to formate with the suppression of CO formation at low overpotentials. The substrates, electrodeposition process and the post-treatment of the Pd films affect the CO2 reduction pathway significantly. The cyclic voltammetry deposition produces films that exhibit more porous morphologies and have higher current efficiencies for formate than those of films produced at constant potential. These films show stable CO2 reduction performance at low overpotentials and have high current efficiencies (≈50–60 % depending on the substrate) for formate formation at a potential of −0.4 V versus the reversible hydrogen electrode without any detectable CO formation. It seems that the Pd surface generated by the new electrodeposition process described here produces a nanostructure that can promote formate formation and suppress CO formation.Fab formate formation! Stable electrochemical reduction of CO2 on nanostructured palladium films is achieved through the suppression of CO formation at low overpotentials, and the highest faradaic efficiency (FE) for formate is 55 % at a potential of −0.4 V versus the reversible hydrogen electrode (RHE).
      PubDate: 2017-03-09T08:35:30.310053-05:
      DOI: 10.1002/cssc.201601870
       
  • Recent Progress in Metal–Organic Frameworks and Their Derived
           Nanostructures for Energy and Environmental Applications
    • Authors: Zhiqiang Xie; Wangwang Xu, Xiaodan Cui, Ying Wang
      Abstract: Metal–organic frameworks (MOFs), as a very promising category of porous materials, have attracted increasing interest from research communities due to their extremely high surface areas, diverse nanostructures, and unique properties. In recent years, there is a growing body of evidence to indicate that MOFs can function as ideal templates to prepare various nanostructured materials for energy and environmental cleaning applications. Recent progress in the design and synthesis of MOFs and MOF-derived nanomaterials for particular applications in lithium-ion batteries, sodium-ion batteries, supercapacitors, dye-sensitized solar cells, and heavy-metal-ion detection and removal is reviewed herein. In addition, the remaining major challenges in the above fields are discussed and some perspectives for future research efforts in the development of MOFs are also provided.Cleaning up with MOFs: Recent progress in the design and synthesis of metal–organic frameworks (MOFs) and MOF-derived nanomaterials for applications in lithium-ion batteries, sodium-ion batteries, supercapacitors, dye-sensitized solar cells, and heavy-metal-ion detection and removal is reviewed. Remaining major challenges in these fields are discussed and some perspectives for future research efforts in the development of MOFs are also provided.
      PubDate: 2017-03-09T06:05:48.710724-05:
      DOI: 10.1002/cssc.201601855
       
  • Interconnected Network of Core–Shell CoP@CoBiPi for Efficient Water
           Oxidation Electrocatalysis under Near Neutral Conditions
    • Authors: Liang Cui; Fengli Qu, Jingquan Liu, Gu Du, Abdullah M. Asiri, Xuping Sun
      Abstract: Developing earth-abundant electrocatalysts for efficient and stable water oxidation under near neutral conditions is of great importance but still remains a key challenge. Herein, we demonstrate the development of an interconnected network of core–shell CoP@CoBiPi through anodic polarization of a CoP nanoarray in potassium borate aqueous electrolyte (KBi). This 3 D CoP@CoBiPi exhibits high catalytic activity for water oxidation at pH 9.2 and needs an overpotential (η) of only 410 mV to drive a geometrical catalytic current density of 10 mA cm−2, with a high turnover frequency of 819 h−1 at an overpotential of 610 mV. Remarkably, this catalyst also demonstrates high long-term electrochemical stability with its activity being maintained for at least 27 h in KBi. This study provides us an attractive earth-abundant 3 D catalyst electrode for water-splitting devices toward efficient and stable water oxidation under benign conditions.CoP–shell catalyst: Interconnected 3 D network of core–shell CoP@CoBiPi is directly transformed from a CoP nanowire array on Ti mesh through an anodic-polarization method in borate electrolyte. The resulting material behaves as a high active and robust oxygen evolution catalyst under near neutral conditions, capable of driving 10 mA cm−2 at an overpotential of 410 mV in 0.1 m KBi at room temperature.
      PubDate: 2017-03-09T06:00:51.235782-05:
      DOI: 10.1002/cssc.201700113
       
  • Towards Versatile and Sustainable Hydrogen Production through
           Electrocatalytic Water Splitting: Electrolyte Engineering
    • Authors: Tatsuya Shinagawa; Kazuhiro Takanabe
      Abstract: Recent advances in power generation from renewable resources necessitate conversion of electricity to chemicals and fuels in an efficient manner. Electrocatalytic water splitting is one of the most powerful and widespread technologies. The development of highly efficient, inexpensive, flexible, and versatile water electrolysis devices is desired. This review discusses the significance and impact of the electrolyte on electrocatalytic performance. Depending on the circumstances under which the water splitting reaction is conducted, the required solution conditions, such as the identity and molarity of ions, may significantly differ. Quantitative understanding of such electrolyte properties on electrolysis performance is effective to facilitate the development of efficient electrocatalytic systems. The electrolyte can directly participate in reaction schemes (kinetics), affect electrode stability, and/or indirectly impact the performance by influencing the concentration overpotential (mass transport). This review aims to guide fine-tuning of the electrolyte properties, or electrolyte engineering, for (photo)electrochemical water splitting reactions.It's what water splitting craves: Efficient, inexpensive, flexible, and versatile devices for electrocatalytic water splitting are highly desired. This review discusses the significance and impact of the electrolyte on electrocatalytic performance, with a particular focus placed on the role of ions in the kinetics and mass transport.
      PubDate: 2017-03-09T05:55:33.959178-05:
      DOI: 10.1002/cssc.201601583
       
  • High Areal Capacity Si-LiCoO₂ Batteries from Electrospun Composite
           Fiber Mats
    • Authors: Ethan Self; Michael Naguib, Rose Ruther, Emily McRen, Ryszard Wycisk, Gao Liu, Jagjit Nanda, Peter Nicholas Pintauro
      Abstract: Freestanding nanofiber mat Li-ion battery anodes containing Si nanoparticles, carbon black, and poly(acrylic acid) (Si/C/PAA) are prepared using electrospinning. The mats are compacted to a high fiber volume fraction (~0.85), and interfiber contacts are welded by exposing the mat to methanol vapor. A compacted/welded fiber mat anode containing 40 wt% Si exhibits high capacities of 1,484 mAh g-1 (3,500 mAh gSi-1) at 0.1C and 489 mAh g-1 at 1C and good cycling stability (e.g., 73% capacity retention over 50 cycles). Post-mortem analysis of the fiber mats shows that the overall electrode structure is preserved during cycling. Whereas many nanostructured Si anodes are hindered by their low active material loadings and densities, thick, densely packed Si/C/PAA fiber mat anodes reported here have high areal and volumetric capacities (e.g., 4.5 mAh cm-2 and 750 mAh cm-3, respectively). A full cell containing an electrospun Si/C/PAA anode and electrospun LiCoO₂-based cathode has a high specific energy density of 270 Wh kg-1. The excellent performance of the electrospun Si/C/PAA fiber mat anodes is attributed to the: (i) PAA binder which interacts with the SiOx surface of Si nanoparticles and (ii) high material loading, high fiber volume fraction, and welded interfiber contacts of the electrospun mats.
      PubDate: 2017-03-09T02:36:08.148946-05:
      DOI: 10.1002/cssc.201700096
       
  • Acidic zeolite L as a highly efficient catalyst for dehydration of
           fructose to 5-hydroxymethylfurfural in ionic liquid
    • Authors: Zhongsen Ma; Hualei Hu, Zhongqiang Sun, Wenting Fang, Jian Zhang, Longfei Yang, Yajie Zhang, Lei Wang
      Abstract: Zeolite L was synthesized by the hydrothermal method and post-treated by NH4-exchange to adjust its acidity. The samples were systematic characterized by various techniques including XRD, XRF, N2 adsorption-desorption, SEM, Py-IR, and NH3-TPD. The results demonstrate that the NH4-exchange post-treatment increase the surface areas, micropore volume, and acidity of zeolite L. The catalytic performances of the samples were tested in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in ionic liquid (1-butyl-3-methylimidazolium bromide ([bmim]Br)). 99.1% yield of HMF was achieved when using the KL-80°C-1h sample (KL zeolite treated with 1M NH4NO3 solution at 80°C for 1h). The high efficiency could be attributed to the appropriate acid property. The catalyst could be reused for four recycles without obvious decrease in the activity.
      PubDate: 2017-03-08T06:18:19.528398-05:
      DOI: 10.1002/cssc.201700239
       
  • Nitrogen fixation by gliding arc plasma: better insight by chemical
           kinetics modelling
    • Authors: WEIZONG WANG; Bhaskar S. Patil, Stjin Heijkers, Volker Hessel, Annemie Bogaerts
      Abstract: The conversion of atmospheric nitrogen into valuable compounds, i.e., so-called nitrogen fixation, is gaining increasing interest, owing to the essential role in the nitrogen cycle of the biosphere. Plasma technology, and more specifically a gliding arc plasma, has great potential in this area, but little is known about the underlying mechanisms. Therefore, we developed a detailed chemical kinetics model for a pulsed power gliding arc reactor operating at atmospheric pressure for nitrogen oxide synthesis. Experiments are carried out to validate the model and reasonable agreement is reached between the calculated and measured NO and NO2 yields and the corresponding energy efficiency for NOx formation for different N2/O2 ratios, indicating that the model can provide a realistic picture of the plasma chemistry. Therefore, we can use the model to investigate the reaction pathways for the formation and loss of NOx. The results indicate that vibrational excitation of N2 in the gliding arc contributes significantly to activating the N2 molecules, and leads to an energy efficient way of NOx production, compared to the thermal process. Based on the underlying chemistry, the model allows us to propose solutions on how to further improve the NOx formation by gliding arc technology. Our study helps to come up with more realistic scenarios of entering a cutting-edge innovation for the decentralized production of fertilizers for agriculture via low temperature plasma.
      PubDate: 2017-03-08T06:18:17.357298-05:
      DOI: 10.1002/cssc.201700095
       
  • Extraction of Salinity-Gradient Energy by a Hybrid Capacitive-Mixing
           System
    • Authors: Jiho Lee; Hongsik Yoon, Jaehan Lee, Taeyoung Kim, Jeyong Yoon
      Abstract: Salinity-gradient energy (SGE) is a renewable energy source available wherever two solutions with different salinity mix. Capacitive-mixing (Capmix) is a technology that directly extracts the SG potential through the movements of ions in high- and low-concentration solutions. However, the energy-harvesting performance of Capmix needs further improvement. Herein, a hybrid Capmix that consists of a battery and capacitive electrodes is proposed. In this system, sodium ions and anions are captured/released by the metal oxide and carbon electrodes, respectively. The hybrid Capmix extracted an energy density that was approximately three times higher (130 J m−2) and exhibited a notable power output (97 mW m−2) compared to the previous Capmix using ion-exchange membranes. Furthermore, the hybrid system operated successfully with real river water and seawater. These results suggest that the hybrid Capmix could be a viable option to harvest energy from salinity gradients.Synergistic effect! A hybrid capacitive-mixing system that consists of a battery and capacitive electrodes with an anion-exchange membrane was fabricated to harvest salinity-gradient energy. From the developed voltage rise induced by the concentration difference of sea water and river water, the hybrid system could capture energy of up to 130 J m−2 with significant power output.
      PubDate: 2017-03-08T04:35:29.626709-05:
      DOI: 10.1002/cssc.201601656
       
  • Continuous-Flow O-Alkylation of Biobased Derivatives with Dialkyl
           Carbonates in the Presence of Magnesium–Aluminium Hydrotalcites as
           Catalyst Precursors
    • Authors: Lisa Cattelan; Alvise Perosa, Piero Riello, Thomas Maschmeyer, Maurizio Selva
      Abstract: The base-catalysed reactions of OH-bearing biobased derivatives (BBDs) including glycerol formal, solketal, glycerol carbonate, furfuryl alcohol and tetrahydrofurfuryl alcohol with non-toxic dialkyl carbonates (dimethyl and diethyl carbonate) were explored under continuous-flow (CF) conditions in the presence of three Na-exchanged Y- and X-faujasites (FAUs) and four Mg–Al hydrotalcites (HTs). Compared to previous etherification protocols mediated by dialkyl carbonates, the reported procedure offers substantial improvements not only in terms of (chemo)selectivity but also for the recyclability of the catalysts, workup, ease of product purification and, importantly, process intensification. Characterisation studies proved that both HT30 and KW2000 hydrotalcites acted as catalyst precursors: during the thermal activation pre-treatments, the typical lamellar structure of the hydrotalcite was broken down gradually into a MgO-like phase (periclase) or rather a magnesia–alumina solid solution, which was the genuine catalytic phase.Go with the flow: A sustainable route to upgrade biobased derivatives through selective, continuous-flow, and catalytic O-alkylation reactions is developed. Dialkyl carbonates are used as green alkylating reagents in the presence of hydrotalcites as precursors of a catalytic phase comprising a magnesia–alumina solid solution.
      PubDate: 2017-03-07T08:35:44.053953-05:
      DOI: 10.1002/cssc.201601765
       
  • Enzyme Immobilized on Nanoporous Carbon Derived from Metal–Organic
           Framework: A New Support for Biodiesel Synthesis
    • Authors: Li-Hao Liu; Yung-Han Shih, Wan-Ling Liu, Chia-Her Lin, Hsi-Ya Huang
      Abstract: In this study, nanoporous carbon (NPC) derived from metal–organic framework was used as support for the immobilization of Burkholderia cepacia lipase. The decorated aluminum oxide within the mesoporous NPC improved the enzyme loading efficiency as well as the catalytic ability for the transesterification of soybean oil, thus making it a promising green and sustainable catalytic system for industrial application.Enzyme immobilization: A nanoporous carbon derived from metal–organic framework is used as a support for the immobilization of Burkholderia cepacia lipase, and the resulting catalytic system shows good activity for biodiesel production.
      PubDate: 2017-03-07T08:35:33.077325-05:
      DOI: 10.1002/cssc.201700142
       
  • Carbon Dioxide Capture Adsorbents: Chemistry and Methods
    • Authors: Hasmukh A. Patel; Jeehye Byun, Cafer T. Yavuz
      Abstract: Excess carbon dioxide (CO2) emissions and their inevitable consequences continue to stimulate hard debate and awareness in both academic and public spaces, despite the widespread lack of understanding on what really is needed to capture and store the unwanted CO2. Of the entire carbon capture and storage (CCS) operation, capture is the most costly process, consisting of nearly 70 % of the price tag. In this tutorial review, CO2 capture science and technology based on adsorbents are described and evaluated in the context of chemistry and methods, after briefly introducing the current status of CO2 emissions. An effective sorbent design is suggested, whereby six checkpoints are expected to be met: cost, capacity, selectivity, stability, recyclability, and fast kinetics.Cutting the cost of carbon capture: Of the entire carbon capture and storage (CCS) operation, CO2 capture is the most costly process, constituting nearly 70 % of the price. In this tutorial review, CO2 capture technology based on adsorbents is described and evaluated in the context of chemistry and methods, after briefly introducing the current status of CO2 emissions.
      PubDate: 2017-03-07T08:30:42.04735-05:0
      DOI: 10.1002/cssc.201601545
       
  • Chemocatalytic Conversion of Cellulosic Biomass to Methyl Glycolate,
           Ethylene Glycol and Ethanol
    • Authors: Gang Xu; Aiqin Wang, Jifeng Pang, Xiaochen Zhao, Jinming Xu, Nian Lei, Jia Wang, Mingyuan Zheng, Jianzhong Yin, Tao Zhang
      Abstract: Production of chemicals and fuels from renewable cellulosic biomass is important to construction of a sustainable society, and it critically relies on the development of new and efficient transformation route starting from cellulose. Here we report a chemocatalytic conversion route from cellulosic biomass to methyl glycolate (MG), ethylene glycol (EG) and ethanol (EtOH). Under the catalysis of tungsten-based catalyst, cellulose is converted into MG with a yield as high as 57.7 C% in one-pot reaction in methanol at 240 oC and 1 MPa oxygen, and the obtained MG can be easily separated by distillation and then nearly quantitatively converted to EG at 200 oC and to EtOH at 280 oC with a selectivity of 50% through hydrogenation over Cu/SiO2 catalyst. By this approach, fine chemical MG, bulk chemical EG, and fuel additive EtOH can all be efficiently produced from renewable cellulosic materials, thus providing a new avenue to mitigating the dependence on fossil resources.
      PubDate: 2017-03-07T08:20:31.588621-05:
      DOI: 10.1002/cssc.201601714
       
  • An Experimental and Theoretical Study on the Unexpected Catalytic Activity
           of Triethanolamine for the Carboxylative Cyclization of Propargylic Amines
           with CO2
    • Authors: Yuling Zhao; Jikuan Qiu, Zhiyong Li, Huiyong Wang, Maohong Fan, Jian Ji Wang
      Abstract: The chemical conversion of CO2 under atmospheric pressure and metal-free conditions remains a great challenge. In this work, a series of alkylolamines, low-cost and biodegradable bases, were used to catalyze the carboxylative cyclization of propargyl amines with CO2. It was found that among these alkylolamines, triethanolamine (TEOA) was shown to be a highly efficient organocatalyst for this important transformation at atmospheric pressure, and a series of desired products were synthesized in good to excellent yields. After the reactions, TEOA could be easily recoveried and reused without obvious reduction in the efficiency. Density functional theory studies reveal that TEOA may activate CO2 to form a ring-shaped carbonate intermediate which plays an important role in the catalysis of the reaction. This finding provides an effective and environmentally friendly alternative route for the production of 2-oxazolidinones.
      PubDate: 2017-03-07T00:20:54.819924-05:
      DOI: 10.1002/cssc.201700241
       
  • Flexible Asymmetric Threadlike Supercapacitors Based on NiCo2Se4 Nanosheet
           and NiCo2O4/Polypyrrole Electrodes
    • Authors: Qiufan Wang; Yun Ma, Yunlong Wu, Daohong Zhang, Menghe Miao
      Abstract: Flexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all-solid-state threadlike supercapacitor with a NiCo2Se4 positive electrode and a NiCo2O4@PPy (PPy: polypyrrole) negative electrode. The as-prepared electrodes display outstanding volume specific capacitance (14.2 F cm−3) and excellent cycling performance (94 % retention after 5000 cycles at 0.6 mA) owing to their nanosheet and nanosphere structures. The asymmetric all-solid-state threadlike supercapacitor expanded the stability voltage window from 0–1.0 V to 0–1.7 V and exhibits high volume energy density (5.18 mWh cm−3) and superior flexibility under different bending conditions. This study provides a scalable method for fabricating high performance flexible supercapacitors from easily available materials for use in wearable and portable electronics.Window of opportunity: Flexible asymmetric all-solid-state threadlike supercapacitors based on NiCo2Se4 (positive electrode) and NiCo2O4 supported on polypyrrole (negative electrode) are reported to expand the voltage window of stability and display high specific capacitance and excellent cycling performance.
      PubDate: 2017-03-06T05:30:35.370784-05:
      DOI: 10.1002/cssc.201700149
       
  • Harvesting Hydrogen Gas from Air Pollutants with an Unbiased Gas Phase
           Photoelectrochemical Cell
    • Authors: Sammy W. Verbruggen; Myrthe Van Hal, Tom Bosserez, Jan Rongé, Birger Hauchecorne, Johan A. Martens, Silvia Lenaerts
      Abstract: The concept of an all-gas-phase photoelectrochemical (PEC) cell producing hydrogen gas from volatile organic contaminated gas and light is presented. Without applying any external bias, organic contaminants are degraded and hydrogen gas is produced in separate electrode compartments. The system works most efficiently with organic pollutants in inert carrier gas. In the presence of oxygen, the cell performs less efficiently but still significant photocurrents are generated, showing the cell can be run on organic contaminated air. The purpose of this study is to demonstrate new application opportunities of PEC technology and to encourage further advancement toward PEC remediation of air pollution with the attractive feature of simultaneous energy recovery and pollution abatement.Help not wanted: An all-gas-phase unbiased photoelectrochemical cell converts volatile organic pollutants in air while recovering energy as hydrogen gas. This study demonstrates the possibility of simultaneous energy recovery and air remediation through photoelectrochemical systems.
      PubDate: 2017-03-06T02:20:50.573486-05:
      DOI: 10.1002/cssc.201601806
       
  • A Simple Zinc Catalyst for Carbamate Synthesis Directly from CO2
    • Authors: Qiao Zhang; Hao-Yu Yuan, Norihisa Fukaya, Hiroyuki Yasuda, Jun-Chul Choi
      Abstract: Several zinc salts were employed as catalysts for the synthesis of carbamates directly from aromatic amines, CO2, and silicate esters. Zn(OAc)2 offered the best performance among the salts tested. The addition of an N-donor ligand such as 1,10-phenanthroline increased the yield. The best catalytic performance of Zn(OAc)2 can be explained by carboxylate-assisted proton activation. The interaction between the substrate and the catalyst can be observed by chemical shifts in 1H and 15N NMR spectra. Isocyanate was a key intermediate, which was generated from amine and CO2. Silicate ester was finally converted to siloxane, which was determined by 29Si NMR. The commercially available catalyst system could be reused. The yield of isolated carbamate could reach up to 96 % with various substrates, and the catalytic reaction was amine-selective in the presence of other functional groups.Zinc rocks: A new method for synthesizing carbamates directly from amines and CO2 was developed. A commercially available zinc compound was used as the catalyst, and the addition of an N-donor ligand increased the yield to 96 % (isolated product). Both aliphatic and aromatic amines could be activated, and thus the utility of this reaction in organic synthesis and the polyurethane industry is broad.
      PubDate: 2017-03-03T06:00:37.231996-05:
      DOI: 10.1002/cssc.201601878
       
  • Photochemical Carboxylation of Activated C(sp3)─H Bonds with CO2
    • Authors: Yong-Yuan Gui; Wen-Jun Zhou, Jian-Heng Ye, Da-Gang Yu
      Abstract: Recent great breakthroughs in photochemical carboxylation of the challenging un-acidic C(sp3)─H bonds, including benzylic, allylic and amine C─H bonds, are highlighted here.
      PubDate: 2017-03-02T21:51:20.598119-05:
      DOI: 10.1002/cssc.201700205
       
  • Production and application of lignosulfonates and sulfonated lignin
    • Authors: Thomas Aro; Pedram Fatehi
      Abstract: Lignin is the largest reservoir of aromatic compounds on earth and has great potential to be used in many industrial applications. In this review paper, alternative methods to produce lignosulfonates from spent sulfite pulping liquors and kraft lignin from black liquor of kraft pulping process are critically reviewed. Furthermore, options to increase the sulfonate contents of lignin based products are outlined and the industrial attractiveness of them is evaluated. This evaluation will include sulfonation and sulfomethylation of lignin. To increase the sulfomethylation efficiency of lignin, various scenarios including hydrolysis, oxidation, and hydroxymethylation were compared. In the present work, the application of sulfonated lignin based products is assessed and the impact of the properties of sulfonated lignin based products on the characteristics of their end-use application is critically evaluated. It was determined that sulfonated lignin based products have been used as dispersants in cement admixtures and dye solutions more than other applications, and their molecular weight and sulfonation degree were crucial in determining their efficiency. The use of lignin based sulfonated products in composites may benefit the hydrophilicity increase of some composites, but the sulfonated products may need to be desulfonated via alkaline and/or oxygen prior to their use in composites. To be used as a flocculant, sulfonated lignin based products may need to be crosslinked to increase their molecular weight. In this work, the challenges associated with the use of lignin based products in these applications are comprehensively discussed.
      PubDate: 2017-03-02T12:50:26.798564-05:
      DOI: 10.1002/cssc.201700082
       
  • Dual Heteroatom-Doped Carbon Nanofoam-Wrapped Iron Monosulfide
           Nanoparticles: An Efficient Cathode Catalyst for Li–O2 Batteries
    • Authors: Prakash Ramakrishnan; Sangaraju Shanmugam, Jae Hyun Kim
      Abstract: Cost-effective dual heteroatom-doped 3D carbon nanofoam-wrapped FeS nanoparticles (NPs), FeS-C, act as efficient bifunctional catalysts for Li–O2 batteries. This cathode exhibits a maximum deep discharge capacity of 14 777.5 mA h g−1 with a 98.1 % columbic efficiency at 0.1 mA cm−2. The controlled capacity (500 mA h g−1) test of this cathode delivers a minimum polarization gap of 0.73 V at 0.1 mA cm−2 and is sustained for 100 cycles with an energy efficiency of approximately 64 % (1st cycle) and 52 % (100th cycle) at 0.3 mA cm−2, under the potential window of 2.0–4.5 V. X-ray photoelectron spectroscopy reveals the substantial reversible formation and complete decomposition of Li2O2. The excellent recharging ability, high rate performance, and cycle stability of this catalyst is attributed to the synergistic effect of FeS catalytic behavior and textural properties of heteroatom-doped carbon nanostructures.Bifunctional catalysts: The developed heteroatom-doped 3D carbon nanofoam-wrapped FeS nanoparticles possesses excellent bifunctional activity, recharging ability, rate performance, and long-time cycle stability for Li–O2 battery applications.
      PubDate: 2017-03-02T10:30:42.920362-05:
      DOI: 10.1002/cssc.201601810
       
  • Heterostructured WS2-MoS2 Ultrathin Nanosheets Integrated on CdS Nanorods
           to Promote Charge Separation and Migration and Improve Solar-Driven
           Photocatalytic Hydrogen Evolution
    • Authors: D. Amaranatha Reddy; Hanbit Park, Rory Ma, D. Praveen Kumar, Manho Lim, Tae Kyu Kim
      Abstract: Solar-driven photocatalytic hydrogen evolution is important to bring solar-energy-to-fuel energy-conversion processes to reality. However, there is a lack of highly efficient, stable, and non-precious photocatalysts, and catalysts not designed completely with expensive noble metals have remained elusive, which hampers their large-scale industrial application. Herein, for the first time, a highly efficient and stable noble-metal-free CdS/WS2-MoS2 nanocomposite was designed through a facile hydrothermal approach. When assessed as a photocatalyst for water splitting, the CdS/WS2-MoS2 nanostructures exhibited remarkable photocatalytic hydrogen-evolution performance and impressive durability. An excellent hydrogen evolution rate of 209.79 mmol g−1 h−1 was achieved under simulated sunlight irradiation, which is higher than the values for CdS/MoS2 (123.31 mmol g−1 h−1) and CdS/WS2 nanostructures (169.82 mmol g−1 h−1) and the expensive CdS/Pt benchmark catalyst (34.98 mmol g−1 h−1). The apparent quantum yield reached 51.4 % at λ=425 nm in 5 h. Furthermore, the obtained hydrogen evolution rate was better than those of several noble-metal-free catalysts reported previously. The observed high rate of hydrogen evolution and remarkable stability may be a result of the ultrafast separation of photogenerated charge carriers and transport between the CdS nanorods and the WS2-MoS2 nanosheets, which thus increases the number of electrons involved in hydrogen production. The proposed designed strategy is believed to potentially open a door to the design of advanced noble-metal-free photocatalytic materials for efficient solar-driven hydrogen production.Let the sun in: A new design strategy for a CdS/WS2-MoS2 nanocomposite with potential applications as sunlight-driven photocatalysts for hydrogen production is demonstrated. The observed high rate of hydrogen evolution and remarkable stability may be a result of the ultrafast separation of photogenerated charge carriers and transport between the CdS nanorods and the WS2-MoS2 nanosheets
      PubDate: 2017-03-02T10:30:38.441113-05:
      DOI: 10.1002/cssc.201601799
       
  • PdAuCu Nanobranch as Self-Repairing Electrocatalyst for Oxygen Reduction
           Reaction
    • Authors: Hongyu Gong; Xuecheng Cao, Fan Li, Yue Gong, Lin Gu, Rafael Gregorio Mendes, Mark H. Rummeli, Peter Strasser, Ruizhi Yang
      Abstract: During start-up and shut-down operations of fuel cells, high potential is inevitably experienced at cathode, which leads to the deterioration of the oxygen reduction electrocatalyst. The design of catalysts that can repair themselves under severe conditions has been identified as a primary challenge for fuel cells. Herein, self-supported PdAuCu branched nanostructure is synthesized by a hydrothermal method. By smartly utilizing the high-potential treatment, the activity of PdAuCu is significantly enhanced owing to the synergistic effect between the Pd and CuII generated by such treatment. Moreover, the high activity of PdAuCu can be well maintained by repeating the high-potential treatment. We hence propose this catalyst as a “self-repairing” catalyst in a broad sense.Self-repairing: PdAuCu nanobranched heterostructure, operating at high potentials that are inevitably experienced during start-up and shut-down operations in fuel cells, works as “self-repairing” electrocatalyst toward the oxygen reduction reaction (ORR).
      PubDate: 2017-03-02T06:00:51.686957-05:
      DOI: 10.1002/cssc.201700008
       
  • Screening the Effect of Water Vapour on Gas Adsorption Performance:
           Application to CO2 Capture from Flue Gas in Metal–Organic Frameworks
    • Authors: Nicolas Chanut; Sandrine Bourrelly, Bogdan Kuchta, Christian Serre, Jong-San Chang, Paul A. Wright, Philip L. Llewellyn
      Abstract: A simple laboratory-scale protocol that enables the evaluation of the effect of adsorbed water on CO2 uptake is proposed. 45 metal–organic frameworks (MOFs) were compared against reference zeolites and active carbons. It is possible to classify materials with different trends in CO2 uptake with varying amounts of pre-adsorbed water, including cases in which an increase in CO2 uptake is observed for samples with a given amount of pre-adsorbed water. Comparing loss in CO2 uptake between “wet” and “dry” samples with the Henry constant calculated from the water adsorption isotherm results in a semi-logarithmic trend for the majority of samples allowing predictions to be made. Outliers from this trend may be of particular interest and an explanation for the behaviour for each of the outliers is proposed. This thus leads to propositions for designing or choosing MOFs for CO2 capture in applications where humidity is present.Capturing MOFs: A simple screening strategy is proposed to follow the CO2 adsorption behaviour of 45 metal– organic frameworks (MOFs) that are pre-equilibrated with varying amounts of H2O. Different behaviours are observed and discussed, ranging from large decreases in CO2 uptake with degree of wetting to a negligible influence of water. Materials showing promising CO2 uptake are highlighted as of interest for further studies.
      PubDate: 2017-03-02T05:55:39.468406-05:
      DOI: 10.1002/cssc.201601816
       
  • Selective Hydrodeoxygenation of 5-Hydroxymethylfurfural to
           2,5-Dimethylfuran over Heterogeneous Iron Catalysts
    • Authors: Jiang Li; Jun-ling Liu, He-yang Liu, Guang-yue Xu, Jun-jie Zhang, Jia-xing Liu, Guang-lin Zhou, Qin Li, Zhi-hao Xu, Yao Fu
      Abstract: This work provided the first example of selective hydrodeoxygenation of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) over heterogeneous Fe catalysts. A catalyst prepared by the pyrolysis of an Fe-phenanthroline complex on activated carbon at 800 °C was demonstrated to be the most active heterogeneous Fe catalyst. Under the optimal reaction conditions, complete conversion of HMF was achieved with 86.2 % selectivity to DMF. The reaction pathway was investigated thoroughly, and the hydrogenation of the C=O bond in HMF was demonstrated to be the rate-determining step during the hydrodeoxygenation, which could be accelerated greatly by using alcohol solvents as additional H-donors. The excellent stability of the Fe catalyst, which was probably a result of the well-preserved active species and the pore structure of the Fe catalyst in the presence of H2, was demonstrated in batch and continuous flow fixed-bed reactors.Selective and stable Fe: Selective catalytic hydrodeoxygenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran over heterogeneous Fe catalysts is demonstrated in batch and continuous flow fixed-bed reactors. The Fe catalyst exhibited excellent stability, which is probably a result of the well-preserved active species and the pore structure of the Fe catalyst in the presence of H2.
      PubDate: 2017-03-02T05:55:34.390277-05:
      DOI: 10.1002/cssc.201700105
       
  • Supported Molybdenum Catalysts for the Deoxydehydration of
           1,4-Anhydroerythritol into 2,5-Dihydrofuran
    • Authors: Lennart Sandbrink; Klaus Beckerle, Isabell Meiners, Rebecca Liffmann, Khosrow Rahimi, Jun Okuda, Regina Palkovits
      Abstract: Efficient deoxygenation strategies are crucial for the valorization of renewable feedstocks. Deoxydehydration (DODH) enables the direct transformation of two adjacent hydroxyl groups into a double bond. Supported molybdenum-based catalysts were utilized for the first time in DODH. MoOx/TiO2 showed superior catalytic activity compared to common molybdenum salts. The catalyst efficiently converted 1,4-anhydroerythritol into 2,5-dihydrofuran in the presence of 3-octanol as reducing agent, showing high reproducibility and stability.More than the sum: Efficient deoxygenation strategies are crucial for the valorization of renewable feedstocks. Deoxydehydration (DODH) enables the direct transformation of two adjacent hydroxyl groups into a double bond. Here, the first supported molybdenum catalyst for DODH is presented. Interestingly, the TiO2-supported catalyst outperforms its molecular counterparts and shows high stability.
      PubDate: 2017-03-02T04:45:26.793629-05:
      DOI: 10.1002/cssc.201700010
       
  • Nanostructured Silica-Titania Hybrid using Fibrous Nanosilica as
           Photocatalysts
    • Authors: Nisha Bayal; Rustam Singh, Vivek Polshettiwar
      Abstract: We have developed a novel method of fabricating active TiO2 photocatalysts by tuning the morphology of catalyst support. Sustainable solution phase TiO2 deposition on silica protocol is developed over complex and expensive atomic layer deposition technique. In general, catalytic activity decreases with increase in TiO2 loading on conventional mesoporous silica because of the loss of surface area due to blocking of pores. Notably, in the case of KCC-1 as a support, because of its open fibrous morphology, even at the highest TiO2 loading, a relatively large amount of surface area remained intact. This improved the accessibility of active sites, which increased the catalytic performance of KCC-1/TiO2 photocatalyst. Fibrous nanosilica supported titania is found to be a superior photocatalyst in terms of H2 generation (26.4 mmolh-1g-1TiO2) using UV light. This study may provide a new direction for photocatalyst development by morphology control of the support.
      PubDate: 2017-03-02T03:45:30.428997-05:
      DOI: 10.1002/cssc.201700135
       
  • Simultaneous Upgrading of Furanics and Phenolics through
           Hydroxyalkylation/Aldol Condensation Reactions
    • Authors: Tuong V. Bui; Tawan Sooknoi, Daniel E. Resasco
      Abstract: The simultaneous conversion of cyclopentanone and m-cresol has been investigated on a series of solid-acid catalysts. Both compounds are representative of biomass-derived streams. Cyclopentanone can be readily obtained from sugar-derived furfurals through Piancatelli rearrangement under reducing conditions. Cresol represents a family of phenolic compounds, typically obtained from the depolymerization of lignin. In the first biomass conversion strategy proposed here, furfural is converted in high yields and selectivity to cyclopentanone (CPO) over metal catalysts such as Pd-Fe/SiO2 at 600 psi (∼4.14 MPa) H2 and 150 °C. Subsequently, CPO and cresol are further converted through acid-catalyzed hydroxyalkylation. This C−C coupling reaction may be used to generate products in the molecular weight range that is appropriate for transportation fuels. As molecules beyond this range may be undesirable for fuel production, a catalyst with a suitable porous structure may be advantageous for controlling the product distribution in the desirable range. If Amberlyst resins were used as a catalyst, C12–C24 products were obtained whereas when zeolites with smaller pore sizes were used, they selectively produced C10 products. Alternatively, CPO can undergo the acid-catalyzed self-aldol condensation to form C10 bicyclic adducts. As an illustration of the potential for practical implementation of this strategy for biofuel production, the long-chain oxygenates obtained from hydroxyalkylation/aldol condensation were successfully upgraded through hydrodeoxygenation to a mixture of linear alkanes and saturated cyclic hydrocarbons, which in practice would be direct drop-in components for transportation fuels. Aqueous acidic environments, which are typically encountered during the liquid-phase upgrading of bio-oils, would inhibit the efficiency of base-catalyzed processes. Therefore, the proposed acid-catalyzed upgrading strategy is advantageous for biomass conversion in terms of process simplicity.Would you like a fuel upgrade' We propose an attractive strategy to effectively upgrade two fractions of torrefaction simultaneously through hydroxyalkylation/aldol condensation reactions. After hydrodeoxygenation (HDO) processing, saturated alkanes with carbon chains ranging from C10–C16 are obtained, which can be used as transportation fuel or refinery feed.
      PubDate: 2017-03-01T09:45:31.373531-05:
      DOI: 10.1002/cssc.201601251
       
  • Influence of Enhanced O2 Provision on the Discharge Performance of
           Li–air Batteries by Incorporating Fluoroether
    • Authors: Hao Wan; Ya Mao, Zixuan Liu, Qingyou Bai, Zhe Peng, Jingjing Bao, Gang Wu, Yang Liu, Deyu Wang, Jingying Xie
      Abstract: As the first step during discharge, the mass transfer of oxygen should play a crucial role in Li–air batteries to tailor the growth of discharge products, however, not enough attention has been paid to this issue. Herein, we introduce an oxygen-enriching cosolvent, 1,2-(1,1,2,2-tetrafluoroethoxy) ethane (FE1), into the electrolyte, and investigate its influence on the discharge performance. The incorporation of this novel cosolvent consistently enhances the oxygen solubility of the electrolyte, and improves the oxygen diffusivity following a volcano-shape trend peaking at 50 % FE1. It is interesting that the discharge capacities obtained with the investigated electrolytes share the similar volcano trends as the oxygen transport under 50 mA gcarbon−1 and higher current densities. The improved oxygen diffusion could benefit the volumetric utilization of the air cathode, especially at the separator side, probably owing to the fast oxygen transport to moderate its concentration gradient. Our results demonstrate the importance of oxygen provision, which easily becomes the capacity-determining factor.Got Oxygen' The enhancement of oxygen provision is achieved by incorporating 1,2-(1,1,2,2-tetrafluoroethoxy) ethane as the cosolvent in the electrolyte. The oxygen's diffusivity, rather than solubility, exerts the principal effect on discharge performance of the Li–air battery, especially at higher current density, owing to the ameliorated oxygen's accessibility, which improves the utilization ratio of the whole air cathode.
      PubDate: 2017-03-01T09:45:27.807012-05:
      DOI: 10.1002/cssc.201601725
       
  • Efficient Cleavage of Lignin–Carbohydrate Complexes and Ultrafast
           Extraction of Lignin Oligomers from Wood Biomass by Microwave-Assisted
           Treatment with Deep Eutectic Solvent
    • Authors: Yongzhuang Liu; Wenshuai Chen, Qinqin Xia, Bingtuo Guo, Qingwen Wang, Shouxin Liu, Yixing Liu, Jian Li, Haipeng Yu
      Abstract: Lignocellulosic biomass is an abundant and renewable resource for the production of biobased value-added fuels, chemicals, and materials, but its effective exploitation by an energy-efficient and environmentally friendly strategy remains a challenge. Herein, a facile approach for efficiently cleaving lignin–carbohydrate complexes and ultrafast fractionation of components from wood by microwave-assisted treatment with deep eutectic solvent is reported. The solvent was composed of sustainable choline chloride and oxalic acid dihydrate, and showed a hydrogen-bond acidity of 1.31. Efficient fractionation of lignocellulose with the solvent was realized by heating at 80 °C under 800 W microwave irradiation for 3 min. The extracted lignin showed a low molecular weight of 913, a low polydispersity of 1.25, and consisted of lignin oligomers with high purity (ca. 96 %), and thus shows potential in downstream production of aromatic chemicals. The other dissolved matter mainly comprised glucose, xylose, and hydroxymethylfurfural. The undissolved material was cellulose with crystal I structure and a crystallinity of approximately 75 %, which can be used for fabricating nanocellulose. Therefore, this work promotes an ultrafast lignin-first biorefinery approach while simultaneously keeping the undissolved cellulose available for further utilization. This work is expected to contribute to improving the economics of overall biorefining of lignocellulosic biomass.Faster with microwaves: A choline chloride/oxalic acid dihydrate deep eutectic solvent (DES) is used for fractionation of wood lignocellulose (WL). A combination of DES and microwave irradiation has a synergetic effect on efficiently cleaving lignin–carbohydrate complexes and ultrafast fractionation of WL. The extracted lignin fraction is of low molecular weight, low polydispersity, and high purity.
      PubDate: 2017-03-01T07:10:36.030472-05:
      DOI: 10.1002/cssc.201601795
       
  • Synthesis Optimization, Shaping, and Heat Reallocation Evaluation of the
           Hydrophilic Metal–Organic Framework MIL-160(Al)
    • Authors: Anastasia Permyakova; Oleksandr Skrylnyk, Emilie Courbon, Maame Affram, Sujing Wang, U-Hwang Lee, Anil H. Valekar, Farid Nouar, Georges Mouchaham, Thomas Devic, Guy De Weireld, Jong-San Chang, Nathalie Steunou, Marc Frère, Christian Serre
      Abstract: The energy-storage capacities of a series of water-stable porous metal–organic frameworks, based on high-valence metal cations (Al3+, Fe3+, Cr3+, Ti4+, Zr4+) and polycarboxylate linkers, were evaluated under the typical conditions of seasonal energy-storage devices. The results showed that the microporous hydrophilic Al-dicarboxylate MIL-160(Al) exhibited one of the best performances. To assess the properties of this material for space-heating applications on a laboratory pilot scale with an open reactor, a new synthetic route involving safer, greener conditions was developed. This led to the production of MIL-160(Al) on a 400 g scale, before the material was shaped into pellets through a wet-granulation method. The material exhibited a very high energy-storage capacity for a physical-sorption material (343 Wh kg−1), which is in full agreement with the predicted value.Some like it hot: The robust hydrophilic and microporous Al dicarboxylate MIL-160(Al) is synthesized on the laboratory pilot scale, following an optimized environmentally benign synthesis route, and shaped as pellets. It is then evaluated under the conditions of a long-term heat-storage application, revealing that MIL-160(Al) outperforms the best inorganic porous solids reported so far.
      PubDate: 2017-03-01T07:10:31.712018-05:
      DOI: 10.1002/cssc.201700164
       
  • Hydrogen treated Rutile TiO2 shell in graphite core structure as a
           negative electrode for high-performance vanadium flow batteries
    • Authors: Javier Vázquez Galván; Cristina Flox, Cristian Fabregas, Edgar Ventosa, Andres Parra, Teresa Andreu, Juan Ramon Morante
      Abstract: Hydrogen treated TiO2 as electrocatalyst has been demonstrated for high performance all-vanadium redox flow batteries (VRFB) as a simple and eco-friendly strategy, boosting the obtainable battery's capacity. GF@TiO2:H electrode performs an abrupt inhibition of the hydrogen-evolution reaction (HER), which is a critical barrier for operating at high rate for long-term cycling in VRFB. Significant improvements in charge-discharge and electron transfer processes towards V3+/V2+ reaction is achieved on the surface of reduced TiO2, as a consequence of the formation of oxygen-vacancies in the lattice structure and oxygen-functional groups. Key performance indicators of VRFB have been increased in terms of high capability rates and electrolyte-utilization ratio achieved (82% at 200 mA/cm2). Additionally, high coulombic efficiency (up to 96th cycle~100%, after >97%) is obtained, demonstrating the feasibility of achieving long-term stability.
      PubDate: 2017-03-01T06:45:25.553653-05:
      DOI: 10.1002/cssc.201700017
       
  • A New CuO-Fe2O3-Mesocarbon Microbeads Conversion Anode in a
           High-Performance Lithium-Ion Battery with a Li1.35Ni0.48Fe0.1Mn1.72O4
           Spinel Cathode
    • Authors: Daniele Di Lecce; Roberta Verrelli, Daniele Campanella, Vittorio Marangon, Jusef Hassoun
      Abstract: A ternary CuO-Fe2O3-mesocarbon microbeads (MCMB) conversion anode was characterized and combined with a high-voltage Li1.35Ni0.48Fe0.1Mn1.72O4 spinel cathode in a lithium-ion battery of relevant performance in terms of cycling stability and rate capability. The CuO-Fe2O3-MCMB composite was prepared by using high-energy milling, a low-cost pathway that leads to a crystalline structure and homogeneous submicrometrical morphology as revealed by XRD and electron microscopy. The anode reversibly exchanges lithium ions through the conversion reactions of CuO and Fe2O3 and by insertion into the MCMB carbon. Electrochemical tests, including impedance spectroscopy, revealed a conductive electrode/electrolyte interface that enabled the anode to achieve a reversible capacity value higher than 500 mAh g−1 when cycled at a current of 120 mA g−1. The remarkable stability of the CuO-Fe2O3-MCMB electrode and the suitable characteristics in terms of delivered capacity and voltage-profile retention allowed its use in an efficient full lithium-ion cell with a high-voltage Li1.35Ni0.48Fe0.1Mn1.72O4 cathode. The cell had a working voltage of 3.6 V and delivered a capacity of 110 mAh gcathode−1 with a Coulombic efficiency above 99 % after 100 cycles at 148 mA gcathode−1. This relevant performances, rarely achieved by lithium-ion systems that use the conversion reaction, are the result of an excellent cell balance in terms of negative-to-positive ratio, favored by the anode composition and electrochemical features.Powerful ternary mix: A composite of CuO, Fe2O3, and mesocarbon microbeads is prepared by high-energy ball milling and applied as a conversion anode in lithium-ion batteries with a high-voltage Li1.35Ni0.48Fe0.1Mn1.72O4 spinel cathode. The cell has a working voltage of 3.6 V and delivers a capacity of 110 mAh gcathode−1 with a Coulombic efficiency above 99 % after 100 cycles at 148 mA gcathode−1.
      PubDate: 2017-03-01T06:06:24.384836-05:
      DOI: 10.1002/cssc.201601638
       
  • Towards an Understanding of Li2O2 Evolution in Li–O2 Batteries: An
           In Operando Synchrotron X-ray Diffraction Study
    • Authors: Chenjuan Liu; William R. Brant, Reza Younesi, Yanyan Dong, Kristina Edström, Torbjörn Gustafsson, Jiefang Zhu
      Abstract: One of the major challenges in developing high-performance Li–O2 batteries is to understand the Li2O2 formation and decomposition during battery cycling. In this study, this issue was investigated by synchrotron radiation powder X-ray diffraction. The evolution of Li2O2 morphology and structure was observed under actual electrochemical conditions of battery operation. By quantitatively tracking Li2O2 during discharge and charge, a two-step process was suggested for both growth and oxidation of Li2O2 owing to different mechanisms during two stages of both oxygen reduction reaction and oxygen evolution reaction. From an observation of the anisotropic broadening of Li2O2 in XRD patterns, it was inferred that disc-like Li2O2 grains are formed rapidly in the first step of discharge. These grains can stack together so that they facilitate the nucleation and growth of toroidal Li2O2 particles with a LiO2-like surface, which could cause parasitic reactions and hinder the formation of Li2O2. During the charge process, Li2O2 is firstly oxidized from the surface, followed by a delithiation process with a faster oxidation of the bulk by stripping the interlayer Li atoms to form an off-stoichiometric intermediate. This fundamental insight brings new information on the working mechanism of Li–O2 batteries.A closer look at lithium batteries: The evolution of Li2O2 is investigated by in operando synchrotron radiation powder X-ray diffraction to establish the mechanisms in the oxygen reduction reaction and the oxygen evolution reaction during the first cycle by using a 1,2-dimethoxyethane electrolyte system. By quantitatively tracking Li2O2 during cycling, a two-step process is suggested for both growth and oxidation of Li2O2.
      PubDate: 2017-03-01T02:52:29.331871-05:
      DOI: 10.1002/cssc.201601718
       
  • Carbon Dioxide Hydrogenation into Higher Hydrocarbons and Oxygenates:
           Thermodynamic and Kinetic Bounds and Progress with Heterogeneous and
           Homogeneous Catalysis
    • Authors: Gonzalo Prieto
      Abstract: Under specific scenarios, the catalytic hydrogenation of CO2 with renewable hydrogen is considered a suitable route for the chemical recycling of this environmentally harmful and chemically refractory molecule into added-value energy carriers and chemicals. The hydrogenation of CO2 into C1 products, such as methane and methanol, can be achieved with high selectivities towards the corresponding hydrogenation product. More challenging, however, is the selective production of high (C2+) hydrocarbons and oxygenates. These products are desired as energy vectors, owing to their higher volumetric energy density and compatibility with the current fuel infrastructure than C1 compounds, and as entry platform chemicals for existing value chains. The major challenge is the optimal integration of catalytic functionalities for both reductive and chain-growth steps. This Minireview summarizes the progress achieved towards the hydrogenation of CO2 to C2+ hydrocarbons and oxygenates, covering both solid and molecular catalysts and processes in the gas and liquid phases. Mechanistic aspects are discussed with emphasis on intrinsic kinetic limitations, in some cases inevitably linked to thermodynamic bounds through the concomitant reverse water–gas-shift reaction, which should be considered in the development of advanced catalysts and processes.Aiming high: The progress achieved towards the hydrogenation of CO2 to high (C2+) hydrocarbons and oxygenates, covering both solid and molecular catalysts and processes in the gas and liquid phases, is reviewed. Mechanistic aspects are discussed with emphasis on intrinsic kinetic limitations, in some cases inevitably linked to thermodynamic bounds through the concomitant reverse water–gas-shift reaction.
      PubDate: 2017-03-01T02:37:02.120564-05:
      DOI: 10.1002/cssc.201601591
       
  • Synthesis of Furandicarboxylic Acid Esters From Nonfood Feedstocks Without
           Concomitant Levulinic Acid Formation
    • Authors: Frits van der Klis; Jacco van Haveren, Daan S. van Es, Johannes H. Bitter
      Abstract: 5-Hydroxymethylfurfural (HMF) is a versatile intermediate in biomass conversion pathways. However, the notoriously unstable nature of HMF imposes challenges to design selective routes to chemicals such as furan-2,5-dicarboxylic acid (FDCA). Here, a new strategy for obtaining furans is presented, bypassing the formation of the unstable HMF. Instead of starting with glucose/fructose and thus forming HMF as an intermediate, the new route starts from uronic acids, which are abundantly present in many agro residues such as sugar beet pulp, potato pulp, and citrus peels. Conversion of uronic acids, via ketoaldonic acids, to the intermediate formylfuroic acid (FFA) esters, and subsequently to FDCA esters, proceeds without formation of levulinic acid or insoluble humins. This new route provides an attractive strategy to valorize agricultural waste streams and a route to furanic building blocks without the co-production of levulinic acid or humins.Agro-waste to polyester precursors: Furandicarboxylic acid (FDCA) is a promising biobased building block for the production of packaging materials. Current routes to FDCA involve the notoriously unstable 5-hydroxymethylfurfural as an intermediate, which leads to the formation of levulinic acid and humins. Here, a new route to 2nd generation FDCA esters starting from readily available agro-industrial residues such as sugar beet pulp and citrus pulp is presented.
      PubDate: 2017-03-01T02:36:52.074503-05:
      DOI: 10.1002/cssc.201700051
       
  • Remarkably Efficient Microvawe-Assisted Cross-Metathesis of Lipids in
           Solvent Free Conditions
    • Authors: Aman Ullah; Muhammad Arshad
      Abstract: Catalytic transformation of renewable feed stocks into fine chemicals is in high demands and olefin metathesis is one of the sophisticated tools for biomass conversion. Nevertheless, the large scale viability of such processes depends on the conversion efficiency, energy efficiency, catalytic activity, selective conversion into desired products and environmental footprint of the process. Thus, conversions of renewables using simple, swift, and efficient methods are desirable. A microwave-assisted ethenolysis and alkenolysis (using 1-5 hexadiene) of canola oil and methyl esters derived from canola oil (COME) and waste/recycled cooking oil (WOME) was carried out using ruthenium based catalytic systems. A systematic study using 1st and 2nd generation Grubbs (G1, G2) and Hoveyda-Grubbs (HG1 & HG2) catalysts was carried out. Among all ruthenium catalysts, HG2 was found to be highly active in the range of 0.002-0.1 mol% loadings. The conversions proved to be highly efficient with outstanding values of turnover numbers (TONs) and turnover frequencies (TOFs). The TONs for ethenolysis of COME (~1.5 million), direct ethenolysis of canola oil (~0.6 million), more than 1 million for WOME and above 1.6 million for cross metathesis of 1,5-hexadiene with COME were achieved. The ethenolysis of commercial methyl oleate was also performed leading to TONs ~1.2 million and TOFs 20,300 s-1 under microwave conditions.
      PubDate: 2017-02-28T21:46:01.111823-05:
      DOI: 10.1002/cssc.201601824
       
  • Morphology Engineering: A Route to Highly Reproducible and High Efficiency
           Perovskite Solar Cells
    • Authors: Dongqin Bi; Jingshan Luo, Fei Zhang, Arnaud Magrez, Evangelia Nefeli Athanasopoulou, Anders Hagfeldt, Michael Grätzel
      Abstract: Despite the rapid increase in the performance of perovskite solar cells (PSC), they still suffer from low lab-to-lab or people-to-people reproducibility. Aiming for a universal condition to high-performance devices, we investigated the morphology evolution of a composite perovskite by tuning annealing temperature and precursor concentration of the perovskite film. Here, we introduce thermal annealing as a powerful tool to generate a well-controlled excess of PbI2 in the perovskite formulation and show that this benefits the photovoltaic performance. We demonstrated the correlation between the film microstructure and electronic property and device performance. An optimized average grain size/thickness aspect ratio of the perovskite crystallite is identified, which brings about a highly reproducible power conversion efficiency (PCE) of 19.5 %, with a certified value of 19.08 %. Negligible hysteresis and outstanding morphology stability are observed with these devices. These findings lay the foundation for further boosting the PCE of PSC and can be very instructive for fabrication of high-quality perovskite films for a variety of applications, such as light-emitting diodes, field-effect transistors, and photodetectors.A matter of control: Here, we introduce thermal annealing as a powerful tool to generate a well-controlled excess of PbI2 in the perovskite formulation and show that this benefits the photovoltaic performance. An optimized average grain size/thickness aspect ratio of the perovskite crystallite is identified, which brings about a highly reproducible power conversion efficiency (PCE) of 19.5 %, with a certified value of 19.08 %.
      PubDate: 2017-02-28T07:35:55.328157-05:
      DOI: 10.1002/cssc.201601387
       
  • Direct synthesis of dimethyl carbonate from CO2 and methanol at room
           temperature using imidazolium hydrogen carbonate ionic liquid as
           recyclable catalyst and dehydrant
    • Authors: Tianxiang Zhao; Xingbang Hu, Dongsheng Wu, Rui Li, Guoqiang Yang, Youting Wu
      Abstract: Direct synthesis of dimethyl carbonate (DMC) from CO2 and CH3OH was achieved at room temperature with 74% CH3OH conversion in the presence of imidazolium hydrogen carbonate ionic liquid ([CnCmIm][HCO3]). Experimental and theoretic results reveal that [CnCmIm][HCO3] can quickly transform into a CO2-adduct. The latter serves as effective catalyst and dehydrant. Its dehydration ability is found to be reversible. The energy barrier of the rate-determining step for the DMC synthesis is only 21.7 kcal/mol. The ionic liquid can be reused easily without obvious loss on its catalytic and dehydrating ability.
      PubDate: 2017-02-28T06:50:25.861671-05:
      DOI: 10.1002/cssc.201700128
       
  • Porous Zirconium–Furandicarboxylate Microspheres for Efficient Redox
           Conversion of Biofuranics
    • Authors: Hu Li; Xiaofang Liu, Tingting Yang, Wenfeng Zhao, Shunmugavel Saravanamurugan, Song Yang
      Abstract: Biofuranic compounds, typically derived from C5 and C6 carbohydrates, have been extensively studied as promising alternatives to chemicals based on fossil resources. The present work reports the simple assembly of biobased 2,5-furandicarboxylic acid (FDCA) with different metal ions to prepare a range of metal–FDCA hybrids under hydrothermal conditions. The hybrid materials were demonstrated to have porous structure and acid–base bifunctionality. Zr-FDCA-T, in particular, showed a microspheric structure, high thermostability (ca. 400 °C), average pore diameters of approximately 4.7 nm, large density, moderate strength of Lewis-base/acid centers (ca. 1.4 mmol g−1), and a small number of Brønsted-acid sites. This material afforded almost quantitative yields of biofuranic alcohols from the corresponding aldehydes under mild conditions through catalytic transfer hydrogenation (CTH). Isotopic 1H NMR spectroscopy and kinetic studies verified that direct hydride transfer was the dominant pathway and rate-determining step of the CTH. Importantly, the Zr-FDCA-T microspheres could be recycled with no decrease in catalytic performance and little leaching of active sites. Moreover, good yields of C5 (i.e., furfural) or C4 products [i.e., maleic acid and 2(5H)-furanone] could be obtained from furfuryl alcohol without oxidation of the furan ring over these metal–FDCA hybrids. The content and ratio of Lewis-acid/base sites were demonstrated to dominantly affect the catalytic performance of these redox reactions.All from Biomass: Biobased 2,5-furandicarboxylic acid (FDCA) assembled with zirconium under solvothermal conditions can give mesoporous Zr–FDCA microspheres functionalized with enhancive Lewis-acid/base centers, which are demonstrated to be highly active and selective for catalytic transfer hydrogenation and oxidation of biofuranics to corresponding alcohols and C4 products, respectively. The robust and sustainable catalytic system shows great potential for efficient valorization of biofuranics.
      PubDate: 2017-02-28T04:21:46.754082-05:
      DOI: 10.1002/cssc.201601898
       
  • Sustainable Hypersaline Microbial Fuel Cells: Inexpensive Recyclable
           Polymer Supports for Carbon Nanotube Conductive Paint Anodes
    • Authors: Matteo Grattieri; Nelson Shivel, Iram Sifat, Massimiliano Bestetti, Shelley Minteer
      Abstract: Microbial fuel cells are an emerging technology for wastewater treatment, but in order to be commercially viable and sustainable, the electrode materials must be inexpensive, recyclable and reliable. In this paper, recyclable polymeric supports were explored for the development of anode electrodes to be applied in-field in single chamber microbial fuel cells operated in hypersaline conditions. The support was covered with a carbon-nanotube (CNT)-based conductive paint and biofilms were able to colonize the electrodes. The single chamber microbial fuel cells with Pt-free cathodes delivered a reproducible power output after 15 days of operation, achieving 12 ± 1 mW m-2 at a current density of 69 ± 7 mA m-2. The decrease of performance in long-term experiments was mostly related to inorganic precipitates on the cathode electrode and did not affect the performance of the anode, as shown by experiments replacing the cathode that regenerated the fuel cell performance. The results of these studies show the feasibility of carbon nanotube-based paint coated polymeric supports for microbial fuel cell applications.
      PubDate: 2017-02-28T03:45:26.634546-05:
      DOI: 10.1002/cssc.201700099
       
  • Systematic Molecular Design of Ketone Derivatives of Aromatic Molecules
           for Lithium-Ion Batteries: First-Principles DFT Modeling
    • Authors: Jong Hoo Park; Tianyuan Liu, Ki Chul Kim, Seung Woo Lee, Seung Soon Jang
      Abstract: The thermodynamic and electrochemical redox properties for a set of ketone derivatives of phenalenyl and anthracene have been investigated to assess their potential application for positive electrode materials in rechargeable lithium-ion batteries. Using first-principles DFT, it was found that 1) the thermodynamic stabilities of ketone derivatives are strongly dependent on the distribution of the carbonyl groups and 2) the redox potential is increased when increasing the number of the incorporated carbonyl groups. The highest values are 3.93 V versus Li/Li+ for the phenalenyl derivatives and 3.82 V versus Li/Li+ for the anthracene derivatives. It is further highlighted that the redox potential of an organic molecule is also strongly correlated with its spin state in the thermodynamically stable form.DFT modeling: Geometric configurations of a carbonyl moiety incorporated in small organic molecules such as phenalenyl and anthracene are strongly correlated with their structural stability and redox properties. This information provides an insight into establishing a design strategy for the construction of organic electrodes for lithium-ion batteries.
      PubDate: 2017-02-28T03:40:52.909042-05:
      DOI: 10.1002/cssc.201601730
       
  • Highly Active Three-Dimensional NiFe/Cu2O Nanowires/Cu Foam Electrode for
           Water Oxidation
    • Authors: Hu Chen; Yan Gao, Licheng Sun
      Abstract: Water splitting is of paramount importance for exploiting renewable energy-conversion and -storage systems, but is greatly hindered by the kinetically sluggish oxygen evolution reaction (OER). In this work, a three-dimensional, highly efficient, and durable NiFe/Cu2O nanowires/Cu foam anode (NiFe/Cu2O NWs/CF) for water oxidation in 1.0 m KOH was developed. The obtained electrode exhibited a current density of 10 mA cm−2 at a uniquely low overpotential of η=215 mV. The average specific current density (js) was estimated, on the basis of the electrocatalytically active surface area, to be 0.163 mA cm−2 at η=310 mV. The electrode also displayed a low Tafel slope of 42 mV decade−1. Moreover, the NiFe/Cu2O NWs/CF electrode could maintain a steady current density of 100 mA cm−2 for 50 h at an overpotential of η=260 mV. The outstanding electrochemical performance of the electrode for the OER was attributed to the high conductivity of the Cu foam and the specific structure of the electrode with a large interfacial area.Oxygen evolution: A three-dimensional, highly efficient, and durable NiFe/Cu2O nanowires/Cu foam anode (NiFe/Cu2O NWs/CF) is developed for the oxygen evolution reaction and exhibits extremely stable current densities of 10 mA cm−2 at a uniquely low overpotential of 215 mV. Moreover, the NiFe/Cu2O NWs/CF electrode can maintain a steady current density of 100 mA cm−2 for 50 h at an overpotential of 260 mV.
      PubDate: 2017-02-28T03:40:39.143646-05:
      DOI: 10.1002/cssc.201601884
       
  • Asymmetric Chemoenzymatic Reductive Acylation of Ketones Using a Combined
           Iron Catalyzed Hydrogenation-Racemization and Enzymatic Resolution Cascade
           
    • Authors: Magnus Rueping
      Abstract: A general and practical process for the conversion of pro-chiral ketones into the corresponding chiral acetates has been realized. An iron carbonyl complex is reported to catalyze the hydrogenation-dehydrogenation-hydrogenation of pro-chiral ketones. By merging the iron catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones as well as diketones, were reductively acylated. The corresponding products were isolated with high yields and enantioselectivities. The use of an iron catalyst together with molecular hydrogen as the hydrogen donor and readily available ethyl acetate as acyl donor make this cascade process highly interesting in terms of both economic value and environmental credentials.
      PubDate: 2017-02-28T02:45:27.389603-05:
      DOI: 10.1002/cssc.201700169
       
  • Honeycomb-like Nitrogen and Sulfur Dual-doped Hierarchical Porous Biomass
           Carbon for High-energy-density Lithium-sulfur Batteries
    • Authors: Manfang Chen; Shouxin Jiang, Cheng Huang, Xianyou Wang, Siyu Cai, Kaixiong Xiang, Yapeng Zhang, Jiaxi Xue
      Abstract: The honeycomb-like nitrogen and sulfur dual-doped hierarchical porous biomass carbon/sulfur composites (NSHPC/S) are successfully fabricated for high-energy-density lithium-sulfur batteries. The effects of N, S dual-doping on the structures and properties of the NSHPC/S composites are detailedly investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and charge/discharge tests. The results show that N, S dual-doping can not only introduce strong chemical adsorption and provide more active sites but also markedly enhance the electronic conductivity and hydrophilic properties of hierarchical porous biomass carbon, thereby significantly enhancing the utilization of sulfur and immobilizing the notorious polysulfide shuttle effect. Especially, the as-synthesized NSHPC-7/S exhibits high initial discharge capacity of 1204 mAh g-1 at 1.0 C and large reversible capacity of 952 mAh g-1 after 300 cycles at 0.5 C with an ultralow capacity fading rate of 0.08% per cycle even at high sulfur content (85 wt%) and high active material areal mass loading (2.8 mg cm-2) for the application of high-energy-density Li-S batteries.
      PubDate: 2017-02-25T05:25:26.653196-05:
      DOI: 10.1002/cssc.201700050
       
  • An eco-friendly, tunable and scalable method for producing porous
           functional nanomaterials designed using molecular interactions
    • Authors: Joseph R. H. Manning; Thomas Yip, Alessia Centi, Miguel Jorge, Siddharth V Patwardhan
      Abstract: Abstract: Despite significant improvements in the synthesis of templated silica materials, post-synthesis purification remains highly expensive and render the materials industrially unviable. In this study we address this issue for porous bioinspired silica, developing a rapid room-temperature solution method for complete extraction of organic additives. Using elemental analysis and N2 and CO2 adsorption, we demonstrate the ability to both purify and controllably tailor the composition, porosity and surface chemistry of bioinspired silica in a single step. For the first time we have modelled the extraction using molecular dynamics, revealing the removal mechanism is dominated by surface-charge interactions. We extend this to other additive chemistry, leading to a wider applicability of the method to other materials. Finally we estimate the environmental benefits of our new method compared with previous purification techniques, demonstrating significant improvements in sustainability.
      PubDate: 2017-02-24T16:20:23.308555-05:
      DOI: 10.1002/cssc.201700027
       
  • Influence of catalyst acid/base properties in acrolein production by
           oxidative coupling of ethanol and methanol
    • Authors: Aleksandra Lilic; Simona Bennici, Jean-Fraçois Devaux, Jean-Luc Dubois, Aline Auroux
      Abstract: Oxidative coupling of methanol and ethanol represents a new route to produce acrolein. In this work, the overall reaction was decoupled in 2 steps, the oxidation and the aldolization, using two consecutive reactors in order to investigate the role of acid/base properties of silica-supported oxide catalysts. The oxidation of a mixture of methanol and ethanol to formaldehyde and acetaldehyde was performed on a FeMoOx catalyst, then the products mixture was sent in a second reactor, without intermediate separation, where the aldol-condensation and dehydration to acrolein were carried out on the supported oxides. The impact of the acid-base properties on the selectivity towards acrolein has been, for the first time, investigated in oxidizing conditions. The acid-base properties of the catalysts have been investigated by NH3, SO2 and methanol adsorption microcalorimetry. MgO/SiO2 catalyst was the most active in acrolein production thanks to an appropriate ratio of basic to acidic sites.
      PubDate: 2017-02-24T13:20:27.437242-05:
      DOI: 10.1002/cssc.201700230
       
  • The Chemical Route to a Carbon Dioxide Neutral World
    • Authors: Johan A. Martens; Annemie Bogaerts, Norbert De Kimpe, Pierre A. Jacobs, Guy B. Marin, Korneel Rabaey, Mark Saeys, Sebastian Verhelst
      Abstract: Excessive CO2 emissions in the atmosphere from anthropogenic activity can be divided into point sources and diffuse sources. The capture of CO2 from flue gases of large industrial installations and its conversion into fuels and chemicals with fast catalytic processes seems technically possible. Some emerging technologies are already being demonstrated on an industrial scale. Others are still being tested on a laboratory or pilot scale. These emerging chemical technologies can be implemented in a time window ranging from 5 to 20 years. The massive amounts of energy needed for capturing processes and the conversion of CO2 should come from low-carbon energy sources, such as tidal, geothermal, and nuclear energy, but also, mainly, from the sun. Synthetic methane gas that can be formed from CO2 and hydrogen gas is an attractive renewable energy carrier with an existing distribution system. Methanol offers advantages as a liquid fuel and is also a building block for the chemical industry. CO2 emissions from diffuse sources is a difficult problem to solve, particularly for CO2 emissions from road, water, and air transport, but steady progress in the development of technology for capturing CO2 from air is being made. It is impossible to ban carbon from the entire energy supply of mankind with the current technological knowledge, but a transition to a mixed carbon–hydrogen economy can reduce net CO2 emissions and ultimately lead to a CO2-neutral world.No time to spare: Timing in the carbon cycle suggests large-scale chemical processes in which CO2 is chemically reduced to fuel within seconds are needed to close the carbon cycle and to avoid the emission of greenhouse gases. This type of cycle, in which CO2 is formed and converted back on the same timescale, is a sustainable solution for achieving a CO2-neutral world.
      PubDate: 2017-02-24T07:21:45.988519-05:
      DOI: 10.1002/cssc.201601051
       
  • p-cymene as a solvent for olefin metathesis: matching efficiency and
           sustainability
    • Authors: Eduardo N. dos Santos; Artur V. Granato, Alexandra G. Santos
      Abstract: The underexploited, biorenewable, p-cymene is employed as a solvent for the metathesis of various substrates. p-cymene is a nontoxic compound that can be obtained in large amounts from side product of cellulose and citrus industry. For the cross-metathesis of estragole with methyl acrylate, this solvent prevents the consecutive double-bond isomerization of the product and gives the best yield of all solvents tested. Undesired consecutive isomerization is a major problem for many substrates in olefin metathesis, including pharmaceutical precursors, and the use of p-cymene as solvent may be a way to prevent it. This solvent presented a better performance for metathesis than toluene for three substrates tested in this work, matching its performance for other two substrates.
      PubDate: 2017-02-23T08:20:32.506694-05:
      DOI: 10.1002/cssc.201700116
       
  • Integration of Platinum Group Metal-Free Catalysts and Bilirubin Oxidase
           into a Hybrid Material for Oxygen Reduction: Interplay of Chemistry and
           Morphology
    • Authors: Santiago Rojas-Carbonell; Sofia Babanova, Alexey Serov, Kateryna Artyushkova, Michael J. Workman, Carlo Santoro, Alex Mirabal, Scott Calabrese Barton, Plamen Atanassov
      Abstract: Catalytic activity toward the oxygen reduction reaction (ORR) of platinum group metal-free (PGM-free) electrocatalysts integrated with an enzyme (bilirubin oxidase, BOx) in neutral media was studied. The effects of chemical and morphological characteristics of PGM-free materials on the enzyme enhancement of the overall ORR kinetics was investigated. The surface chemistry of the PGM-free catalyst was studied using X-ray Photoelectron Spectroscopy. Catalyst surface morphology was characterized using two independent methods: length-scale specific image analysis and nitrogen adsorption. Good agreement of macroscopic and microscopic morphological properties was found. Enhancement of ORR activity by the enzyme is influenced by chemistry and surface morphology of the catalyst itself. Catalysts with a higher nitrogen content, specifically pyridinic moieties, showed the greatest enhancement. Furthermore, catalysts with a higher fraction of surface roughness in the range of 3–5 nm exhibited greater performance enhancement than catalysts lacking features of this size.Outside the BOx: The enhancement of the electrochemical activity toward oxygen reduction reaction with the addition of an enzyme (bilirubin oxidase, BOx) to a platinum group metal-free (PGM-free) catalyst is shown. The influence of chemistry and morphology of the PGM-free materials is found to have an impact in the level of enhancement of the hybrid catalyst.
      PubDate: 2017-02-23T05:45:42.654954-05:
      DOI: 10.1002/cssc.201601822
       
  • CO2 Catalysis
    • Authors: Arjan W. Kleij; Michael North, Atsushi Urakawa
      Abstract: Out of thin air: In this Editorial, the Guest Editors introduce a Special Issue on Carbon Dioxide Conversion Catalysis, discuss its importance in modern chemical processes, and highlight a few examples of its use in industry, such as the synthesis of cyclic carbonates and the conversion of CO2 into fuels.
      PubDate: 2017-02-20T08:55:23.40969-05:0
      DOI: 10.1002/cssc.201700218
       
  • An improved strategy for the synthesis of ethylene glycol via
           oxamate-mediated catalytic hydrogenation
    • Authors: Anilkumar Satapathy; Sandip T. Gadge, Bhalchandra Mahadeo Bhanage
      Abstract: Present study reports an improved approach for the preparation of ethylene glycol (EG) by using carbon monoxide as C1 chemical via oxidative carbonylation and hydrogenation sequence. In the first step oxamates have been synthesized by oxidative cross double carbonylation of piperidine and ethanol using Pd/C catalyst under phosphine ligand-free conditions and subsequently hydrogenated by Milstein catalyst. The presented stepwise oxamate-mediated coupling provides the basis for a new strategy for synthesis of EG by selective upgrading of C1 chemicals.
      PubDate: 2017-02-20T08:15:25.726564-05:
      DOI: 10.1002/cssc.201700157
       
  • Metal–Phenolic Carbon Nanocomposites for Robust and Flexible
           Energy-Storage Devices
    • Authors: Jun Young Oh; Yeonsu Jung, Young Shik Cho, Jaeyoo Choi, Ji Ho Youk, Nina Fechler, Seung Jae Yang, Chong Rae Park
      Abstract: Future electronics applications such as wearable electronics depend on the successful construction of energy-storage devices with superior flexibility and high electrochemical performance. However, these prerequisites are challenging to combine: External forces often cause performance degradation, whereas the trade-off between the required nanostructures for strength and electrochemical performance only results in diminished energy storage. Herein, a flexible supercapacitor based on tannic acid (TA) and carbon nanotubes (CNTs) with a unique nanostructure is presented. TA was self-assembled on the surface of the CNTs by metal–phenolic coordination bonds, which provides the hybrid film with both high strength and high pseudocapacitance. Besides 17-fold increased mechanical strength of the final composite, the hybrid film simultaneously exhibits excellent flexibility and volumetric capacitance.Flexible electrodes: A metal–phenolic carbon nanocomposite film is designed and assembled by metal–organic coordination. The phenolic groups of tannic acid facilitate the aqueous dispersion and cross-linking of carbon nanotubes and provide redox-active sites for pseudocapacitance. The resulting materials exhibit high strength, flexibility, and stable volumetric capacitance under bending conditions.
      PubDate: 2017-02-20T02:55:32.554322-05:
      DOI: 10.1002/cssc.201601615
       
  • A Simple and Mild Approach for the Synthesis of p-Xylene from Bio-based
           2,5-Dimethyfuran by Metal Triflates in Ionic Liquids
    • Authors: Lingli Ni; Jiayu Xin, Huixian Dong, Xingmei Lu, Xiaomin Liu, Suojiang Zhang
      Abstract: The production of aromatic platform chemicals from biomass-derived feedstocks is of great importance in biomass conversion. However, developments of effective routes with simple steps and mild conditions are still challenging. In this work, we reported a novel route to directly synthesize p-xylene from 2,5-dimethylfuran and acrylic acid by Sc(OTf)3 in [Emim]NTf2 at mild conditions, overall 63% selectivity of p-xylene and 78% selectivity of aromatics were obtained at 90% conversion of 2,5-dimethylfuran by enhancing the dehydration and introducing an extra one-pot decarboxylation process. Furthermore, various dienes and dienophiles were employed as reactants to extend the substrate scope and the aromatics were obtained with moderate yields, which proved the potential of the method to be a generic approach for the conversion of bio-based furanics into renewable aromatics.
      PubDate: 2017-02-11T10:25:26.762649-05:
      DOI: 10.1002/cssc.201700020
       
  • A sustainable one-pot two-enzymes synthesis of naturally occurring
           arylalkyl glucosides
    • Authors: Ivan Bassanini; Jana Krejzova, Walter Panzeri, Daniela Monti, Vladimir Kren, Sergio Riva
      Abstract: A sustainable, convenient and scalable one-pot two-enzymes method for the glucosylation of arylalkyl alcohols has been developed. The reaction scheme is based on a transrutinosylation catalyzed by a rutinosidase from A. niger using the cheap commercially available natural flavonoid rutin as glycosyl donor, followed by a selective 'trimming' of the rutinoside unit catalyzed by a rhamnosidase from A. terreus. The process has been validated with the syntheses of several natural bioactive glucosides, that could be isolated in up to 75 % yield avoiding silica gel chromatography.
      PubDate: 2017-02-10T07:25:37.820292-05:
      DOI: 10.1002/cssc.201700136
       
  • Feasibility of a supporting salt free non-aqueous redox flow battery
           utilizing ionic active materials
    • Authors: Jarrod Milshtein; Sydney Fisher, Tanya Breault, Levi Thompson, Fikile Brushett
      Abstract: Non-aqueous redox flow batteries (NAqRFBs) are promising devices for grid-scale energy storage, however, high projected prices could limit commercial prospects. One price reduction route is to minimize or eliminate the expensive supporting salts typically employed in NAqRFBs. We demonstrate the feasibility of a flow cell operating in the absence of supporting salt, utilizing ionic active species. These ionic species possess high conductivities in acetonitrile (12 - 19 mS cm-1), and cycle at 20 mA cm-2 with energy efficiencies (> 75%) comparable to state-of-the-art NAqRFBs employing high concentrations of supporting salt. A chemistry-agnostic techno-economic analysis highlights the possible cost savings of minimizing salt content in a NAqRFB. This paper offers the first demonstration of a NAqRFB operating without supporting salt. The associated design principles can guide the development of future active species and could make NAqRFBs competitive with their aqueous counterparts.
      PubDate: 2017-02-08T11:20:37.390436-05:
      DOI: 10.1002/cssc.201700028
       
  • Selective production of 2-methylfuran by gas phase hydrogenation of
           furfural on copper incorporated by complexing to mesoporous silica
           catalysts
    • Authors: Carmen Pilar Jiménez-Gómez; Juan A. Cecilia, Ramón Moreno-Tost, Pedro Maireles-Torres
      Abstract: Copper species have been incorporated to a mesoporous silica by complexing with amino group of dodecylamine molecules, used as structure-directing agent in the synthesis. A series of Cu/SiO2 catalysts, with copper loadings from 2.5 to 20 wt%, has been synthesized and evaluated in the gas phase hydrogenation of furfural. The most suitable catalytic performance, in terms of 2-methylfuran yield, has been found for intermediate copper content (10 wt%). In this sense, the 10Cu-MS catalyst, at a reaction temperature of 210ºC, after 5 h of time-on-stream, exhibits a 2-methylfuran yield higher than 95 mol%, with a H2:FUR molar ratio of 11.5 and a WHSV of 1.5 h-1. After 14 h of TOS, this catalyst still shows a yield of 80 mol%. In all cases, the carbonaceous deposits on the external surface were the cause of the catalyst deactivation, although sintering of copper particles was observed for higher copper loadings. The best catalytic performance is found for an intermediate copper loading (10 wt%Cu), where a suitable balance between resistance to sintering and tendency to form carbonaceous deposits, responsible of catalyst deactivation, is achieved.
      PubDate: 2017-02-06T08:20:58.945438-05:
      DOI: 10.1002/cssc.201700086
       
  • Catalytic biodiesel production mediated by amino acid-based protic salts
    • Authors: Jingbo Li; Zheng Guo
      Abstract: Hetero-/homo-geneous acid catalysts are effective catalysts for biodiesel produced from oils containing high free fatty acids. The protic salts synthesized from natural amino acids were examined for their catalytic activity and efficiency for esterification of oleic acid after structural identification and characterization. The melting points of the protic salts were measured. In the esterification reaction of oleic acid with methanol, [Asp][NO3] performed the best, correlating to its higher Hammett acidity. The optimal reaction conditions for esterification of oleic acid to achieve 97% biodiesel yield were: temperature 70 °C, catalyst 10% (w/w, on oleic acid basis), methanol to oleic acid ratio 7.5:1, and 5 h. [Asp][NO3] could be a generally good catalyst for esterification of oleic acid with alcohols with chain length up to 6. The biodiesel yield of 93.86% was obtained from palm fatty acid distillate, implying potential industrial application of the catalyst. Kinetic study indicated that the reaction followed a pseudo-first order reaction, with activation energy and pre-exponential of 57.36 kJ/mol and 44.24×105 min-1. In conclusion, the aspartic acid derived protic salt is a promising, operational simply, sustainable, renewable, and possible biodegradable catalyst for converting high content of free fatty acids into biodiesel.
      PubDate: 2017-02-06T06:15:34.359201-05:
      DOI: 10.1002/cssc.201700026
       
  • High-performance supported Ir-oxohydroxide water oxidation
           electrocatalysts
    • Authors: Cyriac Massue; Verena Pfeifer, Xing Huang, Johannes Noack, Andrey Tarasov, Sebastien Cap, Robert Schlögl
      Abstract: The synthesis of a highly active and yet stable electrocatalyst for the anodic oxygen evolution reaction (OER) remains a major challenge for acidic water splitting on an industrial scale. Addressing this challenge, we obtained an outstanding high-performance OER-electrocatalyst by loading Ir on conductive antimony-doped tin oxide (ATO)-nanoparticles via a microwave (MW)-supported hydrothermal route. The obtained Ir-phase was identified as an XRD-amorphous, highly hydrated Ir(III/IV)-oxohydroxide. In order to identify chemical and structural features responsible for the high activity and exceptional stability under acidic OER-conditions at loadings as low as 20 μg(Ir) cm-2, we used stepwise thermal treatment to gradually alter the XRD-amorphous Ir-phase via dehydroxylation and crystallization of IrO2. This resulted in dramatic depletion of OER-performance, indicating that the outstanding electrocatalytic properties of the MW-produced Ir(III/IV)-oxohydroxide are prominently linked to the nature of the produced Ir-phase. This finding is in contrast with the often reported stable but poor OER-performance of crystalline IrO2-based compounds produced via more classical calcination routes. Our investigation demonstrates the immense potential of Ir-oxohydroxide-based OER electrocatalysts for stable high-current water electrolysis under acidic conditions.
      PubDate: 2017-02-05T22:20:59.370129-05:
      DOI: 10.1002/cssc.201601817
       
  • Microwave Assisted Synthesis of Stable and Highly Active Ir-oxohydroxides
           for Electrochemical Oxidation of Water
    • Authors: Cyriac Massue; Xing Huang, Andrey Tarasov, Chinmoy Ranjan, Sebastien Cap, Robert Schlögl
      Abstract: Water splitting for hydrogen production in acidic media has been limited by the poor stability of the anodic electrocatalyst devoted to the oxygen evolution reaction (OER). To help circumvent this problem we have synthesized a class of novel Ir-oxohydroxides via rapid microwave-supported hydrothermal synthesis, which bridge the gap between electrodeposited amorphous IrOx-films and crystalline IrO2-electrocatalysts prepared via calcination routes. For electrode loadings two orders of magnitude below current standards, the synthesized compounds present an unrivalled combination of high activity and stability under commercially relevant OER-conditions in comparison to reported benchmarks, without any need for pre-treatment. The best compound achieved a lifetime 33 times longer than the best commercial Ir-benchmark. Thus, the reported efficient synthesis of an Ir-oxohydroxide phase with superior intrinsic OER-performance constitutes a major step towards the targeted design of cost-efficient Ir-based OER-electrocatalysts for acidic media.
      PubDate: 2017-02-05T22:20:51.914732-05:
      DOI: 10.1002/cssc.201601864
       
  • Solar cells materials by design: Hybrid pyroxene corner-sharing VO4
           tetrahedral chains
    • Authors: Fedwa El-Mellouhi; Akinlolu Akande, Carlo Motta, Sergey Rashkeev, Golibjon Berdiyorov, Mohamed El-Amine El Amine madjet, Asma Marzouk, El Tayeb Bentria, Stefano Sanvito, Sabre Kais, Fahhad Hussain Al Harbi
      Abstract: Hybrid organic-inorganic frameworks provide numerous combinations of materials with a widerange of structural and electronic properties, which enable their use in various applications. Inrecent years, some of these hybrid materials (especially lead-based halide perovskites) have beensuccessfully used for the development of highly ecient solar cells. The large variety of possiblehybrid materials inspired us into the search of other organic-inorganic frameworks, which may exhibitenhanced performance when compared to conventional lead-halide perovskites. In this work wedesign a new class of low-dimensional hybrid oxides for photovoltaic applications by using electronicstructure calculations in combination with analysis from existing materials databases. We focuson oxide vanadium pyroxenes (tetrahedron-based frameworks), mainly due to their high stabilityand non-toxicity. We have screened pyroxenes with dierent cations [A] and performed detailedcomputational studies of their structural, electronic, optical and transport properties. We foundthat low-dimensional hybrid vanadate pyroxenes [A]VO3 (with molecular cations [A] and cornersharedVO4 tetrahedral chains) can satisfy all physical requirements needed to develop an ecientsolar cell (a bandgap of 1.0{1.7 eV, strong light absorption and good electronic transport properties).
      PubDate: 2017-02-05T22:20:48.749555-05:
      DOI: 10.1002/cssc.201700121
       
  • Ultrathin mesoporous RuCo2O4 nanoflakes: A novel advanced electrode for
           high performance asymmetric supercapacitors
    • Authors: Deepak Dubal; Nilesh Chodankar, Rudolf Holze, Do-Heyoung Kim, Pedro Gomez-Romero
      Abstract: A novel ruthenium cobalt oxide (RuCo2O4) with a unique marigold-like nanostructure leading to excellent performance as an advanced electrode material has been successfully prepared by a simple electrodeposition (potentiodynamic mode) method. The RuCo2O4 marigolds consist of numerous clusters of ultrathin mesoporous nanoflakes, leaving a large interspace between them to provide numerous electrochemically active sites. Strikingly, this unique marigold-like nanostructure provides excellent electrochemical performance in terms of high energy storing capacitance (1469 F/g at 6 A/g) with excellent rate proficiency and long-lasting operating cycling stability (around 91.3 % capacitance retention after 3000 cycles), confirming all mesoporous nanoflakes participate in the ultrafast electrochemical reactions. Furthermore, an asymmetric supercapacitor was assembled using RuCo2O4 (positive electrode) and activated carbon (AC) (negative electrode) with aqueous KOH electrolyte. The asymmetric design allows an upgraded potential range of 1.4 V, which further provides good energy density of 32.6 Wh/kg (1.1 mWh/cm3). More importantly, the cell delivers an energy density of 12.4 Wh/kg even at maximum power density of 3.2 kW/kg, which is noticeably superior to carbon-based symmetric systems.
      PubDate: 2017-02-03T06:05:45.144097-05:
      DOI: 10.1002/cssc.201700001
       
  • Cover Picture: Selective Hydrogenolysis of Glycerol to 1,3-Propanediol:
           Manipulating the Frustrated Lewis Pairs by Introducing Gold to Pt/WOx
           (ChemSusChem 5/2017)
    • Authors: Xiaochen Zhao; Jia Wang, Man Yang, Nian Lei, Lin Li, Baolin Hou, Shu Miao, Xiaoli Pan, Aiqin Wang, Tao Zhang
      Pages: 816 - 816
      Abstract: The Cover picture shows the selective hydrogenolysis of glycerol to 1,3-propanediol that was catalyzed by in situ-generated analogue of “Frustrated Lewis Pairs” (FLP) with the assistance of H2. The introduction of highly dispersed Au species to Pt/WOx catalysts can enhance the formation of this FLP structure, and results in simultaneously improved 1,3-propanediol selectivity (51.6%) and glycerol conversion (81.1%) under mild reaction conditions (1 MPa H2, 413 K). More details can be found in the Communication by Zhao et al. on page 819 in Issue 5, 2017 (
      DOI : 10.1002/cssc.201601503).
      PubDate: 2017-03-02T05:55:29.99258-05:0
       
  • Inside Cover: Lignin-Derived Thioacidolysis Dimers: Reevaluation, New
           Products, Authentication, and Quantification (ChemSusChem 5/2017)
    • Authors: Fengxia Yue; Fachuang Lu, Matt Regner, Runcang Sun, John Ralph
      Pages: 817 - 817
      Abstract: The Inside Cover picture shows the set of 12 newly synthesized, authenticated, and quantified thioacidolysis dimers released from a schematic guaiacyl lignin polymer showing the parent structures flanked by the cleavable β-ether units in cyan. Such dimers, quantified here for the first time, reflect the distribution of recalcitrant lignin units. Most had not been previously validated, one was previously misassigned and its correction resolves an analytical quandary, and important new β—β dimers have now been identified resolving the long-standing dilemma that they could not be found in softwood lignin analyses. More details can be found in the Communication by Yue et al. on page 830 in Issue 5, 2017 (
      DOI : 10.1002/cssc.201700101).
      PubDate: 2017-03-07T05:30:40.321919-05:
       
  • Selective Hydrogenolysis of Glycerol to 1,3-Propanediol: Manipulating the
           Frustrated Lewis Pairs by Introducing Gold to Pt/WOx
    • Authors: Xiaochen Zhao; Jia Wang, Man Yang, Nian Lei, Lin Li, Baolin Hou, Shu Miao, Xiaoli Pan, Aiqin Wang, Tao Zhang
      Pages: 818 - 818
      Abstract: Invited for this month′s cover is the group of Tao Zhang at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences. The image shows that Au promoter can simultaneously improve the glycerol conversion and 1,3-propanediol selectivity under relatively mild conditions, by enlarging the analogue of “Frustrated Lewis Pairs” with the assistance of H2. The Communication itself is available at 10.1002/cssc.201601503.“The Au promoter serves as “the magic bean”, little but powerful…” 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.201601503. View the Front Cover here: 10.1002/cssc.201700326.
      PubDate: 2017-03-07T05:30:46.23012-05:0
      DOI: 10.1002/cssc.201700325
       
  • Direct Synthesis of Renewable Dodecanol and Dodecane with Methyl Isobutyl
           Ketone over Dual-Bed Catalyst Systems
    • Authors: Xueru Sheng; Ning Li, Guangyi Li, Wentao Wang, Aiqin Wang, Yu Cong, Xiaodong Wang, Tao Zhang
      Pages: 825 - 829
      Abstract: For the first time, we demonstrated two integrated processes for the direct synthesis of dodecanol or 2,4,8-trimethylnonane (a jet fuel range C12-branched alkane) using methyl isobutyl ketone (MIBK) that can be derived from lignocellulose. The reactions were carried out in dual-bed continuous flow reactors. In the first bed, MIBK was selectively converted to a mixture of C12 alcohol and ketone. Over the Pd-modified magnesium– aluminium hydrotalcite (Pd-MgAl-HT) catalyst, a high total carbon yield (73.0 %) of C12 oxygenates can be achieved under mild conditions. In the second bed, the C12 oxygenates generated in the first bed were hydrogenated to dodecanol over a Ru/C catalyst or hydrodeoxygenated to 2,4,8-trimethylnonane over a Cu/SiO2 catalyst. The as-obtained dodecanol can be used as feedstock in the production of sodium dodecylsulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), which are widely used as surfactants or detergents. The asobtained 2,4,8-trimethylnonane can be blended into conventional jet fuel without hydroisomerization.Dual-bed catalysis: For the first time, dodecanol and jet fuel range C12-branched alkane (2,4,8-trimethylnonane) are directly synthesized with high carbon yield (∼70 %) by using dual-bed catalyst systems with hydrogen and methyl isobutyl ketone (MIBK) that can be derived from lignocellulose.
      PubDate: 2017-01-18T05:40:24.467744-05:
      DOI: 10.1002/cssc.201601563
       
  • Lignin-Derived Thioacidolysis Dimers: Reevaluation, New Products,
           Authentication, and Quantification
    • Authors: Fengxia Yue; Fachuang Lu, Matt Regner, Runcang Sun, John Ralph
      Pages: 830 - 835
      Abstract: Lignin structural studies play an essential role both in understanding the development of plant cell walls and for valorizing lignocellulosics as renewable biomaterials. Dimeric products released by selectively cleaving β–aryl ether linkages between lignin units reflect the distribution of recalcitrant lignin units, but have been neither absolutely defined nor quantitatively determined. Here, 12 guaiacyl-type thioacidolysis dimers were identified and quantified using newly synthesized standards. One product previously attributed to deriving from β–1-coupled units was established as resulting from β–5 units, correcting an analytical quandary. Another longstanding dilemma, that no β–β dimers were recognized in thioacidolysis products from gymnosperms, was resolved with the discovery of two such authenticated compounds. Individual GC response factors for each standard compound allowed rigorous quantification of dimeric products released from softwood lignins, affording insight into the various interunit-linkage distributions in lignins and thereby guiding the valorization of lignocellulosics.A closer look at lignin structures: New insights are gained from authenticating and quantifying dimeric thioacidolysis products using various synthesized standard guaiacyl-type dimers. A longstanding compound assignment error is corrected, the dilemma of observing no β–β products from pinoresinol structures from softwood lignins is resolved, and the combinatorial nature of lignification is confirmed.
      PubDate: 2017-02-15T07:10:32.458933-05:
      DOI: 10.1002/cssc.201700101
       
  • NHC-Ag/Pd-Catalyzed Reductive Carboxylation of Terminal Alkynes with CO2
           and H2: A Combined Experimental and Computational Study for Fine-Tuned
           Selectivity
    • Authors: Dingyi Yu; Feng Zhou, Diane S. W. Lim, Haibin Su, Yugen Zhang
      Pages: 836 - 841
      Abstract: Reductive carboxylation of terminal alkynes utilizing CO2 and H2 as reactants is an interesting and challenging transformation. Theoretical calculations indicated it would be kinetically possible to obtain cinnamic acid, the reductive carboxylation product, from phenylacetylene in a CO2/H2 system with an N-heterocyclic carbene (NHC)-supported Ag/Pd bimetallic catalysts through competitive carboxylation/hydrogenation cascade reactions in one step. These calculations were verified experimentally with a poly-NHC-supported Ag/Pd catalyst. By tuning the catalyst composition and reaction temperature, phenylacetylene was selectively converted to cinnamic acid, hydrocinnamic acid, or phenylpropiolic acid in excellent yields.From theory to practice: Theoretical calculation and experimental development are combined for reductive carboxylation of terminal alkynes utilizing CO2 and H2 as reactants. In the system with phenylacetylene, CO2/H2, and N-heterocyclic carbene-supported Ag/Pd bimetallic catalysts, cinnamic acid, hydrocinnamic acid, or phenylpropiolic acid are selectively produced in excellent yields under fine-tuned conditions.
      PubDate: 2017-02-10T03:11:06.425925-05:
      DOI: 10.1002/cssc.201601785
       
  • Selective Hydrogenation of Nitriles to Primary Amines by using a Cobalt
           Phosphine Catalyst
    • Authors: Rosa Adam; Charles Beromeo Bheeter, Jose R. Cabrero-Antonino, Kathrin Junge, Ralf Jackstell, Matthias Beller
      Pages: 842 - 846
      Abstract: A general procedure for the catalytic hydrogenation of nitriles to primary amines by using a non-noble metal-based system is presented. Co(acac)3 in combination with tris[2-(dicyclohexylphosphino)ethyl]phosphine efficiently catalyzes the selective hydrogenation of a wide range of (hetero)aromatic and aliphatic nitriles to give the corresponding amines.Cobalt catalyzes it: A general procedure for the selective hydrogenation of (hetero)aromatic or aliphatic nitriles catalyzed by a cobalt-based system is described. A wide range of primary amines are synthesized in 61–99 % yield. Use of the tetradentate ligand tris[2-(dicyclohexylphosphino)ethyl]phosphine is key for the activity of the system.
      PubDate: 2017-01-23T05:20:55.51612-05:0
      DOI: 10.1002/cssc.201601843
       
  • Low-Energy Catalytic Electrolysis for Simultaneous Hydrogen Evolution and
           Lignin Depolymerization
    • Authors: Xu Du; Wei Liu, Zhe Zhang, Arie Mulyadi, Alex Brittain, Jian Gong, Yulin Deng
      Pages: 847 - 854
      Abstract: Here, a new proton-exchange-membrane electrolysis is presented, in which lignin was used as the hydrogen source at the anode for hydrogen production. Either polyoxometalate (POM) or FeCl3 was used as the catalyst and charge-transfer agent at the anode. Over 90 % Faraday efficiency was achieved. In a thermal-insulation reactor, the heat energy could be maintained at a very low level for continuous operation. Compared to the best alkaline–water electrolysis reported in literature, the electrical-energy consumption could be 40 % lower with lignin electrolysis. At the anode, the Kraft lignin (KL) was oxidized to aromatic chemicals by POM or FeCl3, and reduced POM or Fe ions were regenerated during the electrolysis. Structure analysis of the residual KL indicated a reduction of the amount of hydroxyl groups and the cleavage of ether bonds. The results suggest that POM- or FeCl3-mediated electrolysis can significantly reduce the electrolysis energy consumption in hydrogen production and, simultaneously, depolymerize lignin to low-molecular-weight value-added aromatic chemicals.Two birds with one stone: A new direct lignin proton-exchange-membrane electrolysis can significantly reduce the electrolysis energy consumption in hydrogen production and, simultaneously, depolymerize lignin to value-added aromatic chemicals. Lignin is used as the aromatics and hydrogen source at the anode. Either polyoxometalate or FeCl3 is used as the catalyst and charge-transfer agent at the anode.
      PubDate: 2017-02-17T05:12:01.260379-05:
      DOI: 10.1002/cssc.201601685
       
  • In Situ Raman Spectroscopic Studies on Concentration of Electrolyte Salt
           in Lithium-Ion Batteries by Using Ultrafine Multifiber Probes
    • Authors: Toshiro Yamanaka; Hiroe Nakagawa, Shigetaka Tsubouchi, Yasuhiro Domi, Takayuki Doi, Takeshi Abe, Zempachi Ogumi
      Pages: 855 - 861
      Abstract: Lithium-ion batteries have attracted considerable attention due to their high power density. The change in concentration of salt in the electrolyte solution in lithium-ion batteries during operation causes serious degradation of battery performance. Herein, a new method of in situ Raman spectroscopy with ultrafine multifiber probes was developed to simultaneously study the concentrations of ions at several different positions in the electrolyte solution in deep narrow spaces between the electrodes in batteries. The total amount of ions in the electrolyte solution clearly changed during operation due to the low permeability of the solid–electrolyte interphase (SEI) at the anode for Li+ permeation. The permeability, which is a key factor to achieve high battery performance, was improved (enhanced) by adding film-forming additives to the electrolyte solution to modify the properties of the SEI. The results provide important information for understanding and predicting phenomena occurring in a battery and for designing a superior battery. The present method is useful for analysis in deep narrow spaces in other electrochemical devices, such as capacitors.Ions in the deep: The total amount of ions in an electrolyte solution in a lithium-ion battery changes during operation. The change can be used as an indicator of the permeability of the solid–electrolyte interphase (SEI) at the anode for Li+ permeation, which is a key factor to achieve high battery performance. The permeability is improved by adding film-forming additives to the electrolyte to modify the properties of the SEI.
      PubDate: 2017-02-14T03:35:41.273147-05:
      DOI: 10.1002/cssc.201601473
       
  • A Robust Molecular Catalyst Generated In Situ for Photo- and
           Electrochemical Water Oxidation
    • Authors: Hussein A. Younus; Nazir Ahmad, Adeel H. Chughtai, Matthias Vandichel, Michael Busch, Kristof Van Hecke, Mekhman Yusubov, Shaoxian Song, Francis Verpoort
      Pages: 862 - 875
      Abstract: Water splitting is the key step towards artificial photosystems for solar energy conversion and storage in the form of chemical bonding. The oxidation of water is the bottle-neck of this process that hampers its practical utility; hence, efficient, robust, and easy to make catalytic systems based on cheap and earth-abundant materials are of exceptional importance. Herein, an in situ generated cobalt catalyst, [CoII(TCA)2(H2O)2] (TCA=1-mesityl-1,2,3-1H-triazole-4-carboxylate), that efficiently conducts photochemical water oxidation under near-neutral conditions is presented. The catalyst showed high stability under photolytic conditions for more than 3 h of photoirradiation. During electrochemical water oxidation, the catalytic system assembled a catalyst film, which proved not to be cobalt oxide/hydroxide as normally expected, but instead, and for the first time, generated a molecular cobalt complex that incorporated the organic ligand bound to cobalt ions. The catalyst film exhibited a low overpotential for electrocatalytic water oxidation (360 mV) and high oxygen evolution peak current densities of 9 and 2.7 mA cm−2 on glassy carbon and indium-doped tin oxide electrodes, respectively, at only 1.49 and 1.39 V (versus a normal hydrogen electrode), respectively, under neutral conditions. This finding, exemplified on the in situ generated cobalt complex, might be applicable to other molecular systems and suggests that the formation of a catalytic film in electrochemical water oxidation experiments is not always an indication of catalyst decomposition and the formation of nanoparticles.Finding active catalytic species: An in situ generated cobalt catalyst efficiently conducts photo- and electrochemical water oxidation under near-neutral conditions. This work sheds light upon the ability to directly assemble molecular metal–organic catalyst films on the surface of different conducting electrodes for the potential molecular engineering of cobalt-based electrocatalytic films.
      PubDate: 2017-02-21T10:31:53.953002-05:
      DOI: 10.1002/cssc.201601477
       
  • Decomposition of Imidazolium-Based Ionic Liquids in Contact with Lithium
           Metal
    • Authors: Paulo Schmitz; Rene Jakelski, Marcelina Pyschik, Kirsi Jalkanen, Sascha Nowak, Martin Winter, Peter Bieker
      Pages: 876 - 883
      Abstract: Ionic liquids (ILs) are considered to be suitable electrolyte components for lithium-metal batteries. Imidazolium cation based ILs were previously found to be applicable for battery systems with a lithium-metal negative electrode. However, herein it is shown that, in contrast to the well-known IL N-butyl-N-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide ([Pyr14][TFSI]), 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C2MIm][TFSI]) and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C4MIm][TFSI]) are chemically unstable versus metallic lithium. A lithium-metal sheet was immersed in pure imidazolium-based IL samples and aged at 60 °C for 28 days. Afterwards, the aged IL samples were investigated to deduce possible decomposition products of the imidazolium cation. The chemical instability of the ILs in contact with lithium metal and a possible decomposition starting point are shown for the first time. Furthermore, the investigated imidazolium-based ILs can be utilized for lithium-metal batteries through the addition of the solid–electrolyte interphase (SEI) film-forming additive fluoroethylene carbonate.Effects of surface exposure: The chemical instability of imidazolium-based ionic liquids (ILs) in contact with lithium metal is discussed. After aging the ILs in contact with a lithium-metal sheet, possible decomposition products are analyzed. Furthermore, stable cycling behavior in lithium-metal batteries occurs through the addition of the solid–electrolyte interphase film-forming additive fluoroethylene carbonate.
      PubDate: 2017-02-20T08:55:29.387253-05:
      DOI: 10.1002/cssc.201601496
       
  • Strategy for Extending the Stability of Bio-oil-Derived Phenolic Oligomers
           by Mild Hydrotreatment with Ionic-Liquid-Stabilized Nanoparticles
    • Authors: Kwang Ho Kim; Robert C. Brown, Tannon Daugaard, William F. Tivol, Manfred Auer, Blake Simmons, Seema Singh
      Pages: 884 - 893
      Abstract: The development of catalytic transformations and processes is essential to utilize bio-oil and lignin derivatives. Metal nanoparticles (M-NPs) stabilized in ionic liquids (ILs) are promising for the catalytic hydrotreatment of bio-oil because the properties of the catalyst system can be customized by combining the appropriate IL and metal nanoparticles. Herein, we demonstrate an experimental approach to stabilize lignin-derived phenolics isolated from bio-oil with ruthenium NPs stabilized by an ionic copolymer in 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]). The mild hydrotreatment of phenolic oligomers (POs) was performed with the synthesized M-NP catalyst at 100 °C for 6 h. Hydrotreatment of the POs resulted in enhanced thermal stability of the POs by as much as a factor of three, as determined by the aging index and by reducing reactive functionalities, which was also confirmed by NMR spectroscopy and GC analysis. The results support our hypothesis that M-NPs stabilized in ILs can effectively stabilize POs under mild conditions, which could be applicable to any lignin-derived phenolic.Seeking treatment: Ruthenium nanoparticles stabilized in ionic liquid are prepared for the mild hydrotreatment of phenolic oligomers obtained from bio-oil. The hydrotreated phenolic oligomers show enhanced thermal stability.
      PubDate: 2017-02-17T03:55:30.146241-05:
      DOI: 10.1002/cssc.201601515
       
  • Sunlight-Dependent Hydrogen Production by Photosensitizer/Hydrogenase
           Systems
    • Authors: David Adam; Lisa Bösche, Leonardo Castañeda-Losada, Martin Winkler, Ulf-Peter Apfel, Thomas Happe
      Pages: 894 - 902
      Abstract: We report a sustainable in vitro system for enzyme-based photohydrogen production. The [FeFe]-hydrogenase HydA1 from Chlamydomonas reinhardtii was tested for photohydrogen production as a proton-reducing catalyst in combination with eight different photosensitizers. Using the organic dye 5-carboxyeosin as a photosensitizer and plant-type ferredoxin PetF as an electron mediator, HydA1 achieves the highest light-driven turnover number (TONHydA1) yet reported for an enzyme-based in vitro system (2.9×106 mol(H2) mol(cat)−1) and a maximum turnover frequency (TOFHydA1) of 550 mol(H2) mol(HydA1)−1 s−1. The system is fueled very effectively by ambient daylight and can be further simplified by using 5-carboxyeosin and HydA1 as a two-component photosensitizer/biocatalyst system without an additional redox mediator.Lighten up: We investigate the photohydrogen production of the xanthene dye 5-carboxyeosin and the [FeFe]-hydrogenase of Chlamydomonas reinhardtii. The three-component system is effectively fueled by ambient sunlight on two typical winter days in February.
      PubDate: 2017-02-09T07:40:56.099675-05:
      DOI: 10.1002/cssc.201601523
       
  • Mechanism of Water Oxidation Catalyzed by a Mononuclear Manganese Complex
    • Authors: Ying-Ying Li; Ke Ye, Per E. M. Siegbahn, Rong-Zhen Liao
      Pages: 903 - 911
      Abstract: The design and synthesis of biomimetic Mn complexes to catalyze oxygen evolution is a very appealing goal because water oxidation in nature employs a Mn complex. Recently, the mononuclear Mn complex [LMnII(H2O)2]2+ [1, L=Py2N(tBu)2, Py=pyridyl] was reported to catalyze water oxidation electrochemically at an applied potential of 1.23 V at pH 12.2 in aqueous solution. Density functional calculations were performed to elucidate the mechanism of water oxidation promoted by this catalyst. The calculations showed that 1 can lose two protons and one electron readily to produce [LMnIII(OH)2]+ (2), which then undergoes two sequential proton-coupled electron-transfer processes to afford [LMnVOO]+ (4). The O−O bond formation can occur through direct coupling of the two oxido ligands or through nucleophilic attack of water. These two mechanisms have similar barriers of approximately 17 kcal mol−1. The further oxidation of 4 to generate [LMnVIOO]2+ (5), which enables O−O bond formation, has a much higher barrier. In addition, ligand degradation by C−H activation has a similar barrier to that for the O−O bond formation, and this explains the relatively low turnover number of this catalyst.Water works: The mechanism of water oxidation catalyzed by a mononuclear Mn complex is investigated through DFT calculations. The O−O bond formation can occur through oxo–oxo coupling or nucleophilic water attack because these processes have similar barriers.
      PubDate: 2017-02-14T03:25:29.226984-05:
      DOI: 10.1002/cssc.201601538
       
  • Waste-to-Chemicals for a Circular Economy: The Case of Urea Production
           (Waste-to-Urea)
    • Authors: Elena Antonetti; Gaetano Iaquaniello, Annarita Salladini, Luca Spadaccini, Siglinda Perathoner, Gabriele Centi
      Pages: 912 - 920
      Abstract: The economics and environmental impact of a new technology for the production of urea from municipal solid waste, particularly the residue-derived fuel (RdF) fraction, is analyzed. Estimates indicate a cost of production of approximately €135 per ton of urea (internal rate of return more than 10 %) and savings of approximately 0.113 tons of CH4 and approximately 0.78 tons of CO2 per ton of urea produced. Thus, the results show that this waste-to-urea (WtU) technology is both economically valuable and environmentally advantageous (in terms of saving resources and limiting carbon footprint) for the production of chemicals from municipal solid waste in comparison with both the production of urea with conventional technology (starting from natural gas) and the use of RdF to produce electrical energy (waste-to-energy). A further benefit is the lower environmental impact of the solid residue produced from RdF conversion. The further benefit of this technology is the possibility to realize distributed fertilizer production.Waste not, want not: Waste valorization is an important component of a circular economy, but the current use of municipal solid waste is focused on energy production (waste-to-energy). We demonstrate here the economic and environmental advantages (resource preservation, lower carbon footprint, and toxicity impact) of a new waste-to-chemical technology for the production of urea, which is an important fertilizer and one of the top chemicals produced.
      PubDate: 2017-02-14T03:30:30.126933-05:
      DOI: 10.1002/cssc.201601555
       
  • A New Triazine-Based Covalent Organic Framework for High-Performance
           Capacitive Energy Storage
    • Authors: Piyali Bhanja; Kousik Bhunia, Sabuj K. Das, Debabrata Pradhan, Ryuto Kimura, Yuh Hijikata, Stephan Irle, Asim Bhaumik
      Pages: 921 - 929
      Abstract: The new covalent organic framework material TDFP-1 was prepared through a solvothermal Schiff base condensation reaction of the monomers 1,3,5-tris-(4-aminophenyl)triazine and 2,6-diformyl-4-methylphenol. Owing to its high specific surface area of 651 m2 g−1, extended π conjugation, and inherent microporosity, TDFP-1 exhibited an excellent energy-storage capacity with a maximum specific capacitance of 354 F g−1 at a scan rate of 2 mV s−1 and good cyclic stability with 95 % retention of its initial specific capacitance after 1000 cycles at 10 A g−1. The π-conjugated polymeric framework as well as ionic conductivity owing to the possibility of ion conduction inside the micropores of approximately 1.5 nm make polymeric TDFP-1 a favorable candidate as a supercapacitor electrode material. The electrochemical properties of this electrode material were measured through cyclic voltammetry, galvanic charge–discharge, and electrochemical impedance spectroscopy, and the results indicate its potential for application in energy-storage devices.Super framework: The new covalent organic framework TDFP-1 is prepared through a solvothermal Schiff base condensation reaction and shows an excellent energy-storage capacity with a maximum specific capacitance of 354 F g−1 at a scan rate of 2 mV s−1 and good cyclic stability (95 % retention of its initial specific capacitance after 1000 cycles).
      PubDate: 2017-02-20T08:55:34.447383-05:
      DOI: 10.1002/cssc.201601571
       
  • Crucial Role of Donor Density in the Performance of Oxynitride Perovskite
           LaTiO2N for Photocatalytic Water Oxidation
    • Authors: Feng-Qiang Xiong; Lipeng Wan, Yue Li, Tiju Thomas, Francis J. DiSalvo, Minghui Yang
      Pages: 930 - 937
      Abstract: LaTiO2N photocatalysts were prepared by thermal ammonolysis of flux-synthesized La2Ti2O7 and La2TiO5, and were investigated for water oxidation. Though LaTiO2N derived from La2TiO5 appears defect-free by UV/Vis/near-IR and electron paramagnetic resonance (EPR) spectroscopy, its performance is much lower than that of conventional La2Ti2O7-derived LaTiO2N with defects. It is shown by Mott–Schottky analysis that La2TiO5-derived LaTiO2N has significantly lower donor density; this can result in insufficient built-in electric field for the separation of photogenerated electrons and holes. The lower donor density is also consistent with the smaller difference between the Fermi level and the valence-band maximum, which accounts for a lower oxidative power of the holes. In light of this discovery, the donor density was increased substantially by introducing anion vacancies through annealing in Ar. This resulted in improved performance. The CoOx-assisted La2TiO5-derived LaTiO2N annealed at 713 °C has a higher quantum efficiency (25 %) at 450 nm than high-performance conventional CoOx/LaTiO2N (21 %).Improving photocatalysts: Sufficient donor density in LaTiO2N photocatalysts is essential to generate an efficient internal electric field for charge separation and for high oxidizing power of the holes. On the basis of this understanding, LaTiO2N photocatalysts were modified to give a quantum efficiency for water oxidation of 25 % at 450 nm, which is higher than that of conventional LaTiO2N.
      PubDate: 2017-02-17T07:15:32.47344-05:0
      DOI: 10.1002/cssc.201601602
       
  • High-Performance Porphyrin-Based Dye-Sensitized Solar Cells with Iodine
           and Cobalt Redox Shuttles
    • Authors: Huaide Xiang; Wei Fan, Jia Hui Li, Tianyue Li, Neil Robertson, Xiongrong Song, Wenjun Wu, Zhaohui Wang, Weihong Zhu, He Tian
      Pages: 938 - 945
      Abstract: Recently, enormous research passion has been devoted to enhance the power conversion efficiency (PCE) of porphyrin sensitizers for dye-sensitized solar cells (DSSCs), but the major stumbling block is the absorption defect in the visible-light region. To address this challenge, high-performance DSSCs are reported based on a new donor–π–acceptor sensitizer FW-1, 7H-dibenzo[c,g]carbazole-substituted and fused zinc porphyrin, co-sensitized with a benzotriazole-containing dye (WS-5) in iodine and cobalt redox systems, and high PCEs of 10.21 and 10.42 %, respectively, were obtained. An unprecedented breakthrough was obtained by making one sensitizer suitable for several electrolyte systems because of its appropriate molecular orbitals and co-sensitizer.Shuttle service: The improvement of the flexibility of the choice of electrolyte with a co-sensitizer is a significant issue for the development of dye-sensitized solar cells. Co-sensitization is used in this study to compensate the UV/Vis adsorption spectra and change the charge recombination inhibition significantly. High power conversion efficiencies of 10.21 and 10.42 %, respectively, are obtained for electrolytes based on iodine and cobalt redox shuttles.
      PubDate: 2017-02-21T08:11:38.924714-05:
      DOI: 10.1002/cssc.201601617
       
  • On the Structure–Property Relationships of Cation-Exchanged ZK-5
           Zeolites for CO2 Adsorption
    • Authors: Trong D. Pham; Matthew R. Hudson, Craig M. Brown, Raul F. Lobo
      Pages: 946 - 957
      Abstract: The CO2 adsorption properties of cation-exchanged Li-, Na-, K-, and Mg-ZK-5 zeolites were correlated to the molecular structures determined by Rietveld refinements of synchrotron powder X-ray diffraction patterns. Li-, K-, and Na-ZK-5 all exhibited high isosteric heats of adsorption (Qst) at low CO2 coverage, with Na-ZK-5 having the highest Qst (ca. 49 kJ mol−1). Mg2+ was located at the center of the zeolite hexagonal prism with the cation inaccessible to CO2, leading to a much lower Qst (ca. 30 kJ mol−1) and lower overall uptake capacity. Multiple CO2 adsorption sites were identified at a given CO2 loading amount for all four cation-exchanged ZK-5 adsorbents. Site A at the flat eight-membered ring windows and site B/B* in the γ-cages were the primary adsorption sites in Li- and Na-ZK-5 zeolites. Relatively strong dual-cation adsorption sites contributed significantly to an enhanced electrostatic interaction for CO2 in all ZK-5 samples. This interaction gives rise to a migration of Li+ and Mg2+ cations from their original locations at the center of the hexagonal prisms toward the α-cages, in which they interact more strongly with the adsorbed CO2.Identifying CO2 adsorption sites: A Rietveld refinement of a synchrotron powder X-ray diffraction pattern of CO2 dosed on Na-ZK-5 zeolite is used to determine the locations of adsorbed CO2 molecules. Three adsorption sites for CO2 are found: Site A is situated in the middle of the flat eight-membered ring windows, site B/B*, described as dual-cation adsorption sites to two Na+(II) cations, is the dominant site, and CO2 adsorption at site C can be considered as single or dual Na+ cation site in the α-cages.
      PubDate: 2017-02-16T06:10:34.642795-05:
      DOI: 10.1002/cssc.201601648
       
  • Study of Electrochemical Reduction of CO2 for Future Use in Secondary
           Microbial Electrochemical Technologies
    • Authors: Carla Gimkiewicz; Richard Hegner, Mareike F. Gutensohn, Christin Koch, Falk Harnisch
      Pages: 958 - 967
      Abstract: The fluctuation and decentralization of renewable energy have triggered the search for respective energy storage and utilization. At the same time, a sustainable bioeconomy calls for the exploitation of CO2 as feedstock. Secondary microbial electrochemical technologies (METs) allow both challenges to be tackled because the electrochemical reduction of CO2 can be coupled with microbial synthesis. Because this combination creates special challenges, the electrochemical reduction of CO2 was investigated under conditions allowing microbial conversions, that is, for their future use in secondary METs. A reproducible electrodeposition procedure of In on a graphite backbone allowed a systematic study of formate production from CO2 with a high number of replicates. Coulomb efficiencies and formate production rates of up to 64.6±6.8 % and 0.013±0.002 mmolformate h−1 cm−2, respectively, were achieved. Electrode redeposition, reusability, and long-term performance were investigated. Furthermore, the effect of components used in microbial media, that is, yeast extract, trace elements, and phosphate salts, on the electrode performance was addressed. The results demonstrate that the integration of electrochemical reduction of CO2 in secondary METs can become technologically relevant.Energy storage with CO2: The electrochemical reduction of CO2 was investigated under conditions allowing microbial conversions for future use in secondary microbial electrochemical technologies (METs). A reproducible electrodeposition procedure of In on a graphite backbone allowed a systematic study of formate production from CO2 with coulombic efficiencies of 64.6±6.8 % and formate production rates of 0.013±0.002 mmolformate h−1 cm−2. The results demonstrate that the integration of electrochemical reduction of CO2 in secondary METs can become technologically relevant.
      PubDate: 2017-02-20T02:55:28.313451-05:
      DOI: 10.1002/cssc.201601675
       
  • Tetraphenylmethane-Arylamine Hole-Transporting Materials for Perovskite
           Solar Cells
    • Authors: Xuepeng Liu; Fantai Kong, Tai Cheng, Wangchao Chen, Zhan'ao Tan, Ting Yu, Fuling Guo, Jian Chen, Jianxi Yao, Songyuan Dai
      Pages: 968 - 975
      Abstract: A new class of hole-transporting materials (HTM) containing tetraphenylmethane (TPM) core have been developed. After thermal, charge carrier mobility, and contact angle tests, it was found that TPA-TPM (TPA: arylamine derivates side group) showed higher glass-transition temperature and larger water-contact angle than spiro-OMeTAD with comparable hole mobility. Photoluminescence and impedance spectroscopy studies indicate that TPA-TPM's hole-extraction ability is comparable to that of spiro-OMeTAD. SEM and AFM results suggest that TPA-TPM has a smooth surface. When TPA-TPM is used in mesoscopic perovskite solar cells, power conversion efficiency comparable to that of spiro-OMeTAD is achieved. Notably, the perovskite solar cells employing TPA-TPM show better long-term stability than that of spiro-OMeTAD. Moreover, TPA-TPM can be prepared from relatively inexpensive raw materials with a facile synthetic route. The results demonstrate that TPM-arylamines are a new class of HTMs for efficient and stable perovskite solar cells.“Hole”efficiency: New hole-transporting materials for perovskite solar cells are developed using tetraphenylmethane (TPM) as core and arylamine side groups (TPA and DPA). TPA-TPM can achieve power conversion efficiency comparable to spiro-OMeTAD as well as improved long-term stability.
      PubDate: 2017-02-10T03:30:28.452049-05:
      DOI: 10.1002/cssc.201601683
       
  • One-Pot Anchoring of Pd Nanoparticles on Nitrogen-Doped Carbon through
           Dopamine Self-Polymerization and Activity in the Electrocatalytic Methanol
           Oxidation Reaction
    • Authors: Xin Li; Xiangheng Niu, Wenchi Zhang, Yanfang He, Jianming Pan, Yongsheng Yan, Fengxian Qiu
      Pages: 976 - 983
      Abstract: Exploration of advanced electrocatalysts to promote the sluggish methanol oxidation reaction (MOR) is of vital importance for developing high efficiency and low-cost direct methanol fuel cells. Highly dispersed palladium nanoparticles (Pd NPs) anchored on a nitrogen-doped carbon support were fabricated using a facile one-pot dopamine self-polymerization mediated redox strategy, in which dopamine not only acted as a moderate reductant to induce the formation of Pd NPs during self-polymerization but was also the precursor of the nitrogen-doped carbon support for Pd. The synthesized hybrid features the following characteristics: 1) High dispersity of Pd NPs, which exposed a high abundance of active surfaces and sites for heterogeneous electrocatalysis; 2) metal-support interactions, which may affect the surface chemistry and electron distribution of active Pd NPs; 3) the Pd NPs were partially imbedded or encapsulated into the support, thus reducing the possible agglomeration of Pd NPs during cyclic measurements. The electrocatalyst with such favorable features provided higher mass activity (2.2 times that of commercial Pd/C) and better durability (reduced loss of activity during simulated frequent startup–shutdown operations) for the MOR in alkaline media.One pot for MORe: A one-pot dopamine self-polymerization mediated redox strategy is used to fabricate highly dispersed Pd nanoparticles anchored on a nitrogen-doped carbon support. The material is used to catalyze the methanol oxidation reaction (MOR) with higher mass activity and durability than commercial Pd/C.
      PubDate: 2017-02-21T08:11:51.419976-05:
      DOI: 10.1002/cssc.201601732
       
  • Lignin-Based Materials Through Thiol–Maleimide “Click”
           Polymerization
    • Authors: Pietro Buono; Antoine Duval, Luc Averous, Youssef Habibi
      Pages: 984 - 992
      Abstract: In the present report an environmentally friendly approach to transforming renewable feedstocks into value-added materials is proposed. This transformation pathway was conducted under green conditions, without the use of solvents or catalyst. First, controlled modification of lignin, a major biopolymer present in wood and plants, was achieved by esterification with 11-maleimidoundecylenic acid (11-MUA), a derivative from castor oil that contains maleimide groups, following its transformation into 11-maleimidoundecanoyl chloride (11-MUC). Different degrees of substitution were achieved by using various amounts of the 11-MUC, leading to an efficient conversion of lignin hydroxy groups, as demonstrated by 1H and 31P NMR analyses. These fully biobased maleimide-lignin derivatives were subjected to an extremely fast (ca. 1 min) thiol–ene “click” polymerization with thiol-containing linkers. Aliphatic and aromatic thiol linkers bearing two to four thiol groups were used to tune the reactivity and crosslink density. The properties of the resulting materials were evaluated by swelling tests and thermal and mechanical analyses, which showed that varying the degree of functionality of the linker and the linker structure allowed accurate tailoring of the thermal and mechanical properties of the final materials, thus providing interesting perspectives for lignin in functional aromatic polymers.“Clicknin” materials: Soda lignin is functionalized with 11-maleimidoundecylenic acid (11-MUA) under solvent- and catalyst-free conditions and further polymerized through a thiol–ene “click” reaction with different polyfunctional thiol linkers. The resultant materials have a final lignin content of 30–40 % and tailored thermomechanical properties depending on the degree of functionality of the linker and the 11-MUA content.
      PubDate: 2017-02-21T08:06:48.107298-05:
      DOI: 10.1002/cssc.201601738
       
  • Highly Stable Sr-Free Cobaltite-Based Perovskite Cathodes Directly
           Assembled on a Barrier-Layer-Free Y2O3-ZrO2 Electrolyte of Solid Oxide
           Fuel Cells
    • Authors: Na Ai; Na Li, William D. A. Rickard, Yi Cheng, Kongfa Chen, San Ping Jiang
      Pages: 993 - 1003
      Abstract: Direct assembly is a newly developed technique in which a cobaltite-based perovskite (CBP) cathode can be directly applied to a barrier-layer-free Y2O3-ZrO2 (YSZ) electrolyte with no high-temperature pre-sintering steps. Solid oxide fuel cells (SOFCs) based on directly assembled CBPs such as La0.6Sr0.4Co0.2Fe0.8O3−δ show high performance initially but degrade rapidly under SOFC operation conditions at 750 °C owing to Sr segregation and accumulation at the electrode/electrolyte interface. Herein, the performance and interface of Sr-free CBPs such as LaCoO3−δ (LC) and Sm0.95CoO3−δ (SmC) and their composite cathodes directly assembled on YSZ electrolyte was studied systematically. The LC electrode underwent performance degradation, most likely owing to cation demixing and accumulation of La on the YSZ electrolyte under polarization at 500 mA cm−2 and 750 °C. However, the performance and stability of LC electrodes could be substantially enhanced by the formation of LC-gadolinium-doped ceria (GDC) composite cathodes. Replacement of La by Sm increased the cell stability, and doping of 5 % Pd to form Sm0.95Co0.95Pd0.05O3−δ (SmCPd) significantly improved the electrode activity. An anode-supported YSZ-electrolyte cell with a directly assembled SmCPd-GDC composite electrode exhibited a peak power density of 1.4 W cm−2 at 750 °C, and an excellent stability at 750 °C for over 240 h. The higher stability of SmC as compared to that of LC is most likely a result of the lower reactivity of SmC with YSZ. This study demonstrates the new opportunities in the design and development of intermediate-temperature SOFCs based on the directly assembled high-performance and durable Sr-free CBP cathodes.Electrochemistry: The performance stability of directly assembled La cobaltites can be significantly enhanced by forming a composite electrode or by replacing La with Sm. This study demonstrates the new opportunities in the design and development of intermediate-temperature solid oxide fuel cells based on the directly assembled high-performance and durable Sr-free cobaltite-based perovskite cathodes.
      PubDate: 2017-02-21T08:12:02.808512-05:
      DOI: 10.1002/cssc.201601645
       
  • Carbon-Nanodot Solar Cells from Renewable Precursors
    • Authors: Adam Marinovic; Lim S. Kiat, Steve Dunn, Maria-Magdalena Titirici, Joe Briscoe
      Pages: 1004 - 1013
      Abstract: It has recently been shown that waste biomass can be converted into a wide range of functional materials, including those with desirable optical and electronic properties, offering the opportunity to find new uses for these renewable resources. Photovoltaics is one area in which finding the combination of abundant, low-cost and non-toxic materials with the necessary functionality can be challenging. In this paper the performance of carbon nanodots derived from a wide range of biomaterials obtained from different biomass sources as sensitisers for TiO2-based nanostructured solar cells was compared; polysaccharides (chitosan and chitin), monosaccharide (d-glucose), amino acids (l-arginine and l-cysteine) and raw lobster shells were used to produce carbon nanodots through hydrothermal carbonisation. The highest solar power conversion efficiency (PCE) of 0.36 % was obtained by using l-arginine carbon nanodots as sensitisers, whereas lobster shells, as a model source of chitin from actual food waste, showed a PCE of 0.22 %. By comparing this wide range of materials, the performance of the solar cells was correlated with the materials characteristics by carefully investigating the structural and optical properties of each family of carbon nanodots, and it was shown that the combination of amine and carboxylic acid functionalisation is particularly beneficial for the solar-cell performance.Biomaterials-to-nanomaterials for solar energy: Carbon nanodots synthesised by hydrothermal method from a wide range of biomaterials are used as sensitisers for TiO2-based nanostructured solar cells, and their performance is analysed and compared. l-arginine carbon nanodots used as sensitisers show the highest solar power conversion efficiency (PCE) of 0.36 %, whereas carbon nanodots from lobster shells show a PCE of 0.22 %.
      PubDate: 2017-02-14T03:25:35.09654-05:0
      DOI: 10.1002/cssc.201601741
       
  • Synthesis of Cobalt Phosphide Nanoparticles Supported on Pristine Graphene
           by Dynamically Self-Assembled Graphene Quantum Dots for Hydrogen Evolution
           
    • Authors: Xiaoyan Wang; Weiyong Yuan, Yanan Yu, Chang Ming Li
      Pages: 1014 - 1021
      Abstract: A highly active, durable, and low-cost hydrogen evolution reaction (HER) catalyst is desirable for energy storage through water splitting but its fabrication presents great challenges. Herein, mediated by dynamically self-assembled graphene quantum dots (GQDs), small, uniform, high-density, and well-dispersed CoP nanoparticles were grown in situ on pristine graphene for the first time. This hybrid nanostructure was then employed as HER electrocatalyst, showing an onset potential of 7 mV, an overpotential of 91.3 mV to achieve 10 mA cm−2, a Tafel slope of 42.6 mV dec−1, and an exchange current density of 0.1225 mA cm−2, all of which compare favorably to those of most reported non-noble-metal catalysts. The developed catalyst also exhibits excellent durability with negligible current loss after 2000 cyclic voltammetry cycles (+0.01 to −0.17 V vs. RHE) or 34 h of chronoamperometric measurement at an overpotential of 91.3 mV. This work not only develops a new strategy for the fabrication of high-performance and inexpensive electrocatalysts for HER but also provides scientific insight into the mechanism of the dynamically self-assembled GQDsmediated synthesis process.CoProducing H2: Small, uniform, high-density, and well-dispersed CoP nanoparticles (NPs) were grown in situ on pristine graphene for the first time by dynamically self-assembled graphene quantum dots (GQDs)-mediated synthesis, showing a very high catalytic activity and excellent durability toward the hydrogen evolution reaction.
      PubDate: 2017-01-31T04:10:46.364308-05:
      DOI: 10.1002/cssc.201601761
       
  • Lignin Depolymerisation and Lignocellulose Fractionation by Solvated
           Electrons in Liquid Ammonia
    • Authors: Pepijn Prinsen; Anand Narani, Gadi Rothenberg
      Pages: 1022 - 1032
      Abstract: We explored the depolymerisation of several lignins in liquid ammonia at relatively high temperatures and pressures (120 °C and 88 bar). Five different lignins were tested: Indulin AT kraft, Protobind 1000 soda, wheat straw organosolv, poplar organosolv and elephant grass-milled wood lignin (EG MWL). In pure liquid ammonia, all lignins underwent slow incorporation of nitrogen into their structure, resulting in higher molecular weight and polydispersity index. Subsequently, we show a reductive depolymerisation by solvated electrons at room temperature by adding sodium metal to the liquid ammonia without any external hydrogen donor. The netto yields of bio-oil are low for technical lignins (10–23 %), but with higher yields of alkylphenols. In the case of native EG MWL, netto yields of 40 % bio-oil were achieved. Finally, when the room temperature method was applied to poplar wood fibre, we observe improved delignification upon the addition of sodium compared to poplar wood fractionation in pure liquid ammonia.Dissolve and mix: Lignin, the gluey stuff that holds trees together, is easily dissolved in anhydrous liquid ammonia. Combining this with metallic sodium, various native and technical lignins can be depolymerized, giving bio-oils.
      PubDate: 2017-01-31T04:17:04.979329-05:
      DOI: 10.1002/cssc.201601608
       
  • Back Cover: Direct Synthesis of Renewable Dodecanol and Dodecane with
           Methyl Isobutyl Ketone over Dual-Bed Catalyst Systems (ChemSusChem 5/2017)
           
    • Authors: Xueru Sheng; Ning Li, Guangyi Li, Wentao Wang, Aiqin Wang, Yu Cong, Xiaodong Wang, Tao Zhang
      Pages: 1033 - 1033
      Abstract: The Back Cover picture shows a rooster and a hen in commemoration of 2017 being the Chinese rooster year. Both are labeled as MIBK (methyl isobutyl ketone). The rooster is eating the grass, which represents biomass and lignocellulose. Their products: two chickens; one represents SDS (sodium dodecylsulfate) and the other represents jet fuel. These are the two products that can be produced from our method using duel-bed catalysis systems. More details can be found in the Communication by Sheng et al. on page 825 in Issue 5, 2017 (
      DOI : 10.1002/cssc.201601563).
      PubDate: 2017-03-07T05:30:43.35597-05:0
       
  • Selective Hydrogenolysis of Glycerol to 1,3-Propanediol: Manipulating the
           Frustrated Lewis Pairs by Introducing Gold to Pt/WOx
    • Authors: Xiaochen Zhao; Jia Wang, Man Yang, Nian Lei, Lin Li, Baolin Hou, Shu Miao, Xiaoli Pan, Aiqin Wang, Tao Zhang
      Pages: 819 - 824
      Abstract: A highly dispersed Au and Pt catalyst supported on WOx was developed for high performance in the selective hydrogenolysis of glycerol to 1,3-propanediol (1,3-PD) under very mild reaction conditions (81.4 % glycerol conversion, 51.6 % 1,3-PD selectivity at 413 K, 1 MPa H2). The highly dispersed Au decreased the original surface Lewis-acid sites on Pt/WOx but greatly increased its in situ generated Brønsted-acid sites with the assistance of H2 through the formation of frustrated Lewis pairs. These in situ formed and spatially separated pairs of H+ and H− function as the active sites in glycerol conversion to 1,3-PD.A golden opportunity: Pt/WOx catalysts are significantly promoted by the addition of highly dispersed Au through manipulation of the frustrated Lewis-acid-pair sites. The resulting AuPt/WOx catalysts are highly active and selective for hydrogenolysis of glycerol to 1,3-propanediol under mild conditions.
      PubDate: 2016-12-28T07:25:39.822954-05:
      DOI: 10.1002/cssc.201601503
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.158.109.89
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016