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  Subjects -> MATHEMATICS (Total: 874 journals)
    - APPLIED MATHEMATICS (71 journals)
    - GEOMETRY AND TOPOLOGY (19 journals)
    - MATHEMATICS (647 journals)
    - MATHEMATICS (GENERAL) (41 journals)
    - NUMERICAL ANALYSIS (19 journals)
    - PROBABILITIES AND MATH STATISTICS (77 journals)

MATHEMATICS (647 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: 7)
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: 21)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 11)
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: 6)
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: 10)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 1)
Advances in Materials Sciences     Open Access   (Followers: 16)
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: 4)
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: 3)
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   (Followers: 1)
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 Network Science     Open Access  
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: 18)
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: 7)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 2)
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: 21)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 7)
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: 1)
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: 17)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (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: 2)
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: 14)
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: 12)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 29)
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: 5)
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)
Foundations and Trends® in Econometrics     Full-text available via subscription   (Followers: 4)

        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  [1583 journals]
  • Low-cost Carbazole-based Hole Transport Material for Highly Efficient
           Perovskite Solar Cells
    • Authors: Zhiliang Chen; Hui Li, Xiaolu Zheng, Qi Zhang, Zhanfeng Li, Yuying Hao, Guojia Fang
      Abstract: A low cost carbazole based small molecule material 1,3,6,8-tetra(N,N-p-dimethoxyphenylamino)-9-ethyl-carbazole was designed and synthesized using a facile three-step synthetic route. The novel material was fully characterized and further applied as hole transport material (HTM) for low temperature processed planar perovskite solar cells (PSCs). Devices based on this new HTM exhibit a high power conversion efficiency (PCE) of 17.8%, which is comparable to that (PCE of 18.6%) of the costly 2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) based PSCs.
      PubDate: 2017-06-26T22:17:38.710381-05:
      DOI: 10.1002/cssc.201700678
       
  • Sustainable Biomass-Derived Catalysts for Selective Hydrogenation of
           Nitroarenes
    • Authors: Basudev Sahoo; Dario Formenti, Christoph Topf, Stephan Bachmann, Michelangelo Scalone, Kathrin Junge, Matthias Beller
      Abstract: Development of catalytically active materials from biowaste represents an important aspect of sustainable chemical research. Three heterogeneous materials were synthesized from inexpensive biomass based chitosan and abundant Co(OAc)₂via complexation followed by pyrolysis at various temperatures. These materials were applied for the catalytic hydrogenation of nitroarenes using molecular hydrogen. A variety of diversely functionalized nitroarenes including few pharmaceutically active compounds were selectively converted to aromatic amines in high yield and selectivity with excellent functional group tolerance. As an example, this green protocol has also been implemented for the synthesis of biologically important TRPC3 inhibitor.
      PubDate: 2017-06-26T09:17:52.80268-05:0
      DOI: 10.1002/cssc.201700796
       
  • Anionic extraction for efficient recovery of bio-based 2,3-butanediol - a
           platform for bulk and fine chemicals
    • Authors: Peter Drabo; Till Tiso, Benedikt Heyman, Eda Sarikaya, Paula Gaspar, Jochen Förster, Jochen Büchs, Lars Mathias Blank, Irina Delidovich
      Abstract: 2,3-Butanediol (BDO) presents a promising platform molecule for the synthesis of basic and fine chemicals. Biotechnological production of BDO from renewable resources with living microbes enables high concentrations in the fermentation broth. The recovery of the high-boiling BDO from an aqueous fermentation broth presents the subsequent challenge. Here we propose a method for BDO isolation based on a reversible complexation with phenylboronate into an anionic complex. BDO can be recovered by back-extraction into an acidic solution. The composition of the extracted species was determined by NMR, MS, and GC-MS methods. The conditions of extraction and back-extraction were optimized using commercial BDO and finally applied to different fermentation broths. Up to 72-93% BDO can be extracted and up to 80-90% can be back-extracted under the optimized conditions. Purified bio-BDO was used in the presence of sulphuric acid for synthesis of methyl ethyl ketone (MEK), an established organic solvent and discussed tailor-made biofuel.
      PubDate: 2017-06-26T05:17:38.079088-05:
      DOI: 10.1002/cssc.201700899
       
  • Low-cost Perovskite Solar Cells Employing
           Dimethoxydiphenylamine-Substituted Bistricyclic Aromatic Enes as Hole
           Transporting Materials
    • Authors: Mohammad Khaja Nazeeruddin; Kasparas Rakstys, Sanghyun Paek, Giulia Grancini, Peng Gao, Vygintas Jankauskas, Abdullah M. Asiri
      Abstract: The synthesis, characterization and photovoltaic performance of series of novel molecular hole transporting materials (HTMs) based on bistricyclic aromatic enes (BAEs) are presented. The new derivatives have been obtained following the simple and straightforward two-step procedure from inexpensive starting reagents mimicking the synthetically challenging 9,9'-spirobifluorene moiety of the well-studied spiro-OMeTAD. The novel HTMs are tested in mixed caions and anions perovskite solar cells (PSCs) yielding power conversion efficiency (PCE) of 19.2% under standard global 100 mW cm−2 AM 1.5G illumination using 9-(2,7-bis(bis(4-methoxyphenyl)amino)-9H-fluoren-9-ylidene)-N2,N2,N7,N7-tetrakis(4-methoxyphenyl)-9H-thioxanthene-2,7-diamine (coded as KR374). The power conversion efficiency data confirms the easily attainable heteromerous fluorenylidenethioxanthene structure as valuable core for low-cost and highly efficient HTM design and paves the way towards cost-effective PSC technology.
      PubDate: 2017-06-26T04:17:33.543787-05:
      DOI: 10.1002/cssc.201700974
       
  • Mechanism of Microwave-assisted Pyrolysis of Glucose to Furfural Revealed
           by Isotopic Tracer and Quantum Chemical Calculations
    • Authors: Liwei Bao; Lei Shi, Hu Luo, Lingzhao Kong, Shenggang Li, Wei Wei, Yuhan Sun
      Abstract: Glucose labelled with 13C or 18O was used to investigate the mechanism during its conversion into furfural by microwave-assisted pyrolysis. The isotopic content and location in furfural were determined from GC/MS and 13C NMR measurements and data analysis. Our results suggest that the carbon skeleton in furfural is mainly derived from the C-1 to C-5 of glucose. The C of the aldehyde group and the O of the furan ring in furfural are primarily originated from the C-1 and O-5 of glucose, respectively. For the first time, the source of the O of the furan ring in furfural was elucidated directly by experiments, which is consistent with predictions from recent quantum chemical calculations. Furthermore, our own theoretical calculations yield substantially lower energy barriers than the previous predictions by considering the potential catalytic effect of formic acid, which is one of the pyrolysis products. The catalytic role of formic acid is further confirmed by our experimental evidence.
      PubDate: 2017-06-25T22:17:36.59933-05:0
      DOI: 10.1002/cssc.201700621
       
  • Enhancing perovskite electrocatalysis of solid oxide cells through
           controlled growth of nanoparticles
    • Authors: Bin Hua; Meng Li, Yi-Fei Sun, Jian-Hui Li, Jing-Li Luo
      Abstract: Perovskite oxides have received a great deal of attentions as promising electrodes in both solid oxide fuel cells (SOFCs) and solid oxide electrolyzer cells (SOECs) because of their reasonable reactivity, impurity tolerance, tunable property, etc. Particular explorations are still required for advancing the perovskite electrodes, which normally suffer from slow kinetics in electrocatalysis. In the past decades, several experimental studies have developed new classes of perovskites with advanced characteristics and electrode kinetics at technical levels. In parallel with those developments, the achievements in theoretical and computational studies have led to substantial understanding, at the atomic level, of their physicochemical properties and electrocatalytic behaviors. The chemical and structural flexibilities enable the perovskites to accommodate most metallic elements without destroying their complex matrix structures, thereby delivering a pathway to engineering their catalytic properties. In this contribution, we briefly introduce the recent advances in perovskite electrodes, and focus on the perovskites with exsolved nanoparticles as the enhanced electrocatalytic materials.
      PubDate: 2017-06-24T01:47:27.982784-05:
      DOI: 10.1002/cssc.201700936
       
  • Evaluating Dihydroazulene-Vinylheptafulvene Photoswitches for Solar Energy
           Storage Applications
    • Authors: Zhihang Wang; Jonas Udmark, Karl Börjesson, Rita Rodrigues, Anna Roffey, Maria Abrahamsson, Mogens B Nielsen, Kasper Moth-Poulsen
      Abstract: Efficient solar energy storage is a key challenge in striving towards a sustainable future. For this reason, molecules capable of solar energy storage and release through valence isomerization, so-called Molecular Solar Thermal energy storage (MOST), have been investigated. Here, we evaluate the energy storage potential through the photoconversion of the dihydroazulene-vinylheptafulvene (DHA/VHF) photo-thermal couple. The robust nature of this system has been determined through multiple energy storage and release cycles at elevated temperatures in three different solvents. In a non-polar solvent such as toluene, the DHA/VHF system can be cycled more than 70 times with less than 0.01% degradation per cycle. Moreover, the [Cu(CH3CN)4]PF6 catalyzed conversion of VHF to DHA was demonstrated in a flow reactor. The performance of the DHA/VHF couple was also evaluated in prototype photoconversion devices, both in the laboratory using a flow chip under simulated sunlight, and under outdoor conditions by using a parabolic mirror. Device experiments demonstrated a solar energy storage efficiency up to 0.13% in the chip device and up to 0.02% in the parabolic collector, respectively. Avenues for future improvements and optimization of the system are discussed herein.
      PubDate: 2017-06-23T10:45:24.556749-05:
      DOI: 10.1002/cssc.201700679
       
  • Quantitative insights into the Fast Pyrolysis of Extracted Cellulose,
           Hemicelluloses and Lignin
    • Authors: Marion Carrier; Michael Windt, Bernhard Ziegler, Jörn Appelt, Bodo Saake, Dietrich Meier, Anthony Bridgwater
      Abstract: The transformation of lignocellulosic biomass into bio-based commodity chemicals is technically possible. Among thermochemical processes, fast pyrolysis, a relatively mature technology that has now reached the commercial level, produces a high yield of an organic-rich liquid stream. Despite the recent efforts in elucidating the degradation paths of biomass pyrolysis, the selectivity and recovery rates of bio-compounds remain low. In an attempt to clarify the general degradation scheme of biomass fast pyrolysis and provide a quantitative insight, this study has combined the use of fast pyrolysis micro-reactors, spectrometric techniques and mixtures of unlabelled and Carbon-13 enriched materials. The first stage of the work reported aimed at selecting the type of reactor to ensure control of the pyrolysis regime. The comparison of chemical fragmentation patterns of 'primary' fast pyrolysis volatiles detectable by GC-MS between two small scale micro-reactors has shown the inevitable presence of secondary reactions. In a second stage, liquid fractions also made of 'primary' fast pyrolysis condensables have been analysed by quantitative liquid-state 13C-NMR providing a quantitative distribution of functional groups. The compilation of those results into a map that displays the distribution of functional groups according to the individual and main constituents of biomass confirmed the origin of individual chemicals within fast pyrolysis liquids.
      PubDate: 2017-06-23T07:51:02.255897-05:
      DOI: 10.1002/cssc.201700984
       
  • Hydroxyacetone: A glycerol based platform for electrocatalytic
           hydrogenation and hydrodeoxygenation processes
    • Authors: Waldemar Sauter; Olaf Lennart Bergmann, Uwe Schröder
      Abstract: Here we propose the use of hydroxyacetone, a dehydration product of glycerol, as a platform for the electrocatalytic synthesis of acetone, 1,2-propanediol and 2-propanol. 11 non-noble metals were investigated as electrode materials in combination with three different electrolyte compositions towards the selectivity, Coulomb efficiency (CE) and reaction rates of the electrocatalytic hydrogenation (formation of 1,2-propanediol) and hydrodeoxygenation (formation of acetone and propanol) of hydroxyacetone. With a selectivity of 84.5%, a reaction rate of 782 mmol/h*m2 and a CE of 32% (for 0.09 M hydroxyacetone), iron electrodes, in a chloride electrolyte, yielded the best 1,2 propanediol formation. A further enhancement of the performance can be achieved upon increasing the educt concentration to 0.5 M, yielding a reaction rate of 2248.1 mmol/ h*m² and a CE of 64.5%. Acetone formation was optimal at copper and lead electrodes in chloride solution, with lead showing the lowest tendency of side product formation. 2-propanol formation can be achieved using a consecutive oxidation of the formed acetone (at iron electrodes). 1-propanol formation was observed only in traces.
      PubDate: 2017-06-23T05:50:37.411707-05:
      DOI: 10.1002/cssc.201700996
       
  • Comprehensive insights into the thermal stability, biodegradability and
           combustion chemistry of Pyrrolidinium-based Ionic Liquids
    • Authors: Gebrekidan Gebreselassie Eshetu; Sangsik Jeong, Pascal Pandard, Amandine Lecocq, Guy Marlair, Stefano Passerini
      Abstract: The use of ionic liquids (ILs) as advanced electrolytes components in electrochemical energy storage devices is one of the most appealing and emerging options. However, though ILs are hailed as safer and eco-friendly electrolytes, overcoming the limitations imposed by the highly volatile/combustible carbonate based electrolytes, the full scale and precise appraisal of their overall safety levels under abuse conditions still need to be fully addressed. With the aim of providing the entreated level of information on the thermal and chemical stabilities as well as actual fire hazards, we embarked on a detailed investigation of the short - and long - term thermal stabilities, bio-degradability and combustion behaviour of various pyrrolidinium ([Pyr1A] +)-based ILs, enlisting different alkyl chain lengths, [Pyr1A] + (A=3-10), counter-anions ([TFSI]-/[FSI]-/[BETI]-), cations (Pyr14+/Pyr12O1+) and the effect of doping with Li salts (e.g. Li[TFSI]/[Pyr14] [TFSI]).
      PubDate: 2017-06-23T05:50:33.235195-05:
      DOI: 10.1002/cssc.201701006
       
  • Design of Iron(II) Pthalocyanine (FePc) Derived Oxygen Reduction
           Electrocatalysts for High Power Density Microbial Fuel Cells
    • Authors: Carlo Santoro; Rohan Gokhale, Barbara Mecheri, Alessandra D'Epifanio, Silvia Licoccia, Alexey Serov, Kateryna Artyushkova, Plamen Atanassov
      Abstract: Iron(II) Phthalocyanine (FePc) deposited onto two different carbonaceous supports was synthesized by the non-conventional pyrolysis-free method, studied in the reaction of oxygen reduction (ORR) in neutral media, incorporated in an air-breathing cathode structure and tested in operating microbial fuel cell (MFC) configuration. Rotating ring disk electrode (RRDE) analysis revealed high performances of the Fe-based catalysts compared with activated carbon (AC). It was shown that Black Pearls supported FePc (Fe-BP(N)) exhibits the highest performance in term of more positive onset, positive shift of half-wave potential and higher limiting as well as highest power density in operating MFC (243±7 μWcm-2) that was 33% higher than Fe-CNT(N) (182±5 μWcm-2). Power density generated by Fe-BP(N) was 92% higher than AC indicating that the utilization of PGM-free catalysts can boost up significantly the performances of MFCs.
      PubDate: 2017-06-23T04:05:35.994542-05:
      DOI: 10.1002/cssc.201700851
       
  • Molecular Self-Assembly Fabrication and Carrier Dynamics of Stable and
           Efficient CH3NH3Pb(1−x)SnxI3 Perovskite Solar Cells
    • Authors: Jiandong Fan; Chong Liu, Hongliang Li, Cuilin Zhang, Wenze Li, Yaohua Mai
      Abstract: The Sn-based perovskite solar cells (PSCs) provide the possibility that swaps the Pb element toward toxic-free PSCs. Here, we innovatively employed a molecular self-assembly approach to obtain a series CH3NH3Pb(1−x)SnxI3 (0≤x≤1) perovskite thin films with full coverage. The optimized planar CH3NH3Pb0.75Sn0.25I3 PSCs with inverted structure was consequently realized with a maximum power conversion efficiency (PCE) over 14 %, which displayed a stabilized power output (SPO) over 12 % within 200 s at 0.6 V forward bias. Afterward, we investigated the factors that limited the efficiency improvement of hybrid Sn-Pb PSCs, and analyzed the possible reason of the hysteresis effect occurred even in the inverted structure cell. Particularly, the oxidation of hybrid Sn-Pb perovskite thin film was demonstrated to be the main reason that caused the decreasing of minority-carrier lifetime, which quenched the carrier collection efficiency while the depletion layer was widened. The imbalance of charge transport was intensified that was associated with the increased hole defect-state density and decreased the electron defect-state density after Sn was introduced. This study is benefit to tackle the intractable issue regarding the toxic Pb in perovskite devices and step forward toward realizing the lead-free PSCs with high stability and efficiency.
      PubDate: 2017-06-22T20:51:01.167451-05:
      DOI: 10.1002/cssc.201700880
       
  • Nanoelectrical and Nanoelectrochemical Imaging of Pt/p-Si and Pt/p+-Si
           Electrodes
    • Authors: Jingjing Jiang; Zhuangqun Huang, Chengxiang Xiang, Rakesh Poddar, Hans-Joachim Lewerenz, Kimberly M. Papadantonakis, Nathan Lewis, Bruce Brunschwig
      Abstract: The interfacial properties of electrolessly deposited Pt nanoparticles (Pt-NP) on p-Si and p+-Si electrodes have been resolved on the nanometer scale using a combination of scanning probe methods. Atomic-force microscopy (AFM) showed highly dispersed Pt nanoparticles. Conductive AFM measurements showed that only about half of the particles exhibited measurable contact currents, with a factor of 10^3 difference in current. Local current-voltage measurements revealed a rectifying junction with a resistance of ≥ 10 MΩ at the Pt-NP/p-Si interface, while Pt-NP/p+-Si samples formed an Ohmic junction with a local resistance of ≥ 1 MΩ. The particles were strongly attached to the sample surface in air. However in contact with an electrolyte, the adhesion of the particles to the surface was substantially lower. Scanning electrochemical microscopy (SECM) showed smaller, but more uniform electrochemical currents for the particles relative to the currents observed in conductive AFM measurements. In accord with the conductive AFM measurements, SECM measurements showed conductance through the substrate for only a minority of the particles. These results suggest that the electrochemical performance of the electrolessly deposited Pt nanoparticles on Si is ascribable to: 1) the high resistance of the contact between the particles and the substrate; 2) the low (
      PubDate: 2017-06-21T12:45:47.696481-05:
      DOI: 10.1002/cssc.201700893
       
  • A Perylene-Based Polycyclic Aromatic Hydrocarbon Electron-Donor for a
           Highly Efficient Solar Cell Dye
    • Authors: Junting Wang; Heng Wu, Linrui Jin, Jing Zhang, Yi Yuan, Peng Wang
      Abstract: The continuing efforts of creating novel polycyclic aromatic hydrocarbons (PAHs) and exploiting them as the crucial building-blocks of organic donor-acceptor (D-A) dyes with excellent excited state features, should bring an unprecedented chance for the improvement of power conversion efficiency (PCE) of dye-sensitized solar cells (DSCs). In this paper we report a nonacyclic aromatic hydrocarbon, N-annulated benzoindenopentaphene (NBIP), which can be tethered with multiple solubilizing groups including one 2-hexyldecyl, one 2-hexyldecyloxy, and four 4-hexylphenyl substituents. The side- and end-chain functionalized NBIP can be conveniently prepared at an excellent yield, and further cross-coupled with 4-(7-ethynylbenzo[c][1,2,5]thiadiazol-4-yl)benzoic acid to afford a metal-free D-A dye C293, achieving a high power conversion efficiency of 12.6% under the AM1.5G condition, in DSCs without use of any coadsorbent.
      PubDate: 2017-06-20T00:41:09.370426-05:
      DOI: 10.1002/cssc.201700916
       
  • Quantitative NMR Approach to Optimize the Formation of Chemical Building
           Blocks from Abundant Carbohydrates
    • Authors: Sebastian Meier; Samuel Elliot, Søren Tolborg, Irantzu Sadaba Zubiri, Esben Taarning
      Abstract: The future role of biomass-derived chemicals relies on the formation of diverse functional monomers in high yields from carbohydrates. Recently, it has become clear that a series of α-hydroxy acids, esters and lactones can be formed from carbohydrates in alcohols and water using tin-containing catalysts such as Sn-Beta. These compounds are potential building blocks for polyesters with additional olefin and alcohol functionalities. We employ an NMR approach to identify, quantify and optimize the formation these building blocks in the chemocatalytic transformation of abundant carbohydrates by Sn-Beta. Record yields of the target molecules can be achieved by obstructing competing reactions through solvent choice.
      PubDate: 2017-06-19T06:20:45.170886-05:
      DOI: 10.1002/cssc.201700587
       
  • Direct Electro-oxidation of Dimethyl Ether on Pt-Cu NanoChains
    • Authors: Bar Gavriel; Ronit Sharabi, Lior Elbaz
      Abstract: In this work, new catalyst for the direct electro-oxidation of dimethyl ether (DME) was synthesized and studied using an array of techniques. One of the most prominent catalysts for this reaction, platinum copper alloy (PtCu), was synthesized in an easy and low cost approach. Structural characterizations such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and elemental analysis revealed that the synthesized PtCu nanoparticles (3 nm on average), formed homogeneous NanoChains without aggregation of metallic platinum or copper. The catalyst's activity towards electro-oxidation of DME was tested using cyclic - voltammetry (CV) and in membrane-electrode assembly (MEA) in a full cell. The catalyst performance was found to be promising. Direct DME fuel cell (DDMEFC) studied in this work has relatively high energy density, of 13.5 mW cm-1 and thus shows great potential as fuel for low power fuel cells. The electrocatalysis of the DME oxidation reaction (DOR) was compared between synthesized PtCu and commercial PtRu/C and exhibited almost double the performance with the newly synthesized catalyst.
      PubDate: 2017-06-18T21:22:08.766903-05:
      DOI: 10.1002/cssc.201700702
       
  • Co-based Active Species Molecularly Immobilized on Carbon Nanotubes for
           Oxygen Reduction Reaction
    • Authors: Sujin Kim; Dawoon Jang, Joonwon Lim, Junghoon Oh, Sang Ouk Kim, Sungjin Park
      Abstract: Hybrid systems that molecule-based active species are combined with nanoscale materials may offer valuable routes to enhance the catalytic performances for electrocatalytic reactions. Development of rationally designed, cost-effective efficient catalysts for oxygen reduction reaction (ORR) is a crucial challenge for fuel cell and metal-air battery applications. In this work, we report a novel hybrid ORR catalyst material synthesized by a well-defined reaction pathway between Co-based organometallic molecules and N-doped multiwalled carbon nanotubes (MWCNT) at room temperature. The hybrid ORR catalyst shows excellent catalytic performances with an onset potential of 0.95 V (vs. RHE), superior durability and good methanol tolerance. Chemical and structural characterizations reveal that Co-based organometallic molecules maintained the original structure of Co(acetylacetonate)2 after prolonged cycles of reaction, while coordinated to heteroatoms of MWCNT. Thorough electrochemical investigation suggests that the major catalytic active site is Co-O4-NCNT.
      PubDate: 2017-06-18T21:21:58.068842-05:
      DOI: 10.1002/cssc.201701038
       
  • Sustainable Production of o-Xylene from Biomass-Derived Pinacol and
           Acrolein
    • Authors: Yancheng Hu; Ning Li, Guangyi Li, Aiqin Wang, Yu Cong, Xiaodong Wang, Tao Zhang
      Abstract: o-Xylene (OX) is a large-volume commodity chemical that is conventionally produced from fossil fuels. Herein, we report an efficient and sustainable two-step route to OX from biomass-derived pinacol and acrolein. In the first step, the phosphotungstic acid (HPW) catalyzed pinacol dehydration in 1-ethyl-3-methylimidazolium chloride ([Emim]Cl) selectively afforded 2,3-dimethylbutadiene. The high selectivity of this reaction can be ascribed to the H-bonding interaction between Cl- and the hydroxyl group of pinacol. Besides, the stabilization of the carbocation intermediate by the surrounding anion Cl- may be another reason for the high selectivity. Notably, the good reusability of the HPW/[Emim]Cl system can reduce the waste output and production cost. In the second step, OX was selectively produced by the D-A reaction of 2,3-dimethylbutadiene and acrolein, followed by the Pd/C-catalyzed decarbonylation/aromatization cascade in a one-pot fashion. The sustainable two-step process could efficiently produce renewable OX in 79% overall yield. Analogously, biomass-derived crotonaldehyde and pinacol can also serve as the feedstocks for the production of 1,2,4-trimethylbenzene.
      PubDate: 2017-06-16T04:20:21.73826-05:0
      DOI: 10.1002/cssc.201700823
       
  • Sustainable separations of C4 hydrocarbons using microporous materials
    • Authors: Stefania Tanase-Grecea; Mascha Gehre, Zhiyong Guo, Gadi Rothenberg
      Abstract: Petrochemical refineries must separate hydrocarbons mixtures on a large scale for the production of fuels and chemicals. Most often, these hydrocarbons are separated by distillation, which is extremely energy-intensive. This high energy cost can be mitigated by developing materials that can enable efficient adsorptive separation. In this critical review, we first outline the principles of adsorptive separation. We then examine the case for C4 separations using zeolites and metal-organic frameworks (MOFs). By analysing both experimental and theoretical studies, we outline the challenges and opportunities in C4 separation, with a focus on the separation mechanisms and structure-selectivity correlations. Zeolites are commonly used as adsorbents, and in some cases can separate C4 mixtures well. The pore sizes of 8-membered-ring zeolites, for example, are in the order of the kinetic diameters of C4 isomers. Although zeolites have the advantage of a rigid and highly stable structure, this is often difficult to functionalize. MOFs are attractive candidates for hydrocarbon separation because their pores can be tailored to optimize the adsorbate-adsorbent interactions. MOF-5 and ZIF-7 show promising results in separating all C4 isomers, but breakthrough experiments under industrial conditions are needed to confirm these results. Moreover, the flexibility of the MOF structures could hamper their application under industrial conditions. All in all, adsorptive separation is a promising viable alternative, and it is likely to play an increasingly important role in tomorrow's refineries.
      PubDate: 2017-06-15T21:20:27.077112-05:
      DOI: 10.1002/cssc.201700657
       
  • Novel solid state lithium conductors for lithium metal batteries based on
           electrospun nanofibers and plastic crystal composites
    • Authors: Yundong Zhou; Xiaoen Wang, Haijin Zhu, Masahiro Yoshizawa-Fujita, Yukari Miyachi, Michel Armand, Maria Forsyth, George W. Greene, Jennifer M. Pringle, Patrick Howlett
      Abstract: Organic ionic plastic crystals (OIPCs) are a class of solid-state electrolyte with good thermal stability, non-flammability, non-volatility and good electrochemical stability. When prepared in a composite with electrospun polyvinylidene fluoride (PVdF) nanofibers, a 1:1 mixture of the OIPC N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide and LiFSI produced a free-standing, robust solid state electrolyte. These high concentration Li-containing electrolyte membranes had a transference number of 0.37 (± 0.02) and supported stable lithium symmetric-cell cycling at a current density of 0.13 mA cm-2. The effects of PVdF incorporation in the Li-containing plastic crystal were investigated for different ratios of PVdF and [Li][FSI]/[C2mpyr][FSI]. Li LiNi1/3Co1/3Mn1/3O2 cells were also prepared and cycled at ambient temperature and displayed good rate performance and stability.
      PubDate: 2017-06-15T03:20:22.086337-05:
      DOI: 10.1002/cssc.201700691
       
  • Self-assembled dendritic Pt nanostructure with high-index facets as highly
           active and durable electrocatalyst for oxygen reduction
    • Authors: Youngjin Jang; Kwang-Hyun Choi, Dong Young Chung, Ji Eun Lee, Namgee Jung, Yung-Eun Sung
      Abstract: The durability issues of Pt catalyst should be resolved for the commercialization of proton exchange membrane fuel cells. Nanocrystal structures with high-index facets have been recently focused to solve the critical durability problem of fuel cell catalysts since Pt catalysts with high-index facets can preserve the ordered surfaces without change of the original structures. However, it is very difficult to develop the effective and practical synthetic methods for Pt-based nanostructures with high-index facets. The current study describes a designed simple one-pot synthesis of self-assembled dendritic Pt nanostructures with electrochemically active and stable high-index facets. Pt nanodendrites exhibited 2 times higher ORR activity and superior durability (only 3.0 % activity loss after 10,000 potential cycles) than a commercial Pt/C. The enhanced catalytic performance was elucidated by the formation of well-organized dendritic structures with plenty of reactive interfaces among 5 nm-sized Pt particles and the co-existence of low- and high-index facets on the particles.
      PubDate: 2017-06-14T23:20:42.438481-05:
      DOI: 10.1002/cssc.201700852
       
  • Detection of Reactive Oxygen Species in AEM Fuel Cells using in situ
           Fluorescence Spectroscopy
    • Authors: Yunzhu Zhang; Javier Parrondo, Shrihari Sankarasubramanian, Vijay Ramani
      Abstract: The objectives of this study were: 1) to confirm superoxide anion radical (O₂·¯) formation, and 2) to monitor in real-time the rate of O₂·¯ generation in an operating anion exchange membrane (AEM) fuel cell using in situ fluorescence spectroscopy. 1,3-diphenlisobenzofuran (DPBF) was used as the fluorescent molecular probe due to its selectivity and sensitivity towards O₂·¯ in alkaline media. The activation energy for the in situ generation of O₂·¯ during AEM fuel cell operation was estimated to be 18.3 kJ mol-1. The rate of in situ generation of O₂·¯ correlated well with the experimentally measured loss in AEM ion-exchange capacity and ionic conductivity attributable to oxidative degradation.
      PubDate: 2017-06-14T23:20:22.58716-05:0
      DOI: 10.1002/cssc.201700760
       
  • Mechanochemical Ring-Opening Polymerization of Lactide: Liquid-Assisted
           Grinding for the Green Synthesis of Poly(lactic acid) with High Molecular
           Weight
    • Authors: Nuri Ohn; Jihoon Shin, Sung Sik Kim, Jeung Gon Kim
      Abstract: A mechanochemical polymerization of lactide is developed using ball milling. Mechanical energy from the collisions between the balls and the vessel efficiently promoted an organic-base-mediated metal- and solvent-free solid-state polymerization. Investigations on the parameters of the ball-milling synthesis revealed that the degree of lactide ring-opening polymerization could be modulated by the ball-milling time, vibration frequency, mass of the ball media, and liquid-assisted grinding. Especially, liquid-assisted grinding was found to be an important factor for achieving a high degree of mechanochemical polymerization. While polymer-chain scission from the strong collision energy prevented a mechanical-force-driven high-molecular-weight polymer synthesis, the addition of only a small amount of liquid provided a sufficient energy dissipation. Thus, poly(lactic acid) with a molecular weight over 1 x 10^5 g/mol was successfully obtained by the green mechanochemical approach.
      PubDate: 2017-06-14T09:21:16.855448-05:
      DOI: 10.1002/cssc.201700873
       
  • Copper-Catalyzed Oxidative Dehydrogenative C(sp3)-H Bond Amination of
           (Cyclo)Alkanes using NH-Free Heterocycles as Amine Sources
    • Authors: Chang-Sheng Wang; Xiao-Feng Wu, Pierre H Dixneuf, Jean-Francois Soule
      Abstract: A copper-catalyzed oxidative C(sp3)-H/N-H coupling of NH-heterocycles with affordable (cyclo)alkanes was developed. This protocol involved C(sp3)-N bond formation via a radical pathway generated by a homolytic cleavage of di-tert-butyl peroxide and trapping of the radical(s) by copper catalysts. The reaction tolerated a series of functional groups, such as bromo, fluoro, ester, ketone, nitrile, methyl and methoxy. NH-free indoles, pyroles, pyrazoles, indazoles and benzotriazoles have been successfully N-alkylated.
      PubDate: 2017-06-14T04:20:26.762557-05:
      DOI: 10.1002/cssc.201700783
       
  • Enhanced Interfacial Charge Transfer on WO3 Photoanode by Molecular
           Iridium Catalyst
    • Authors: Haili Tong; Yi Jiang, Qian Zhang, Jialing Li, Wenchao Jiang, Donghui Zhang, Na Li, Lixin Xia
      Abstract: The rational design of active photoanodes for photoelectrochemical (PEC) water splitting is crucial for future applications in sustainable energy conversion. A combination of catalysts with photoelectrodes is generally required to improve surface kinetics and suppress surface recombination. In this study, we present an iridium complex (Ir-PO3H2) modified WO3 photoanode (WO3+Ir-PO3H2) for PEC water oxidation. When the Ir-based molecular catalyst (Ir-PO3H2) is anchored to a WO3 electrode, the photoanode shows a significant improvement both in photocurrent and faradaic efficiency compared to bare WO3. Under simulated sunlight illumination (AM 1.5G, 100 m Wcm−2) with an applied bias of 1.23 V vs. RHE, the photoanode exhibits a photocurrent of 1.16 mA cm−2 in acidic conditions, which is double that of bare WO3. The faradaic efficiency is promoted from 56% to 95%. Kinetic studies reveal that Ir-PO3H2 exhibits a different interfacial charge transfer mechanism on the WO3 photoanode for PEC water oxidation compared to iridium oxide (IrOx). Ir-PO3H2, as a water oxidation catalyst, can accelerate the surface charge transfer through rapid surface kinetics.
      PubDate: 2017-06-14T03:22:49.680737-05:
      DOI: 10.1002/cssc.201700721
       
  • Oxygen Vacancy Engineering of Co3O4 Nanocrystals via Constructing Coupled
           Interface with Metal Supports for Promoting Water Oxidation in Neutral
           Electrolyte
    • Authors: Jun-Jun Zhang; Hong-Hui Wang, Tian-Jian Zhao, Ke-Xin Zhang, Xiao Wei, Xin-Hao Li, Shin-Ichi Hirano, Jie-Sheng Chen
      Abstract: Oxygen vacancies could help to capture oxygen-containing species and act as active centers for oxygen evolution reaction (OER). Unfortunately, effective methods for generating a rich amount of oxygen vacancies on the surface of various nanocatalysts are rather limited. In this work, we described an effective way to generate oxygen vacancy-rich surface of transition metal oxides, exemplified with Co3O4 here, simply by constructing highly coupled interface of ultra-fine Co3O4 nanocrystals and metallic Ti. Impressively, the amounts of oxygen vacancy on the surface of Ti@Co3O4 far surpassed the reported values of the Co3O4 modified even under highly critical conditions. The Ti@Co3O4 electrode could provide a current density of 23 mA cm-2 at an OER overpotential of 570 mV, low Tafel slope and excellent durability in neutral medium. Due to the formation of a large amount of oxygen vacancies as the active centers for OER on the surface, the TOF value of the Ti@Co3O4 electrode was optimized to be 3238 h-1 at an OER overpotential of 570 mV, which is 380 times of that of the state-of-the-art non-noble nanocatalysts in the literature.
      PubDate: 2017-06-14T02:20:34.050457-05:
      DOI: 10.1002/cssc.201700779
       
  • Recent Advances in Bismuth Based Nanomaterials for Photoelectrochemical
           Water Splitting
    • Authors: Swhetha S M Bhat; Ho Won Jang
      Abstract: In recent years bismuth based nanomaterials are drawing considerable interest as potential candidates for photoelectrochemical (PEC) water splitting due to their narrow band gap, nontoxicity and low cost. The unique electronic structure with well dispersed valance band comprising of Bi 6s and O 2p orbital in the bismuth based materials offers suitable band gap to harvest visible light. This review presents the significant advancements in exploiting bismuth based materials for solar water splitting. An overview of different strategies employed and new ideas adopted to improve the PEC performance are discussed for these materials. Morphology control, construction of heterojunctions, doping and co-catalysts loading are the several approaches implemented to improve the efficiency of the solar water splitting. The key issues are identified and guidelines are suggested to rationalize the design of efficient bismuth based materials for sunlight driven water splitting.
      PubDate: 2017-06-13T22:20:49.128141-05:
      DOI: 10.1002/cssc.201700633
       
  • Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for
           Continuous-Flow Nanocatalysis
    • Authors: Hirotaka Koga; Naoko Namba, Tsukasa Takahashi, Masaya Nogi, Yuta Nishina
      Abstract: The Back Cover picture shows a renewable wood pulp paper reactor for highly efficient, green, and sustainable chemical manufacturing. This “paper reactor” contains hierarchical micro/nanoscale pores tailored from wood pulp fibers, which can act as both convective-flow and rapid-diffusion channels for efficient access of reactants to metal nanoparticle catalysts anchored within the paper reactor, leading to dramatically improved reaction efficiency. More details can be found in the Communication by Koga et al. (
      DOI : 10.1002/cssc.201700576).
      PubDate: 2017-06-12T08:00:32.831284-05:
       
  • Electrospinning Hetero-Nanofibers of Fe3C-Mo2C/Nitrogen-Doped-Carbon as
           Efficient Electrocatalysts for Hydrogen Evolution
    • Authors: Huanlei Lin; Wenbiao Zhang, Zhangping Shi, Minwei Che, Xiang Yu, Yi Tang, Qingsheng Gao
      Abstract: Invited for this month′s cover is the group of Qingsheng Gao at Jinan University. The image shows the synergistically improved kinetics on Fe3C-Mo2C hetero-interfaces for hydrogen evolution, as illustrated by the easily passed hurdles in hurdle race. The Full Paper itself is available at 10.1002/cssc.201700207.“The meteoric particles stride the hurdles toward the bright future…” 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.201700207. View the Front Cover here: 10.1002/cssc.201700832.
      PubDate: 2017-06-12T08:00:31.878721-05:
      DOI: 10.1002/cssc.201700833
       
  • Electrospinning Hetero-Nanofibers of Fe3C-Mo2C/Nitrogen-Doped-Carbon as
           Efficient Electrocatalysts for Hydrogen Evolution
    • Authors: Huanlei Lin; Wenbiao Zhang, Zhangping Shi, Minwei Che, Xiang Yu, Yi Tang, Qingsheng Gao
      Abstract: The Cover picture shows a hurdle race with different hurdles corresponding to the varied energy barriers of the hydrogen evolution reaction. In this work, electrospinning followed by pyrolysis is introduced to construct Fe3C-Mo2C/N-doped carbon hetero-nanofibers and accomplish the synergistically enhanced elementary steps, as illustrated by the low hurdles in the runway. Such synergy results in the benchmarking performance of noble-metal-free electrocatalysts. This study opens up new opportunities to explore high-performance catalysts through interfacial engineering. More details can be found in the Full Paper by Lin et al. (
      DOI : 10.1002/cssc.201700207).
      PubDate: 2017-06-12T08:00:22.709721-05:
       
  • Process Intensification for Cellulosic Biorefineries
    • Authors: Sunitha Sadula; Abhay Athaley, Weiqing Zheng, Marianthi Ierapetritou, Basudeb Saha
      Abstract: The Inside Cover picture shows multipurpose use of sugars produced from varieties of advantageous sourced lignocellulosic biomass by an integrated one-step process. This new energy- and water-efficient process yields up to 95 % theoretical amount of sugars in an inorganic salt solution. The high efficiency and easiness of separation of the products create favorable economics that can enable bio-based products that are cost-competitive and sustainable. More details can be found in the Communication by Sadula et al. (
      DOI : 10.1002/cssc.201700183).
      PubDate: 2017-06-12T08:00:18.72625-05:0
       
  • Stable Organic Radicals in Lignin; A Review
    • Authors: Dimitris Argyropoulos; Shradha S Patil
      Abstract: Lignin and the quest for the origin of stable organic radicals in it have seen numerous developments. Although there have been various speculations over the years on the formation of these stable radicals, researchers have not been to arrive at a solid, unequivocal hypothesis that applies to all treatments and types of lignin. The extreme complexity of lignin and its highly aromatic, crosslinked, branched and rigid structure has made such efforts rather cumbersome. Since the early fifties, researchers in this field have dedicated their efforts to establish methods for the detection and determination of spin content, theoretical simulations, and reactions on model compounds and spin trapping studies. While a significant amount of published research is available on lignin or its model compounds and the reactive intermediates involved during various chemical treatments (pulping, bleaching, extractions, chemical modifications, etc.) the literature provides a limited view on the origin, nature, and stability of such radicals. Consequently, this review is focused on examining the origin of such species in lignin, factors affecting their presence, reactions involved in their formation, and methods for their detection.
      PubDate: 2017-06-12T07:15:20.852255-05:
      DOI: 10.1002/cssc.201700869
       
  • Influence of sulfuric acid on the performance of ruthenium-based catalysts
           in the liquid-phase hydrogenation of levulinic acid to γ-valerolactone
    • Authors: Jamal Ftouni; Homer Genuino, Ara Munoz-Murillo, Pieter Bruijnincx, Bert Weckhuysen
      Abstract: The presence of biogenic or process-derived impurities poses a major problem on the efficient catalytic hydrogenation of biomass-derived levulinic acid to γ-valerolactone, hence, studies on their influence on catalyst stability are now required. Here, we investigate the influence of sulfuric acid as feed impurity on the performance of Ru-based heterogeneous catalysts, including Ru/ZrO2 and mono- and bimetallic Ru-on-carbon catalysts in dioxane as solvent. The carbon-supported Ru catalysts proved to be very sensitive to minor amounts of this impurity. In stark contrast, Ru/ZrO2 showed a remarkable stability in the presence of the same impurity, which is attributed to the sulfate ion adsorption capacity of the support. Preferential sulfate adsorption onto the surface of ZrO2 effectively protects the Ru active phase from deactivation by sulfur poisoning. A simple catalyst regeneration strategy proved to be effective in removing adsorbed impurities, allowing for efficient catalyst recycling.
      PubDate: 2017-06-11T21:20:55.319737-05:
      DOI: 10.1002/cssc.201700768
       
  • An Efficient and Versatile Catalyst for Carbon Dioxide Fixation into
           Cyclic Carbonates
    • Authors: Antonio Otero; Javier Martinez, Juan Fernandez-Baeza, Luis F Sanchez-Barba, Jose A Castro-Osma, Agustin Lara-Sanchez
      Abstract: A new heteroscorpionate lanthanum complex has shown exceptional catalytic activity for the synthesis of cyclic carbonates from epoxides and carbon dioxide. The new catalyst system also promotes the reaction of bio-based epoxides to give an important class of bis(cyclic carbonates) that can be further used for the production of bio-derived non-isocyanate polyurethanes. The catalytic process requires low catalyst loading and mild reaction conditions for the synthesis of a wide range of cyclic carbonates.
      PubDate: 2017-06-09T10:55:05.886397-05:
      DOI: 10.1002/cssc.201700898
       
  • Defect chemistry, electrical properties and evaluation of new ox-ides
           Sr2CoNb1-xTixO6-δ (0≤x≤1) as cathode materials for Solid Oxide Fuel
           Cells
    • Authors: M. Teresa Azcondo; Mercedes Yuste, Juan Carlos Perez Flores, Daniel Muñoz Gil, Susana García Martín, Alvaro Muñoz Noval, Inés Puente Orench, Flaviano García Alvarado, Ulises Amador
      Abstract: : The perovskite series Sr2CoNb1-xTixO6-δ (0≤x≤1) is investigated in the full compositional range to assess its potential as cathode material for solid state fuel cell (SOFC). The variation of transport properties and thus, the area specific resistances (ASR) are explained by a detailed investigation of the defect chemistry. Increasing titanium content from x=0 to x=1 produces both oxidation of Co3+ to Co4+ (from 0% up to 40%) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit) though each charge compensation mechanism predominates in different compositional ranges. Neutron diffraction reveals that samples with high Ti-contents lose a significant amount of oxygen on heating above 600K. Oxygen is partially recovered on cooling since the oxygen release and uptake show noticeably different kinetics. The complex defect chemistry of these compounds, together with the compositional changes upon heating-cooling cycles and atmospheres produce, a complicated behavior of electrical conductivity. Cathodes containing Sr2CoTiO6-δ display low ASR values, 0,13 Ωcm2 at 973 K, comparable to those of the best compounds reported so far, being a very promising cathode material for SOFC.
      PubDate: 2017-06-08T05:20:25.770706-05:
      DOI: 10.1002/cssc.201700648
       
  • Isohexide Dinitriles: a versatile family of renewable platform chemicals
    • Authors: Jing Wu; Shanmugam Thiyagarajan, Célia Fonseca Guerra, Pieter Eduard, Martin Lutz, Bart A. J. Noordover, Cor E. Koning, Daan S. van Es
      Abstract: New 2/5 1-carbon extended isohexide building blocks are now synthetically accessible by a convenient, selective base-catalyzed epimerization of the corresponding dinitriles. Kinetic experiments using the strong organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) show that all three possible isohexide dinitrile isomers are in a dynamic equilibrium. An epimerization mechanism is proposed, based on DFT calculations. Structural identification of all three possible isomers is based on NMR analysis as well as single crystal x-ray crystallography. DFT calculations confirmed that the observed crystal structures are indeed the lowest energy conformers of these isohexide derivatives.
      PubDate: 2017-06-07T05:20:38.270165-05:
      DOI: 10.1002/cssc.201700617
       
  • Greening the processes in MOFs synthesis and MOFs-involved sustainable
           catalysis
    • Authors: Junying Chen; Kui Shen, Yingwei Li
      Abstract: Given the shortage of sustainable resources and the arising serious environment impact in recent decades, the demand for clean technologies and sustainable sources is of great interest to worldwide researchers. As we look into the fields of energy saving and environment cleaning, the key point is the development of efficient catalysts, not only in the way of facile synthesis methods, but also the utilization of such catalysts in benign manners. This work reviews the dedication of metal-organic frameworks (MOFs) and MOF-based materials to these fields. The definition of MOFs and MOF-based materials will be primarily introduced followed by the brief description of the characterization and stability of MOF related materials under applied conditions. The greening processes of MOFs synthesis will be illustrated then, catalogued by benign solvents and conditions, and green precursors of MOFs. Further, the suitable application in sustainable catalysis will be summarized, focusing on several typical atom economic reactions, e.g., the direct introduction of H2 and O2, and C-C bond formation. The approaches towards reducing CO2 emitting by MOF-based catalysts will be described with special emphasis on CO2 fixation and CO2 reduction. In addition, driven by the explosive growth of energy consumption from last century, researches on biomass, which are renewable alternatives to fossil fuels and sustainable carbon feedstock for chemicals production, have been exploited. The advanced progress of biomass-related transformation will be illustrated. The fundamental insight into the nature of MOFs-based materials as constitutionally easily-recoverable heterogeneous catalysts and as supports to inducting varied active sites is thoroughly discussed. Finally, the facing challenges of the development in this field and the outlook for future research will be presented.
      PubDate: 2017-06-06T22:20:36.497952-05:
      DOI: 10.1002/cssc.201700748
       
  • Ionic Liquid-Assisted Microwave Synthesis of Solid Solutions of Perovskite
           Sr1-xBaxSnO3 for Photocatalytic Applications
    • Authors: Anja Verena Mudring; Tarek Alammar, Igor Slowing, Jim Anderegg
      Abstract: For the first time nanocrystal perovskite Sr1-xBaxSnO3 photocatalysts were prepared by means of microwave synthesis in an ionic liquid (IL) and subsequent heat-treatment. The influence of the Sr/Ba substitution on the structure, crystallization, morphology and, in the end, the photocatalytic efficiency of SrSnO3 was investigated. Based on the structure characterization using X-ray diffraction, with increasing Ba content in the lattice of SrSnO3 a symmetry increase from the orthorhombic perovskite structure for SrSnO3 to the cubic for BaSnO3 was observed. Analysis of the sample morphology using SEM reveals that the Sr1-xBaxSnO3 samples favor the formation of nanorods (500 nm - 5 μm in diameter and several micrometers in length). The band gap decreases with increasing Ba2+ content from 3.85 eV to 3.19 eV. Furthermore, the photocatalytic properties were evaluated by the hydroxylation of terephthalic acid (TA). The order of the activities of TA hydroxylation was Sr0.8Ba0.2SnO3> SrSnO3> BaSnO3> Sr0.6Ba0.4SnO3> Sr0.2Ba0.8SnO3. The highest photocatalytic activity was observed for Sr0.8Ba0.2SnO3 which can be attributed to the synergistic impacts of the modification of crystal structure and morphology, the relatively large surface area associated with the small crystallite size and suitable band gap size as well as band edge position.
      PubDate: 2017-06-06T22:20:33.920251-05:
      DOI: 10.1002/cssc.201700615
       
  • Boosting the supercapacitance of nitrogen-doped carbon by tuning surface
           functionalities
    • Authors: Jasper Biemolt; Ilse M. Denekamp, Thierry K. Slot, Gadi Rothenberg, David Eisenberg
      Abstract: We report that the specific capacitance of a highly porous, nitrogen-doped carbon is nearly tripled by orthogonal optimization of microstructure and surface chemistry. First, the carbons' hierarchical pore structure and specific surface area were tweaked by controlling the temperature and sequence of thermal treatments. The best process (pyrolysis at 900 °C, washing, and a second annealing at 1000 °C) yielded carbons with a specific capacitance of 117 F/g - nearly double that of a carbon made by a typical, single-step synthesis at 700 °C. Following the structural optimization, the surface chemistry of the carbons was enriched by applying an oxidation routine based on nitric and sulfuric acids in 1:4 ratio, at two different treatment temperatures (0 °C and 20 °C) and along different treatment times. The optimal treatment times are 4 h at 0 °C and only 1 h at 20 °C. Overall, specific capacitance nearly tripled relative to the original carbon, reaching to 168 F/g. The inherent nitrogen doping of the carbon comes into interplay with the acid-induced surface functionalization, creating a mixture of oxygen- and nitrogen-oxygen functionalities. The evolution of surface chemistry was carefully followed by X-ray photoelectron spectroscopy and by N2 sorption porometry, revealing stepwise surface functionalization and simultaneous carbon etching. Overall, these processes are responsible for the peak-shaped capacitance trends in the carbons.
      PubDate: 2017-06-06T10:15:21.602775-05:
      DOI: 10.1002/cssc.201700902
       
  • Ni@Ni(OH)2 Core-Shell Particles Partially Covering Silicon Photoanode for
           
    • Authors: Shicheng Yan; Zhe Xu, Zhan Shi, Lang Pei, Zhengbin Gu, Zhigang Zou
      Abstract: One main barrier for enhancing solar energy conversion by photoelectrochemical (PEC) water splitting devices is the charge separation and transport efficiency at the interface region of the photoanode and electrolyte. Here, we electrodeposited the core-shell structured Ni@Ni(OH)2 nanoparticles on the surface of n-type Si photoanode with island distribution. We found that the Schottky barrier between Ni and Si is sensitive to the thickness of Ni(OH)2 shell. The photovoltage output of the photoanode increases with increasing the thickness of Ni(OH)2 shell, closely associating with the interaction between Ni and Ni(OH)2 that depends on the electrolyte screening effect and p-type feature of Ni(OH)2 layer. As a result, the Ni@Ni(OH)2 core-shell nanoparticles with appropriate shell thickness coupling with n-Si photoanode can promote the separation of photogenerated carriers and improve the charge injection efficiency to nearly 100%, thus affording a onset potential of 1.03 VRHE and saturated current density of 36.4 mA·cm-2. The proposed interface manipulation method of varying the thickness of the electrocatalyst in our study may open a new route to development of high-performance PEC devices.
      PubDate: 2017-06-06T08:21:26.983505-05:
      DOI: 10.1002/cssc.201700825
       
  • Intensified biobutanol recovery using zeolites with complementary
           selectivity
    • Authors: Stijn Van der Perre; Pierre Gelin, Benjamin Claessens, Ana Martin-Calvo, Julien Cousin Saint Remi, Tim Duerinck, Gino V. Baron, Miguel Palomino, Ledys Y. Sanchez, Susana Valencia, Jin Shang, Ranjeet Singh, Paul A. Webley, Fernando Rey, Joeri Denayer
      Abstract: A vapor phase adsorptive recovery process is proposed as an alternative way to isolate biobutanol from acetone-butanol-ethanol (ABE) fermentation media, offering several advantages compared to liquid phase separation. The effect of water, which is still present in large quantities in vapor phase, on the adsorption of the organics could be minimized by using hydrophobic zeolites. Shape selective all-silica zeolites CHA and LTA were prepared and evaluated via single component isotherms and breakthrough experiments. These zeolites show an opposite selectivity; adsorption of ethanol was favorable on all-silica CHA, while the LTA topology had clear preference for butanol. The molecular sieving properties of both zeolites allowed to easily eliminate acetone from the mixture. The molecular interaction mechanisms were studied by density functional theory (DFT) simulations. Effect of mixture composition, humidity and total pressure of the vapor stream on the selectivity and separation behavior was investigated. Desorption profiles were studied to maximize butanol purity and recovery. The combination of LTA with CHA type zeolites (Si-CHA or SAPO-34) in sequential adsorption columns with alternating adsorption and desorption steps allows to obtain butanol in unpreceded purity and recovery. A butanol purity of 99.7 mole% could be obtained at nearly complete butanol recovery, demonstrating the effectiveness of this technique for biobutanol separation processes.
      PubDate: 2017-06-06T06:15:20.378238-05:
      DOI: 10.1002/cssc.201700667
       
  • High Performance Ruthenium Sensitizers Containing Imidazoliums as
           Counterions for the Efficient Dye-Sensitization in Water
    • Authors: Xiaoyu Li; Shiqing Li, Ge Gao, Di Wu, Jingbo Lan, Ruilin Wang, Jingsong You
      Abstract: A new type of water-soluble ruthenium sensitizers containing imidazoliums as counterions, coded [DMPI]2-Ru and [DMHI]2-Ru, has been developed, which can be efficiently adsorbed on TiO2 in aqueous solution. Owing to the good thermal stability of imidazolium, [DMPI]2-Ru adsorbed on TiO2 possesses a higher decomposition temperature than N719. When using organic solvent-based I−/I3− electrolytes, the solar cell based on [DMPI]2-Ru-sensitized TiO2 in water shows a high power conversion efficiency (PCE) up to 10.2%, which is higher than that of N719 (9.9%) under the common condition of the dye-sensitization process in organic solvent. In comparison with [DMPI]2-Ru, [DMHI]2-Ru with a relatively poorer water-solubility shows a smaller dye adsorption amount on TiO2, thus giving a lower PCE of 9.4%. From the viewpoint of safety and environmental impact, the fabrication of DSSCs by fully using water as solvent is undoubtedly a more ideal strategy. Although the [DMPI]2-Ru-based device fabricated by using water as the solvent of both the dye-sensitization process and electrolytes gives a relatively low efficiency, it provides a promising approach for the practical application of DSSCs.
      PubDate: 2017-06-04T21:20:41.193971-05:
      DOI: 10.1002/cssc.201700579
       
  • Fe2PO5-Encapsulated Reverse Energetic ZnO/Fe2O3 Heterojunction Nanowire
           for Enhanced Photoelectrochemical Oxidation of Water
    • Authors: Dong-Dong Qin; Cai-Hua He, Yang Li, Antonio C. Trammel, Jing Gu, Jing Chen, Yong Yan, Duo-Liang Shan, Qiu-Hong Wang, Jing-Jing Quan, Chun-Lan Tao, Xiao-Quan Lu
      Abstract: Zinc oxide is regarded as a promising candidate for application in photoelectrochemical water oxidation due to its higher electron mobility. However, its instability under alkaline conditions limits its application in a practical setting. Herein, we demonstrate an easily achieved wet-chemical route to chemically stabilize ZnO nanowires (NWs) by protecting them with a thin layer Fe2O3 shell. This shell, in which the thickness can be tuned by varying reaction times, forms an intact interface with ZnO NWs, thus protecting ZnO from corrosion in a basic solution. The reverse energetic heterojunction nanowires are subsequently activated by introducing an amorphous iron phosphate, which substantially suppressed surface recombination as a passivation layer and improved photoelectrochemical performance as a potential catalyst. Compared with pure ZnO NWs (0.4 mA cm−2), a maximal photocurrent of 1.0 mA cm−2 is achieved with ZnO/Fe2O3 core–shell NWs and 2.3 mA cm−2 was achieved for the PH3-treated NWs at 1.23 V versus RHE. The PH3 low-temperature treatment creates a dual function, passivation and catalyst layer (Fe2PO5), examined by X-ray photoelectron spectroscopy, TEM, photoelectrochemical characterization, and impedance measurements. Such a nano-composition design offers great promise to improve the overall performance of the photoanode material.A passive catalyst' A Fe2O3 shell was grown onto a ZnO core to protect the surface from corrosion and increase the charge-separation efficiency. PH3 treatment onto the core–shell nanowire creates a Fe2PO5 with dual functionality: a catalyst and passivating overlayer.
      PubDate: 2017-06-01T13:32:13.65886-05:0
      DOI: 10.1002/cssc.201700501
       
  • Hyperspectral imaging to determine the properties and homogeneity of
           renewable carbon materials
    • Authors: Mikko Mäkelä; Paul Geladi
      Abstract: Hyperspectral imaging within the NIR region offers a fast and reliable way for determining the properties of renewable carbon materials. The chemical information provided by a spectrum combined with the spatial information of an image allows mathematical operations that can be performed in both the spectral and spatial domains. In this work we show that hyperspectral NIR imaging can be successfully used to determine the properties of hydrothermally prepared carbon on the material and pixel levels. Materials produced from different feedstocks or prepared under different temperatures can also be distinguished, and their homogeneity can be evaluated. As hyperspectral imaging within the NIR region is non-destructive and requires very little sample preparation, it can be used for controlling the quality of renewable carbon materials destined for a wide range of different applications.
      PubDate: 2017-05-31T05:30:41.790002-05:
      DOI: 10.1002/cssc.201700777
       
  • Additives Based on Green Chemistry for Recyclable Epoxy Matrice
    • Authors: Martin Lahn Henriksen; Jens Bomholdt Ravnsbæk, Morten Bjerring, Thomas Vosegaard, Kim Daasbjerg, Mogens Hinge
      Abstract: Epoxy based thermosets are one of the most popular material matrices in many industries and significant environmental benefits can be obtained by development of a recyclable epoxy variant of this widely utilized material. This paper demonstrates that addition of a biobased additive to a commercial epoxy system leads to a crosslinked material that can be fractionated under mild and environmentally benign conditions. The novel material has been analyzed by FT-IR and solid state NMR. Furthermore, modified epoxy matrices with low additive concentrations are demonstrated to have similar mechanical and thermal properties when benchmarked against the commercial available epoxy matrix. Thus, additives and fractionation based on green chemistry has been demonstrated and a recyclable epoxy matrix has been developed.
      PubDate: 2017-05-30T12:20:23.309149-05:
      DOI: 10.1002/cssc.201700712
       
  • Bottom-up construction of TEMPO built-in porous organic frameworks as a
           cathode for lithium-sulphur batteries
    • Authors: Baolong Zhou; Xiang Hu, Guang Zeng, Shiwu Li, Zhenhai Wen, long chen
      Abstract: Two redox-active radical (TEMPO) built-in porous organic frameworks (POFs), which feature hierarchical porous structures, were synthesized via a facile bottom-up strategy and were studied as cathode materials for lithium-sulphur (Li-S) batteries. The sulphur loading in these two POFs can reach up to 61% benefitting from their large pore volume. For the existence of highly densed docking sites of TEMPO, sulphur could be covalently restrained within the porous networks and efficiently inhibited the shuttle effect, therefore significantly improving the cycling performance. The TPE-TEMPO-POF-S composites deliver a capacity beyond 470 mAh g-1 after 200 cycles with a coulombic efficiency of around 100% at the current rate of 0.1 C. Furthermore, the sulphur embedded TEMPO-POFs show excellent rate capability with limited capacity loss at varied rate from 0.1 to 1C.
      PubDate: 2017-05-29T22:20:25.219543-05:
      DOI: 10.1002/cssc.201700749
       
  • Ionic Liquid/Metal Organic Framework Composites: From Synthesis to
           Applications
    • Authors: Pelin Kinik; Alper Uzun, Seda Keskin
      Abstract: Metal organic frameworks (MOFs) have been widely studied in different applications since their first synthesis due to their fascinating properties such as large surface areas, high porosities, tunable pore sizes, acceptable thermal and chemical stabilities. Ionic liquids (ILs) have been recently incorporated into the pores of MOFs as cavity occupants to change the physicochemical properties and gas affinities of MOFs. Several recent studies have shown that IL-incorporated MOF composites show superior performances compared to pristine MOFs in various fields such as gas storage, adsorption and membrane-based gas separation, catalysis and ionic conductivity. In this review, we address the recent advances in syntheses of IL-incorporated MOFs and provide a comprehensive overview on their applications. Opportunities and challenges of using IL/MOF composites in many applications were reviewed and requirements for the utilizations of these composite materials in real industrial processes were discussed to define the future directions in this field.
      PubDate: 2017-05-29T04:27:51.756365-05:
      DOI: 10.1002/cssc.201700716
       
  • High Efficiency Perovskite Solar Cell Based on Poly (3-hexylthiophene)
           (P3HT): The Influence of P3HT Molecular Weight and Mesoscopic Scaffold
           Layer
    • Authors: Narges Yaghoobi Nia; Fabio Matteocci, Lucio Cina, Aldo Di Carlo
      Abstract: In this work, we investigated the effect of the Molecular Weight (MW) of Poly 3-hexylthiophene (P3HT) hole transporting material on the performance of perovskite solar cells (PSCs). We found that, by increasing the MW, the photovoltaic performances of the cells are enhanced leading to an improvement of the overall efficiency. P3HT-based PSCs with a MW of 124 kDa can achieve an overall average efficiency of 16.2%, double with respect to the ones with a MW of 44 kDa. Opposite to the Spiro-OMeTAD-based PSCs, photovoltaic parameters of the P3HT-based devices are enhanced by increasing the mesoporous TiO2 layer thickness from 250 nm to 500 nm. Moreover, for a Titania scaffold layer thickness of 500 nm the efficiency of P3HT-based PSCs with high MW is larger than the Spiro-OMeTAD based PSCs with the same scaffold layerthickness. Recombination reactions of the devices are also investigated by voltage decay and electrochemical impedance spectroscopy. We found that the relation between P3HT MW and cell performance is related to the reduction of charge recombination and to the increase of the P3HT light absorption by increasing the MW.
      PubDate: 2017-05-28T21:20:31.210613-05:
      DOI: 10.1002/cssc.201700635
       
  • Mapping the free energy of lithium solvation in the protic ionic liquid
           Ethylammonuim Nitrate: A metadynamics study
    • Authors: Ali Kachmar; Marcelo Carignano, Teodoro Laino, Marcella Iannuzzi, Jürg Hutter
      Abstract: The understanding of lithium solvation and transport in ionic liquids is important due to the possible applications in electrochemical devices. Using first principles simulations aided with the metadynamics approach we study the free energy landscape for lithium at infinite dilution conditions in ethylammonium nitrate, a protic ionic liquid. We analyze the local structure of the liquid around the lithium cation and find a quantitative picture in agreement with experimental findings. Our simulations show that the lowest two free energy minima correspond to conformations with the lithium solvated either by 3 or 4 nitrates ions with a transition barrier between them of 0.2 eV. Other less probable conformations having a different solvation pattern are also investigated.
      PubDate: 2017-05-26T00:25:29.763862-05:
      DOI: 10.1002/cssc.201700510
       
  • Metal-organic Compound Branched MoS2 for Achieving High Performance
           Perovskite Solar cells
    • Authors: Ruina Dai; Yangyang Wang, Jie Wang, Xianyu Deng
      Abstract: MoS2 as a graphene-like 2D material shows a large potential to replace even overcome graphene in various important applications due to its perfect properties of electrical, optical, frictional, and tunable band gap. However, low solubility in the most of common solvents makes it difficult to prepare via a simple solution process. Here we introduce a metalorganic compound to modify MoS2. Phenyl acetylene silver (PAS) functionalized MoS2 compound is easily dispersed in the solvent of DMF and water. A conductive polymer PEDOT: PSS blend with the MoS2 leads to a significant enhancement of the performance of planar heterojunction perovskite solar cells. The solar cells have a high power conversion efficiency of 16.47% as well as largely increased stability. This provides a feasible method on large-scale yield of the MoS2 for wide applications in various electric devices.
      PubDate: 2017-05-25T21:20:28.148643-05:
      DOI: 10.1002/cssc.201700603
       
  • Brownmillerite-type Ca2FeCoO5 as a Practicable Oxygen Evolution Reaction
           Catalyst
    • Authors: Etsushi Tsuji; Teruki Motohashi, Hiroyuki Noda, Damian Kowalski, Yoshitaka Aoki, Hajime Tanida, Junji Niikura, Yukinori Koyama, Masahiro Mori, Hajime Arai, Tsutomu Ioroi, Naoko Fujiwara, Yoshiharu Uchimoto, Zempachi Ogumi, Hiroki Habazaki
      Abstract: Here, we report remarkable oxygen evolution reaction (OER) catalytic activity of brownmillerite (BM)-type Ca2FeCoO5. The OER activity of this oxide is comparable to or beyond those of the state-of-the-art perovskite (PV)-catalyst Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and a precious-metal catalyst RuO2, emphasizing the importance of the characteristic BM structure with multiple coordination environments of transition metal (TM) species. Also, Ca2FeCoO5 is obviously advantageous in terms of expense/laboriousness of the material synthesis. These facts make this oxide a promising OER catalyst used in many energy conversion technologies such as metal-air secondary batteries and hydrogen production from electrochemical/photocatalytic water splitting.
      PubDate: 2017-05-25T00:20:22.793569-05:
      DOI: 10.1002/cssc.201700499
       
  • Understanding the limiting factors of solvent annealed Small molecule bulk
           heterojunction organic solar cells from a chemical perspective
    • Authors: Aurelien Viterisi; Daniel Fernandez, Vijay Kumar Challuri, James william Ryan, Eugenia Martinez-Ferrero, Francesc Guispert-Guirado, Marta Martinez, Eduardo Escudero, Caterina Stenta, Lluis Francisco Marsal, Emilio Palomares
      Abstract: A detailed account on the limiting factors of solvent annealed bulk-heterojunction small molecule organic solars cell is given. This account is based on the extensive characterization of solar cell devices made from a library of five diketopyrolopyrole (DPP) donor dyes. Their chemical structure is designed in such a way as to provide insights on the energetics of solar cell active layer microstructure formation. Numerous chemical and physical properties of the active layers are assessed and interrelated such as light absorption, molecular packing in the solid state, crystal-forming properties in thin films, charge carrier mobility and charge carrier recombination kinetics. A myriad of characterization techniques are used such as UV-Vis absorption, photoluminescence, X-ray diffraction (XRD), AFM, photo-induced transient measurements which provide information on optical properties of the active layers, morphology and recombination kinetics. Consequently, a mechanism for the solvent vapour annealing-assisted formation of crystalline domains of donor molecules in the active layer is proposed, and the microstructure features are related to the J-V characteristics of the devices. According to this model, the crystalline phase in which the donor crystallize in the active layer is the key determinant in directing the formation of the microstructure.
      PubDate: 2017-05-24T10:20:27.604284-05:
      DOI: 10.1002/cssc.201700440
       
  • A strategy to enhance the efficiency of quantum dot sensitized solar cells
           by decreasing the electron recombinations with polyoxometalate/TiO2 as the
           electronic interface layer
    • Authors: Li Chen; Wei-Lin Chen, Jian-Ping Li, Jia-Bo Wang, En-Bo Wang
      Abstract: The serious electron recombination occurring in TiO2/quantum dot sensitizer/electrolyte interface is the key reason for hindering the further efficiency improvement of QDSCs. Polyoxometalate(POM) can be as electron transfer media to decreasing electron recombination of photoelectric device, which is due to the excellent oxidation reduction properties and thermostability. So in this paper, POM/TiO2 electronic interface layer prepared by a simple layer-by-layer self-assembly method is added between FTO and mesoporous TiO2 in the photoanode of the QDSCs, and their effects on the photovoltaic performance are systematically investigated. The photovoltaic experimental results and electron transmission mechanism explanation show that POM/TiO2 electronic interface layer in the QDSCs can obviously suppress the electron recombinations, increase the electron lifetime and result in smoother electron transmission. In summary, the best conversion efficiency of QDSCs with POM/TiO2 electronic interface layers are increased to 8.02%, which are improved by 25.1% compared to the QDSCs without POM/TiO2. This work firstly builds an electron transfer bridge between FTO and quantum dot sensitizer and paves the way for the further efficiency improvement of QDSCs.
      PubDate: 2017-05-23T06:21:17.858876-05:
      DOI: 10.1002/cssc.201700764
       
  • Amphoteric ion-exchange membranes with significantly improved vanadium
           barrier properties for all-vanadium redox flow batteries.
    • Authors: Olga Nibel; Tomasz Rojek, Thomas J. Schmidt, Lorenz Gubler
      Abstract: All-vanadium redox flow batteries (VRBs) have attracted considerable interest as promising energy storage devices which can allow the efficient utilization of renewable energy sources. The membrane, which separates the porous electrodes in a redox flow cell, is one of the key components in VRBs. High rates of cross-over of vanadium ions and water through the membrane impair the efficiency and capacity of a VRB. Thus, membranes with low permeation rate of vanadium species and water are required, also characterized by low resistance and stability in the VRB environment. Here, we present a new design concept for amphoteric ion exchange membranes, based on radiation-induced grafting of vinylpyridine into an ethylene-tetrafluoroethylene base film and a two-step functionalization to introduce cationic and anionic exchange sites, respectively. During long-term cycling, redox flow cells containing these membranes showed higher efficiency, less pronounced electrolyte imbalance and significantly reduced capacity decay compared to the cells with the benchmark material Nafion® 117 and 212.
      PubDate: 2017-05-23T04:20:22.556256-05:
      DOI: 10.1002/cssc.201700610
       
  • A robust, water-based, functional binder framework for high energy
           lithium-sulfur batteries
    • Authors: Matthew James Lacey; Viking Österlund, Fabian Jeschull, Andreas Bergfelt, Tim Bowden, Daniel Brandell
      Abstract: We report here a water-based functional binder framework for the lithium-sulfur battery system, based on the general combination of a polyether and an amide-containing polymer. These binders are applied here to positive electrodes optimised towards high energy electrochemical performance based only on commercially available materials. Electrodes with up to 4 mAh cm-2 capacity and 97 - 98% coulombic efficiency are achievable in electrodes with a 65% total sulfur content and a poly(ethylene oxide):poly(vinylpyrrolidone) (PEO:PVP) binder system. Exchange of either binder component for a different polymer with similar functionality preserves the high capacity and coulombic efficiency. The improvement in coulombic efficiency from the inclusion of the coordinating amide group was also observed in electrodes where pyrrolidone moieties were covalently grafted to the carbon black, indicating the role of this functionality in facilitating polysulfide adsorption to the electrode surface. Mechanical properties of the electrodes appear not to significantly influence sulfur utilisation or coulombic efficiency in the short term but rather determine retention of these properties over extended cycling. These results demonstrate the robustness of this very straightforward approach, as well as the considerable scope for designing binder materials with targeted properties.
      PubDate: 2017-05-19T08:01:25.060212-05:
      DOI: 10.1002/cssc.201700743
       
  • Asymmetric supercapacitors based on rGO-PMo12 as a positive and rGO-PW12
           as a negative electrode
    • Authors: Deepak Dubal; Nilesh Chodankar, Ajayan Vinu, Do-Heyoung Kim, Pedro Gomez-Romero
      Abstract: Nanofabrication via "bottom-up" approach of hybrid electrode materials into well-defined architecture is essential for the next generation miniaturized energy storage devices. This paper describes the design and fabrication of reduced graphene oxide (rGO)/polyoxometalates (POMs) based hybrid electrode materials and their successful exploitation for asymmetric supercapacitor. Firstly, the redox active nanoclusters of POMs (phosphomolybdic acid (PMo12) and phosphotungstic acid (PW12)) are uniformly decorated on the surface of rGO nanosheets to take full advantage of both charge-storing mechanisms (faradaic from POMs and electric double layer from rGO). The as-synthesized rGO-PMo12 and rGO-PW12 hybrid electrodes exhibits great electrochemical performances with specific capacitance of 299 F/g (269 mF/cm2) and 370 F/g (369 mF/cm2) in 1 M H2SO4 electrolyte at 5 mA/cm2, respectively. Later, asymmetric supercapacitors was fabricated using rGO-PMo12 as a positive and rGO-PW12 as negative electrodes. This novel rGO-PMo12//rGO-PW12 asymmetric cell could be successfully cycled in a wide voltage window up to 1.6 V and hence exhibits excellent energy density of 39 Wh/kg (1.3 mWh/cm3) at a power density of 658 W/kg (23 mW/cm3).
      PubDate: 2017-05-18T23:06:59.585373-05:
      DOI: 10.1002/cssc.201700792
       
  • Organocatalytic Chemoselective Primary Alcohol Oxidation and Subsequent
           Cleavage of Lignin Model Compounds and Lignin
    • Authors: Saumya Dabral; Jose Hernández, Paul Kamer, Carsten Bolm
      Abstract: A one-pot two-step degradation of lignin β-O-4 model compounds initiated by preferred oxidation of the primary over the secondary hydroxyl groups with a TEMPO/DAIB system has been developed. The oxidised products are then cleaved by proline-catalysed retro-aldol reactions. This degradation methodology produces simple aromatics in good yields from lignin model compounds at room temperature with an extension to organosolv beechwood lignin L1 resulting in known cleavage products.
      PubDate: 2017-05-18T20:50:23.18525-05:0
      DOI: 10.1002/cssc.201700703
       
  • Environmentally friendly recycling of fuel cell's membrane electrode
           assembly using ionic liquids
    • Authors: Sophie Legeai; Maxime Balva, Nathalie Leclerc, Emmanuel Billy, Eric Meux
      Abstract: The platinum nanoparticles used as catalyst in Proton Exchange Membrane Fuel Cells (PEMFCs) could represent around 46 % of the total price of the cells1 for a large scale production which is one of the limitation of their commercialization. The recycling of this platinum catalyst can then be the best alternative to limit the production cost of PEMFCs. Usual recovery routes for spent catalysts containing platinum are pyro-hydrometallurgical processes in which a calcination step is followed by aqua regia treatment, generating fumes and NOx emission, respectively. An electrochemical recovery route is proposed here, more environmentally friendly, performed in "soft" temperature conditions and without any gases emission. It consists in the coupling of electrochemical leaching of platinum in chloride-based ionic liquids (ILs), followed by its electrodeposition. The leaching of platinum was studied in pure ionic liquids and in ionic liquids melts, at different temperatures and chloride contents. By modulating the composition of the ionic liquid melts, it is further possible to leach and electrodeposit the platinum from fuel cell electrodes in a single cell process, under inert or ambient atmosphere.
      PubDate: 2017-05-18T08:45:24.63433-05:0
      DOI: 10.1002/cssc.201700456
       
  • Dopant-Free Hole Transport Materials based on Methoxytriphenylamine
           Substituted Indacenodithienothiophene for Solution Processed Perovskite
           Solar Cells
    • Authors: Xiaoyuan Liu; Xiaolu Zheng, Yulong Wang, Zhiliang Chen, Fang Yao, Qi Zhang, Guojia Fang, Zhi-Kuan Chen, Wei Huang, ZongXiang Xu
      Abstract: Solution-processed hole transporting materials (HTMs) that are dopant-free show promise for use in low-cost, high performance perovskite solar cells (PSCs). The highest efficiency PSCs use organic HTMs, many of which have low mobilities and so require doping, which lowers the device stability. Additionally, these materials are not easily scaled because they often require complicated synthesis. Two novel HTMs (IDT-TPA and IDTT-TPA) were synthesized, which contained either an extended fused-ring indacenodithiophene (IDT) or indacenodithienothiophene (IDTT) core and strong electron donating methoxytriphenylamine (TPA) groups as the end-capping units. The extended conjugation in the backbone of IDTT-TPA resulted in stronger π-π interactions (3.321 Å) and a higher hole mobility of 6.46 × 10−4 cm2 V−1 s−1 when compared with that of IDT-TPA (9.53 × 10−5 cm2 V−1 s−1). A dopant free, planar PSC that contained IDTT-TPA was fabricated and exhibited a high power conversion efficiency (PCE) of 15.7%. This cell exhibited a higher PCE and less hysteresis than devices that contained IDT-TPA.
      PubDate: 2017-05-18T05:35:35.627593-05:
      DOI: 10.1002/cssc.201700197
       
  • Towards Long-Term Stable and Efficient Large-Area Organic Solar Cells
    • Authors: Pei-Ting Tsai; Kuan-Chu Lin, Cheng-Yu Wu, Chung-Hung Liao, Man-Chun Lin, Ying Qian Wong, Hsin-Fei Meng, Chih-Yu Chang, Chien-Lung Wang, Yi-Fan Huang, Sheng-Fu Horng, Hsiao-Wen Zan, Yu-Chiang Chao
      Abstract: In this study, we report that long-term stable and efficient organic solar cells (OSCs) can be obtained via the following strategies: (1) combination of rapid-drying blade-coating deposition with an appropriate thermal annealing treatment to obtain an optimized morphology of the active layer; (2) insertion of interfacial layers to optimize the interfacial properties. The resulting devices based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PBDTTT-EFT):[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) blend as the active layer exhibits a power conversion efficiency (PCE) up to 9.57%, which represents the highest efficiency ever reported for blade-coated OSCs. Importantly, the conventional structure devices based on poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blend can retain ~65% of their initial PCE for almost 2 years under operating conditions, which is the best result ever reported for long-term stable OSCs under operational conditions. More encouragingly, long-term stable large-area OSCs (active area = 216 cm2) based on P3HT:PCBM blend are also demonstrated. Our findings represent an important step toward the development of large-area OSCs with high performance and long-term stability.
      PubDate: 2017-05-17T22:00:32.688697-05:
      DOI: 10.1002/cssc.201700601
       
  • Reactive Precipitation of Anhydrous Alkali Sulfide Nanocrystals with
           Concomitant Abatement of Hydrogen Sulfide and co-Generation of Hydrogen
    • Authors: Yongan Yang; Xuemin Li, Yangzhi Zhao, Alice Brennan, Miranda McCeig, Colin A. Wolden
      Abstract: Anhydrous alkali sulfide (M2S, M = Li and Na) nanocrystals (NCs) are important materials central to the development of next generation cathodes and solid state electrolytes for advanced batteries, but not commercially available at present. This work reports an innovative method to directly synthesize M2S-NCs through alcohol-mediated reactions between alkali metals and hydrogen sulfide (H2S). In the first step, the alkali metal is complexed with alcohol in solution, forming metal alkoxide (ROM) and releasing hydrogen (H2). Next, H2S is bubbled through the ROM solution, where both chemicals are completely consumed to produce phase-pure M2S-NC precipitates and regenerate alcohol that can be recycled. The M2S-NC morphology may be tuned through choice of the alcohol and the solvent. Both synthetic steps are thermodynamically favorable (∆Gmo < -100 kJ/mol), proceeding rapidly to completion at ambient temperature with ~100% atom efficiency. The net result, H2S + 2M -> M2S + H2, makes good use of a hazardous chemical H2S and delivers two value-added products that naturally phase separate for easy recovery. This scalable approach provides an energy-efficient and environmentally-benign solution to the production of nanostructured materials required in emerging battery technologies.
      PubDate: 2017-05-16T10:45:29.314435-05:
      DOI: 10.1002/cssc.201700532
       
  • Nature-inspired Synthesis of Nanostructured Electrocatalysts through
           Mineralization of Calcium Carbonate
    • Authors: Jong Wan Ko; Eun Jin Son, Chan Beum Park
      Abstract: Biomineralization is a biogenic process that produces elaborate inorganic and organic hybrid materials in nature. Inspired by the natural process, this study explores novel mineralization approach to create nanostructured CaCO3 films composed of amorphous CaCO3 hemispheres using catechol-rich polydopamine (PDA) as a biomimetic mediator. We successfully transformed thus-synthesized biomimetic CaCO3 to nanostructured films of metal oxide minerals, such as FeOOH, CoCO3, NiCO3, and MnOOH, via a simple procedure. CaCO3-templated metal oxide minerals functioned as an efficient electrocatalyst; CaCO3-templated CoPi (nanoCoPi) film exhibited high stability as a water oxidation electrocatalyst with a current density of 1.5 mA cm-2. The nanostructure of nanoCoPi consisting of individual nanoparticles (~70 nm) and numerous internal pores (BET surface area: 3.17 m2g-1) facilitated an additional charge transfer pathway from the electrode to individual active sites of catalysts. This work demonstrates a plausible strategy for facile and green synthesis of nanostructured electrocatalysts through biomimetic CaCO3 mineralization.
      PubDate: 2017-05-10T23:55:24.544407-05:
      DOI: 10.1002/cssc.201700616
       
  • Highly efficient and uniform 1 cm² perovskite solar cells with an
           electrochemically deposited NiOx hole-extraction layer
    • Authors: Ik Jae Park; Gyeongho Kang, Min Ah Park, Ju Seong Kim, Se Won Seo, Dong Hoe Kim, Kai Zhu, Taiho Park, Jin Young Kim
      Abstract: Given that the highest certified conversion efficiency of the organic-inorganic perovskite solar cell (PSC) is already over 22%, which is even higher than that of the polycrystalline silicon solar cell, the significance of new scalable processes that can be utilized for preparing large-area devices and their commercialization is rapidly increasing. From this perspective, the electrodeposition method is one of the mostly suitable processes for preparing large-area devices, because it is an already commercialized process with proven controllability and scalability. Here, we report highly uniform NiOx layer prepared by the electrochemical deposition process as an efficient hole-extraction layer of a p-i-n type planar PSC with a large active area of> 1 cm². We demonstrate that the increased surface roughness of the NiOx layer, achieved by controlling the deposition current density, facilitates the hole extraction at the interface between perovskite and NiOx, and thus increases the fill factor and the conversion efficiency. The electrochemically deposited NiOx layer also exhibits extremely uniform thickness and morphology, leading to the highly efficient and uniform large-area PSCs. As a result, the p-i-n type planar PSC with an area of 1.084 cm² exhibits a stable conversion efficiency of 17.0% (19.2% for 0.1 cm²) without showing hysteresis effect.
      PubDate: 2017-05-10T09:55:24.382115-05:
      DOI: 10.1002/cssc.201700612
       
  • Alcoholysis: A Promising Technology for Conversion of Lignocellulose and
           Platform Chemicals
    • Authors: Shanhui Zhu; Jing Guo, Xun Wang, Jianguo Wang, Weibin Fan
      Abstract: In the catalytic conversion of lignocellulose to valuable products, the first entry point is to break down these biopolymers to sugar units or aromatic monomers, which is conventionally achieved by hydrolysis in water medium. Recent years have seen tremendous progress in alcoholysis process that possesses remarkable advantages such as the avoidance of treating waste water, suppression of humins or chars as well as increase of reaction rate and product yield. Here, the advances have been focused on the alcoholysis of cellulose, hemicellulose and lignin to alkyl glucosides, xylosides and aromatic monomers, respectively. We also summarize the alcoholysis of platform molecule furfuryl alcohol (FAL) to alkyl levulinate (AL) and integrated alcoholysis of cellulose and furfural into AL. This review highlights the comparisons between alcoholysis and hydrolysis, alcoholysis mechanism and future challenges for industrial applications.
      PubDate: 2017-05-09T03:24:13.615442-05:
      DOI: 10.1002/cssc.201700597
       
  • Carbon-Free O2 Cathode with Three-Dimensional Ultralight Nickel Foam
           Supported Ruthenium Electrocatalysts for Li-O2 Batteries
    • Authors: Ziqiang Liu; Ningning Feng, Zihan Shen, Fujun Li, Ping He, Huigang Zhang, Haoshen Zhou
      Abstract: Rechargeable Li-O2 batteries have received substantial attentions because of their high theoretical energy density. However, traditional carbon and binder-containing cathodes suffer from scientific and technical challenges for practical applications, such as high polarization and poor cycle life. We present a carbon and binder-free monolithic O2 cathode with Ru nanoparticle-coated on an ultralight nickel foam. This ultralight and monolithic structure leads to an ~300 times higher capacity than conventional carbon-free metal O2 cathode. The all metal structure enhances the electron transport and suppresses the CO2 evolution, which is the key factor of capacity fade of carbon-based Li-O2 batteries. The ultralight electrode structure has large surface/volume ratio and significantly lowers the mass of inactive components, which is important for a practical application.
      PubDate: 2017-05-08T11:20:26.928671-05:
      DOI: 10.1002/cssc.201700567
       
  • Gliding Arc Plasmatron: providing an alternative method for carbon dioxide
           conversion
    • Authors: Marleen Ramakers; Georgi Trenchev, Stijn Heijkers, Weizong Wang, Annemie Bogaerts
      Abstract: Low temperature plasmas are gaining a lot of interest forenvironmental and energy applications. A large research field in these applications is the conversion of CO2 into chemicals and fuels. Since CO2 is a very stable molecule, a key performance indicator for the research on plasma-based CO2 conversion is the energy efficiency. Until now, the energy efficiency in atmospheric plasma reactors is quite low, and therefore we employ here a novel type ofplasma reactor, the Gliding Arc Plasmatron (GAP). This paper provides a detailed experimental and computational study of the CO2 conversion, as well as the energy cost and efficiency in a GAP. A comparison with thermal conversion, other plasma types and other novel CO2 conversion technologies is made to find out whether thisnovel plasma reactor can provide a significant contribution to the much-needed efficient conversion of CO2. From these comparisons it becomes evident that our results currently obtained are less than a factor two away from being cost competitive and already outperformseveral other novel technologies. Furthermore, we indicate how the performance of the GAP can still be improved by further exploiting its non-equilibrium character. Hence, it is clear that the GAP is very promising for CO2 conversion.
      PubDate: 2017-05-08T06:20:28.411982-05:
      DOI: 10.1002/cssc.201700589
       
  • Non-conjugated polymer as an Efficient Dopant-Free Hole-Transporting
           Material for Perovskite Solar Cells
    • Authors: Yachao Xu; Tongle Bu, Meijin Li, Tianshi Qin, Chengrong Yin, Nana Wang, Renzhi Li, Jie Zhong, Fuzhi Huang, Hai Li, Yong Peng, Jianpu Wang, Linghai Xie, Wei Huang
      Abstract: A novel non-conjugated polymer (PVCz-OMeDAD) with good solution processability was developed to serve as an efficient dopant-free hole transporting material (HTM) for perovskite solar cells (PSCs). PVCz-OMeDAD was simply prepared by the free-radical polymerization of vinyl monomer which was synthesized from low cost raw materials via three high-yield synthesis steps. The combination of flexible non-conjugated polyvinyl main chain and hole-transporting methoxydiphenylamine-substituted carbazole side chain endowed PVCz-OMeDAD with excellent film-forming ability, suitable energy level, high hole mobility and low interfacial charge recombination. As a result, by using a ultra-thin (30 nm) PVCz-OMeDAD film as cost-effective dopant-free polymer HTM, the conventional n-i-p structure PSCs demonstrated a power conversion efficiency (PCE) up to 16.09%, suggesting its great potential for future low-cost large-scale flexible PSCs application
      PubDate: 2017-05-08T05:24:50.006857-05:
      DOI: 10.1002/cssc.201700584
       
  • High Photon-to-Current Conversion in Solar Cells based on Light Absorbing
           Silver-Bismuth-Iodide with Space Group R¯3m Crystal Structure
    • Authors: Huimin Zhu; Mingao Pan, Malin B. Johansson, Erik Johansson
      Abstract: In this report a lead-free silver-bismuth-iodide (AgI:BiI3) with a crystal structure with space group R3m is investigated for use in solar cells. Devices based on the silver-bismuth-iodide deposited from solution on top of TiO2, and the conducting polymer P3HT as a hole transport layer, are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2 %, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45 %. The results are compared to solar cells based on the previously reported material AgBi2I7, and we observe a clearly higher performance for the devices with the new silver-bismuth-iodide composition and different crystal structure. The XRD spectrum of the most efficient silver-bismuth-iodide material shows a hexagonal crystal structure with space group R3m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells.
      PubDate: 2017-05-08T05:24:41.878992-05:
      DOI: 10.1002/cssc.201700634
       
  • Coatable Li4SnS4 solid electrolytes prepared from aqueous solutions for
           all-solid-state lithium-ion batteries
    • Authors: Young Eun Choi; Kern Ho Park, Dong Hyeon Kim, Dae Yang Oh, Hi Ram Kwak, Young-Gi Lee, Yoon Seok Jung
      Abstract: Bulk-type all-solid-state lithium-ion batteries (ASLBs) for large-scale energy storage applications have emerged as a promising alternative to conventional lithium-ion batteries (LIBs) owing to their superior safety. However, the electrochemical performance of bulk-type ASLBs is critically limited by the low ionic conductivity of solid electrolytes (SEs) and poor ionic contact between the active materials and SEs. Herein, we report the highly conductive (0.14 mS cm-1) and dry-air-stable SEs, Li4SnS4, which are prepared using a scalable aqueous-solution process. An active material (LiCoO2) coated by solidified Li4SnS4 from aqueous solutions results in a significant improvement in the electrochemical performance of ASLBs. Side effect by the exposure of LiCoO2 to aqueous solutions is minimized by using predissolved Li4SnS4 solution.
      PubDate: 2017-05-08T03:23:09.496964-05:
      DOI: 10.1002/cssc.201700409
       
  • Enhancing the Acylation Activity of Acetic Acid by Forming an Intermediate
           Aromatic Ester
    • Authors: Nhung Duong; Bin Wang, Tawan Sooknoi, Steven P. Crossley, Daniel E. Resasco
      Abstract: Acylation is an effective C-C bond forming reaction to condense acetic acid and lignin-derived aromatic compounds into acetophenones, valuable precursors to fuels and chemicals. However, acetic acid is intrinsically an ineffective acylating agent. Here, we report that its acylation activity can be greatly enhanced by forming intermediate aromatic esters, directly derived from acetic acid and phenolics. Additionally, the acylation reaction was studied in the liquid phase over acid zeolites and was found to happen in two steps, (1) formation of an acylium ion and (2) C-C bond formation between acylium ion and the aromatic substrate. Each one of these steps can be rate-limiting, depending on the type of acylating agent and aromatic substrate. The O-containing substituents such as -OH and -OCH3 can activate aromatic substrates for step (2), with -OH> -OCH3, while alkyl substituent -R cannot. At the same time, the aromatic esters can rearrange to acetophenones via both an intramolecular pathway and, preferentially, an intermolecular one.
      PubDate: 2017-05-07T21:23:12.827648-05:
      DOI: 10.1002/cssc.201700394
       
  • Freestanding Gold/Graphene-Oxide/MnO2 Microsupercapacitor Displaying High
           Areal Energy Density
    • Authors: ahiud morag; james becker, Raz Jelinek
      Abstract: Microsupercapacitors are touted as one of the promising "next frontiers" in energy storage research and applications. Despite their potential, significant challenges still exist in term of physical properties and electrochemical performance, particularly attaining high energy density, stability, ease of synthesis, and feasibility of large-scale production. We present new freestanding microporous electrodes comprising self-assembled scaffold of gold and reduced graphene oxide (rGO) nanowires coated with MnO2. The electrodes exhibited excellent electrochemical characteristics, particularly superior high areal capacitance. Importantly, the freestanding Au/rGO scaffold also served as the current collector, obviating the need for an additional electrode support required in most reported supercapacitors, thus enabling low volume and weight devices with a high overall device specific energy. Stacked symmetrical solid-state supercapacitors were fabricated using the Au/rGO/MnO2 electrodes in parallel configurations showing the advantage of using freestanding electrodes in the fabrication of low volume devices.
      PubDate: 2017-05-05T05:23:37.694183-05:
      DOI: 10.1002/cssc.201700500
       
  • Sustainable gel electrolyte containing pyrazole as corrosion inhibitor and
           dendrite suppressor for aqueous Zn/LiMn2O4 battery
    • Authors: Tuan Hoang; The Nam Long Doan, Julie Hyeonjoo Cho, Jane Ying Jun Su, Christine Lee, Changyu Lu, Pu Chen
      Abstract: The Zn anode in secondary aqueous batteries suffers from dendrite formation and corrosion. In this work, the dendrite is suppressed by using a simple but novel gel electrolyte containing fumed silica and an additive. The dendrite suppression is evidenced by chronoamprometry and ex-situ scanning electron microscopy examinations. Pyrazole as the additive in the electrolyte has been implemented. It is found that the presence of 0.2 wt% of pyrazole in the electrolyte helps minimize both corrosion and dendrite formation. The Zn/LiMn2O4 battery using pyrazole containing gel electrolytes exhibits high cyclability, up to 85% capacity retention after 500 charge-discharge cycles at 4C. This is 8% higher than the performance of the reference battery (using aqueous electrolyte containing 2M Li2SO4 and 1M ZnSO4). Furthermore, self-discharge of the battery with the pyrazole-containing gel electrolyte is suppressed, evidenced by open-circuit voltage loss of 20% smaller, compared to the performance of the reference battery, after 24-hour monitoring. Float charge current density under constant voltage 2.1V also significantly decreases, from about 8.0 µA to 3-6 µA.
      PubDate: 2017-05-04T13:20:42.643281-05:
      DOI: 10.1002/cssc.201700441
       
  • Electrochemically-driven fermentation of organic substrates with undefined
           mixed microbial cultures
    • Authors: Marianna Villano; Paola Paiano, Enza Palma, Alfredo Miccheli, Mauro Majone
      Abstract: Growing scientific interest in mixed microbial culture-based anaerobic biotechnologies for the production of value-added chemicals and fuels from waste organic residues requires a parallel focus on the development and implementation of strategies to control products distribution. This study examined the feasibility of an electro-fermentation approach, based on the introduction of a polarized (-700 mV vs. the standard hydrogen electrode) graphite electrode in the fermentation medium, to steer products distribution during the conversion of organic substrates (glucose, ethanol, and acetate supplied as single compounds or in mixtures) by undefined mixed microbial cultures. As a main result, in batch experiments the polarized electrode triggered a nearly 20-fold increase (relative to open circuit controls) in the yield of i-butyrate production (0.43±0.01 vs. 0.02±0.02 mol/ mol glucose) during the anaerobic fermentation of the ternary mixture of substrates, without adversely affecting the rate of substrate bioconversion. The observed change in the fermentative metabolism was most likely triggered by the (potentiostatic) regulation of the oxidation-reduction potential of the reaction medium rather than by the electrode serving as an electron donor.
      PubDate: 2017-05-04T07:15:37.59715-05:0
      DOI: 10.1002/cssc.201700360
       
  • Polybenzoxazine-derived Nitrogen-Doped Carbon as Matrix for Powder-based
           Electrocatalysts
    • Authors: Stefan Barwe; Corina Andronescu, Justus Masa, Edgar Ventosa, Stefan Klink, Aziz Genç, Jordi Arbiol, Wolfgang Schuhmann
      Abstract: Besides catalytic activity, intrinsic stability, tight immobili¬sation on a suitable electrode surface and sufficient electronic con¬ductivity are fundamental prerequisites for the long-term operation of particle and especially powder-based electrocatalysts. We present a novel approach to concurrently address these challenges by using the unique properties of polxbenzoxazine (pBO) polymers, namely near-zero shrinkage and high residual char yield even after pyrolysis at high temperatures. Pyrolysis of a nanocubic Prussian blue analogue KmMnx[Co(CN)6]y x nH2O precursor embedded in a bisphenol A and aniline based pBO led to the formation of a N-doped carbon matrix modified with MnxCoyOz nanocubes. The obtained electrocatalyst exhibits high efficiency towards the oxygen evolution reaction (OER) and more importantly a stable performance for at least 65 h.
      PubDate: 2017-05-02T21:20:27.640715-05:
      DOI: 10.1002/cssc.201700593
       
  • New insights into the reactivity of biomass with butenes for the synthesis
           of butyl levulinates
    • Authors: Alexandre Démolis; Marion Eternot, Nadine Essayem, Franck Rataboul
      Abstract: This article reports a detailed study on the reactivity of levulinic acid and cellulose with 1-butene and iso-butene for the catalytic formation of sec- and tert-butyl levulinates. The influence of catalyst type and various solvent conditions has been particularly investigated to assess the potential of sustainable transformation. For instance we found a very simple and efficient procedure using reusable Amberlyst-15 in the absence of solvent to form, from levulinic acid and iso-butene, tert-butyl levulinate (70% yield) a compound very difficult to prepare by other means. sec-Butyl levulinate (66% yield) was obtained using Amberlyst-15 in gamma-butyrolactone as biosourced solvent. We also notably extended the original procedure using directly cellulose as reactant. In the presence of a catalytic amount of sulfuric acid, it was possible to form sec-butyl levulinate (19% yield) from 1-butene in a more efficient way than using the alcohol as esterifying agent.
      PubDate: 2017-05-02T11:02:45.931078-05:
      DOI: 10.1002/cssc.201700416
       
  • Polyimidazolium Salts: Robust Catalysts for the Cycloaddition of Carbon
           Dioxide into Carbonates that Operate at Atmospheric Pres-sure Under
           Solvent-Free Conditions
    • Authors: Felix Daniel Bobbink; Wei Zhong, Zhaofu Fei, Paul J. Dyson
      Abstract: There is growing interest in sustainable heterogeneous catalysts based on organic polymers. Here, we describe a series of polyimidazolium salt catalysts, prepared from the direct reaction of arene-bridged bis- and tris-alkyl halides with trimethylsilylimidazole. The polyimidazolium salts were characterized by spectroscopic and analytical techniques and it was found that their morphology and porosity could be controlled by adjusting the steric parameters of the spacer in the alkyl-halide starting materials. Moreover, the polymers are excellent heterogeneous organocatalysts for the cycloaddition of CO2 to epoxides to afford cyclic carbonates at atmospheric pressure under solvent-free conditions. The polymer catalysts exhibit long-term stability and may be recycled and reused at least 10 times.
      PubDate: 2017-05-02T10:49:00.452948-05:
      DOI: 10.1002/cssc.201700570
       
  • Ultra-Thin Alginate Coatings as Selective Layers for Nanofiltration
           Membranes with High Performance
    • Authors: Yong Du; Chao Zhang, Qi-Zhi Zhong, Xi Yang, Jian Wu, Zhi-Kang Xu
      Abstract: It is highly desirable to develop environmental friendly processes for fabricating thin film composite (TFC) nanofiltration membranes (NFMs) from natural materials. However, nanofiltration performance of such TFC NFMs is not satisfactory for practical applications due to the lack of efficient methods for constructing those ultra-thin, uniform and stable coatings as the selective layers. Here we demonstrate a contra-diffusion strategy for fabricating TFC NFMs with ultra-thin crosslinked alginate coatings as the selective layers without any organic solvent involved. The as-prepared NFMs show nearly one order of magnitude higher water permeation flux than other alginate-based TFC NFMs with similar salt rejection, representing the best performance among all TFC NFMs from natural materials. These NFMs also possess excellent mono-/divalent ion selectivity, along with good long-term operation stability and antifouling property. Furthermore, our strategy has the maximized reactant usage rate and the minimized waste discharge, which provides new insight into the environmental friendly fabrication of TFC NFMs.
      PubDate: 2017-05-02T09:54:51.324744-05:
      DOI: 10.1002/cssc.201700519
       
  • Engineering Pores of Biomass-Derived Carbon: Insights for Achieving
           Ultra-high Stability at High Power in High-Energy Supercapacitors
    • Authors: Yun-Sung Lee; Ranjith Thangavel, Karthikeyan Kaliyappan, Hari Vignesh Ramasamy, Xueliang Sun
      Abstract: Electrochemical supercapacitors possessing a high energy density are promising devices due to their simple construction and long-term cycling performance. Developing a supercapacitor based on electrical double layer charge storage with high energy density while preserving its cyclability at higher power presents an ongoing challenge. We hereby provide the insights for achieving a high energy density at high power with an ultra-high stability in Electrical Double Layer Capacitor (EDLC) system utilizing carbon from a biomass—cinnamon sticks in a sodium ion organic electrolyte. We have deeply investigated the dependence of EDLC performance on structural, textural, & functional properties of porous carbon engineered by various activation agents. The results demonstrate that the performance of EDLCs not dependent on their textural properties, but on their structural features & surface functionalities, which is evident from electrochemical studies. The results are highly promising, that porous carbon with poor textural properties has great potential to deliver high capacitance & outstanding stability of 300,000 cycles, than the carbon with good textural properties. An ultra-low capacitance degradation of ~0.066% per 1000 cycles along with high energy (~70 Wh kg-1) and high power have been achieved, emerging as a high energy supercapacitor. The results open a new platform for application of low-surface area biomass carbons in establishing highly stable high-energy supercapacitors.
      PubDate: 2017-04-28T09:29:43.320755-05:
      DOI: 10.1002/cssc.201700492
       
  • Effect of Donor Strength and Bulk on Thieno[3,4 b]pyrazine based
           Panchromatic Dyes in DSCs
    • Authors: Nalaka P. Liyanage; Hammad Cheema, Alexandra R. Baumann, Alexa R. Zylstra, Jared Heath Delcamp
      Abstract: NIR absorbing organic dyes are critically needed in dye-sensitized solar cells (DSCs). Thieno[3,4-b]pyrazine (TPz) based dyes can access the near-infrared (NIR) spectral region and show power conversion efficiencies (PCEs) of up to 8.1% with sunlight being converted at wavelengths up to 800 nm for 17.6 mA/cm2 of photocurrent in a co-sensitized DSC device. Precisely controlling dye excited-state energies is critical for good performances in NIR DSCs. Strategies to control TPz dye energetics with stronger donor groups and TPz substituent choice are evaluated in this manuscript. Additionally, donor size influence versus dye loading on TPz dyes is analysed with respect to TiO2 surface protection designed to prevent recombination of electrons in TiO2 with the redox shuttle. Importantly, the dyes evaluated were demonstrated to work well with low Li+ concentration electrolytes, with iodine and cobalt redox shuttle systems, and efficiently as part of co-sensitized devices.
      PubDate: 2017-04-25T13:20:30.050329-05:
      DOI: 10.1002/cssc.201700546
       
  • Interconnected 3D Network of Carbon Dots decorated Reduced Graphene Oxide
           Nanosheets for High-Performance Supercapacitors
    • Authors: Mingtao Zheng; Xiao Zhao, Ming Li, Hanwu Dong, Yingliang Liu, Hang Hu, Yijin Cai, Yeru Liang, Yong Xiao
      Abstract: Interconnected 3D network of reduced graphene oxide decorated with carbon dots (rGO/CDs) nanosheets are successfully fabricated via a simple one-pot hydrothermal process. The as-prepared rGO/CDs present appropriate 3D interconnected structure and abundant oxygen-containing functional groups, which attribute to excellent electrochemical performance such as high specific capacitance, good rate capability, and great cycling stability. Employed as binder-free electrodes for supercapacitor, the as-resulted rGO/CDs exhibit excellent long-term cycling stability (ca. 92% capacitance retention after 20,000 charge/discharge cycles at current density of 10 A g-1) as well as a maximum specific capacitance of ca. 308 F g-1 at current density of 0.5 A g-1, which is much higher than that of rGO (200 F g-1) and individual CDs (2.2 F g-1). This work provides a promising strategy to fabricate graphene-based nanomaterials with greatly boosted electrochemical performances by decoration of rGO with CDs.
      PubDate: 2017-04-24T22:20:32.978364-05:
      DOI: 10.1002/cssc.201700474
       
  • Ehanced Solar Water Splitting by Swift Charge Separation in Au/FeOOH
           Sandwiched Single Crystalline Fe2O3 Nanoflake Photoelectrodes
    • Authors: Lei Wang; Nhat Truong Nguyen, Yajun Zhang, Yingpu Bi, Patrik Schmuki
      Abstract: In this work, single crystalline α-Fe2O3 nanoflakes (NFs) are formed in a highly dense array by Au seeding of a Fe substrate by a thermal oxidation technique. The NFs are conformally decorated with a thin FeOOH cocatalyst layer. Photoelectrochemical (PEC) measurements show that this photoanode with the α-Fe2O3/FeOOH NFs rooted on the Au/Fe structure exhibits a significantly enhanced PEC water oxidation performance compared to the plain α-Fe2O3 nanostructure on the Fe substrate. The α-Fe2O3/FeOOH NFs on Au/Fe photoanode yields a photocurrent density of 3.1 mA cm-2 at 1.5 VRHE, and a remarkably low onset potential of 0.5-0.6 VRHE in 1 M KOH under AM 1.5G (100 mW cm-2) simulated sunlight illumination. The enhancement in PEC performance can be attributed to a synergistic effect of the FeOOH top decoration and Au under-layer. While FeOOH facilitates hole transfer at the interface of electrode/electrolyte, the Au layer provides a sink for the electron transport to the back contact: this leads overall to a drastically improved charge-separation efficiency in the single crystalline α-Fe2O3 NF photoanode.
      PubDate: 2017-04-24T11:20:50.124317-05:
      DOI: 10.1002/cssc.201700522
       
  • Pectin, Hemicellulose or Lignin? Impact of the Biowaste Source on the
           Performance of Hard Carbons for Sodium ion Batteries
    • Authors: xinwei Dou; Ivana Hasa, Maral Hekmatfar, Thomas Diemant, R. Juergen Behm, Daniel Buchholz, Stefano Passerini
      Abstract: Hard carbons are currently the most widely used negative electrode materials in Na-ion batteries. This is due to their promising electrochemical performance with capacities of 200-300 mAh g-1 and stable long-term cycling. However, an abundant and cheap carbon source is necessary in order to comply with the low-cost philosophy of the Na-ion technology. As a matter of fact, many biologic or waste materials have been used to synthesize hard carbons but the impact of the precursors on the final properties of the anode material is not fully understood. In this study we unravel the impact of the biomass source on the structural and electrochemical properties of hard carbons, using different, representative types of biomass as examples. The systematic structural and electrochemical investigation of hard carbons derived from different sources, namely corncobs, peanut shells and waste apples, representatives of hemicellulose-, lignin- and pectin- rich biomass, respectively, enables to understand and interlink the structural and electrochemical properties.
      PubDate: 2017-04-20T04:32:29.795101-05:
      DOI: 10.1002/cssc.201700628
       
  • Green processing of lignocellulosic biomass and its derivatives in deep
           eutectic solvents
    • Authors: Xing Tang; Miao Zuo, Zheng Li, Huai Liu, Caixia Xiong, Xianhai Zeng, Yong Sun, Lei Hu, Tingzhou Lei, Shijie Liu, Lu Lin
      Abstract: The scientific community has been seeking cost-competitive and green solvents with good dissolving capacity for the valorization of lignocellulosic biomass. At this point, deep eutectic solvents (DESs) are currently emerging as a new class of promising solvents, which are generally liquid eutectic mixtures formed by self-association (or hydrogen-bonding interaction) of two or three components. DESs are attractive solvents for the fractionation (or pretreatment) of lignocellulose and the valorization of lignin, owing to the high solubility of lignin in DESs. DESs are also employed as effective media for the modification of cellulose to afford functionalized cellulosic materials like cellulose nanocrystals (CNCs). More interestingly, biomass-derived carbohydrates such as fructose can be used as one of the constituents of DESs and then dehydrated to 5-hydroxymethylfurfural (HMF) with high yields. In this review, we comprehensively summarize the recent contribution of DESs to the processing of lignocellulosic biomass and its derivatives. Moreover, further discussion about the challenges of the application of DESs in biomass processing is represented.
      PubDate: 2017-04-20T00:30:54.694841-05:
      DOI: 10.1002/cssc.201700457
       
  • Controlled Growth of CH3NH3PbI3 using a Dynamically Dispensed Spin-Coating
           Method: Improving Efficiency with a Reproducible PbI2 Blocking Layer
    • Authors: Yingzhuang Ma; Parth Vashishtha, Kai Chen, Elijah Peach, David Ohayon, Justin Hodgkiss, Jonathan Halpert
      Abstract: It is commonly believed that excess PbI2 has beneficial effects for perovskite solar cells due to the modification of charge transport behavior at interfaces, by surface passivation and by blocking electron-hole recombination. Here, we introduce a dynamically dispensed spin coating technique in a two-step deposition to form a perovskite layer with controllable quantities of crystalline PbI2. Using this technique, the concentration of CH3NH3I solution is kept constant at the reaction interface, ensuring smooth growth of films. By changing the spinning rate during the reaction, the PbI2 conversion ratio and perovskite cuboid size can be optimized, resulting in a power conversion efficiency improvement over control devices. This dynamically dispensed technique represents a repeatable method for compositional control in perovskite solar cells and improves our understanding of how a PbI2 blocking layer improves the performance of perovskite solar cells.
      PubDate: 2017-04-19T00:22:14.172644-05:
      DOI: 10.1002/cssc.201700449
       
  • A reversed photosynthesis-like process for light-triggered CO2 capture,
           release and conversion
    • Authors: Yapei Wang; Dingguan Wang, Shenglong Liao, Shiming Zhang
      Abstract: Materials for CO2 capture have been extensively exploited for climate governance and gaseous separation. However, their regeneration is facing the problems of high energy cost and secondary CO2 contamination. Herein, a reversed photosynthesis-like process is proposed, which absorbs CO2 in darkness while releases CO2 under light illumination. The process is likely supplementary to natural photosynthesis of plants which on the contrary release CO2 in nights. Remarkably, the material used in this work is able to capture 9.6 wt.% CO2 according to its active component. Recyclable CO2 capture at room temperature and release under light irradiation ensure its convenient and cost-effective regeneration. Furthermore, CO2 released from the system is successfully converted into stable compound in tandem with specific catalysts.
      PubDate: 2017-04-16T23:15:27.806084-05:
      DOI: 10.1002/cssc.201700365
       
  • A blue diketopyrrolopyrrole sensitizer with high efficiency in NiO based
           dye-sensitized solar cells
    • Authors: Fabrice Odobel; Yoann Farre, Mahfoudh Raissi, Arnaud Fihey, Yann Pellegrin, Errol Blart, Denis Jacquemin
      Abstract: We have prepared a series of four new diketopyrrolopyrroles (DPPs) based sensitizers that exhibit high molar extinction coefficients, extended absorption into the long wavelengths and well suited photoredox properties to act as sensitizers in p-DSSCs. These new DPP dyes, composed of a thienyl DPP core, are substituted on one end either by a thiophene carboxylic (Th) or a 4,4'-((phenyl)aza)dibenzoic acid as anchoring group and, on the other extremity, either by a proton or a naphthalene diimide (NDI) moiety. These new dyes were completely characterized by absorption and emission spectroscopy along with electrochemistry and they were modeled by TD-DFT quantum chemical calculations. The photovoltaic study in p-DSSC with iodine based electrolyte reveals that the dye Th-DPP-NDI is particularly efficient (Jsc = 7.38 mA/cm2; Voc = 147 mV; ff = 0.32;  = 0.35%) and quite active in the low energy part of the solar spectrum (above 700 nm), where few NiO dyes are effective. To illustrate the potential of DPP dyes in photocathode, we have designed a highly efficient tandem DSSC composed of a TiO2 photoanode sensitized by the dye D35 and a NiO photocathode sensitized by Th-DPP-NDI. This tandem DSSC gives the highest performances ever reported (Jsc = 6.73 mA/cm2; Voc = 910 mV;  = 4.1%) and importantly the tandem cell outcompetes with each of the subs-cells.
      PubDate: 2017-04-14T05:25:21.308573-05:
      DOI: 10.1002/cssc.201700468
       
  • Process Intensification for Cellulosic Biorefineries
    • Authors: Sunitha Sadula; Abhay Athaley, Weiqing Zheng, Marianthi Ierapetritou, Basudeb Saha
      Abstract: Utilization of renewable carbon source, especially non-food biomass is critical to address the climate change and future energy challenge. Current chemical and enzymatic processes for producing cellulosic sugars are multistep, and energy- and water-intensive. Techno-economic analysis (TEA) suggests that upstream lignocellulose processing is a major hurdle to the economic viability of the cellulosic biorefineries. Process intensification, which integrates processes and uses less water and energy, has the potential to overcome the aforementioned challenges. Here, we demonstrate a one-pot depolymerization and saccharification process of woody biomass, energy crops, and agricultural residues to produce soluble sugars with high yields. Lignin is separated as a solid for selective upgrading. Further integration of our upstream process with a reactive extraction step makes energy-efficient separation of sugars in the form of furans. TEA reveals that the process efficiency and integration enable, for the first time, economic production of feed streams that could profoundly improve process economics for downstream cellulosic bioproducts.Sugar, furan, how you get so cheap? Process intensification is an improved strategy for sugars and furans production with high yields and selectivity from multiple non-food biomass with lower consumption of water and energy. Techno-economic analysis shows that the process efficiency and integration enable, for the first time, economic production of feed streams that could profoundly improve process economics for downstream cellulosic bioproducts.
      PubDate: 2017-04-13T10:00:24.09814-05:0
      DOI: 10.1002/cssc.201700183
       
  • Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for
           Efficient Continuous-Flow Nanocatalysis
    • Authors: Hirotaka Koga; Naoko Namba, Tsukasa Takahashi, Masaya Nogi, Yuta Nishina
      Abstract: Continuous-flow nanocatalysis by metal nanoparticle (NP) catalyst-anchored flow reactors has recently provided an excellent platform for effective chemical manufacturing. However, there has been limited progress in porous structure design and recycling systems for metal NP-anchored flow reactors to create more efficient and sustainable catalytic processes. Here, we renovated traditional paper as an efficient, recyclable, and renewable flow reactor by tailoring the ultra-structures of wood pulp. The 'paper reactor' offers hierarchically interconnected micro/nanoscale pores for efficient access of reactants to catalysts. In continuous-flow catalytic reduction of 4-nitrophenol, a gold NP-anchored paper reactor with the tailored micro/nanopores provided higher reaction efficiency than state-of-the-art flow reactors. Successful recycling and renewing of the paper reactors were also demonstrated. Our strategy offers potential for highly efficient and truly sustainable chemical manufacturing.
      PubDate: 2017-04-10T07:31:11.750831-05:
      DOI: 10.1002/cssc.201700576
       
  • Simple and Effective Catalyst Separation by Novel CO2-induced Switchable
           Organocatalysts
    • Authors: Julia Großeheilmann; Udo Kragl
      Abstract: CO2-induced switchable tertiary amine-based organocatalysts were investigated for an efficient catalyst and product separation by its different partitioning between an organic and carbonated water phase. In this case study, the switching ability of 8 tertiary amine-based catalysts between the organic and water phase by addition or removal of CO2 was investigated. Here, the catalyst switched both nearly completely (99.9%) into the aqueous phase by addition of CO2 and effectively back into the organic phase (99.3%) by expelling CO2. With this technique, the organocatalyst was successfully recovered and reused for twelve times without significant loss of activity (up to 90% ee) for the asymmetric nitroaldol (Henry) reaction. After the first catalyst switch, evaporation of the solvent affords the product in 98% purity without any further purification steps.
      PubDate: 2017-04-07T04:23:21.487216-05:
      DOI: 10.1002/cssc.201700491
       
  • Electrospinning Hetero-Nanofibers of Fe3C-Mo2C/Nitrogen-Doped-Carbon as
           Efficient Electrocatalysts for Hydrogen Evolution
    • Authors: Huanlei Lin; Wenbiao Zhang, Zhangping Shi, Minwei Che, Xiang Yu, Yi Tang, Qingsheng Gao
      Abstract: Heterostructured electrocatalysts with multiple active components are expected to synchronously address the two elementary steps in hydrogen evolution reactions (HER), which require varied hydrogen binding strength on catalyst surface. Herein, electrospinning followed by a pyrolysis is introduced to design Fe3C-Mo2C/nitrogen-doped carbon (Fe3C-Mo2C/NC) hetero-nanofibers (HNFs) with tuneable composition, accomplishing the abundant Fe3C-Mo2C hetero-interfaces for synergy in electrocatalysis. Thanks to the strong hydrogen binding on Mo2C and the relatively weak one on Fe3C, the hetero-interfaces of Fe3C-Mo2C remarkably promote HER kinetics and intrinsic activity. Meanwhile, the loose and porous N-doped carbon matrix, as a result of Fe-catalyzed carbonization, ensures the fast transport of electrolytes and electrons, minimizing the limitation by diffusion. As expected, the optimal Fe3C-Mo2C/NC HNFs afford a low overpotential of 116 mV at a current density of -10 mA cm-2 and striking kinetics metrics (onset overpotential: 42 mV, Tafel slope: 43 mV dec-1) in 0.5 M H2SO4, outperforming most of recently-reported noble-metal-free electrocatalysts.
      PubDate: 2017-03-30T06:20:42.487617-05:
      DOI: 10.1002/cssc.201700207
       
 
 
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