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  Subjects -> MATHEMATICS (Total: 968 journals)
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    - MATHEMATICS (714 journals)
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MATHEMATICS (714 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 4)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4)
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: 15)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Hybrid Journal   (Followers: 29)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 12)
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: 6)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 10)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 3)
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: 19)
Advances in Decision Sciences     Open Access   (Followers: 3)
Advances in Difference Equations     Open Access   (Followers: 3)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 3)
Advances in Materials Science     Open Access   (Followers: 14)
Advances in Mathematical Physics     Open Access   (Followers: 4)
Advances in Mathematics     Full-text available via subscription   (Followers: 11)
Advances in Numerical Analysis     Open Access   (Followers: 5)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Pure and Applied Mathematics     Hybrid Journal   (Followers: 6)
Advances in Pure Mathematics     Open Access   (Followers: 6)
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: 11)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Al-Jabar : Jurnal Pendidikan Matematika     Open Access   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 6)
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: 11)
Algorithms Research     Open Access   (Followers: 1)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 5)
American Journal of Mathematical Analysis     Open Access  
American Journal of Mathematics     Full-text available via subscription   (Followers: 6)
American Journal of Operations Research     Open Access   (Followers: 5)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 8)
Analele Universitatii Ovidius Constanta - Seria Matematica     Open Access   (Followers: 1)
Analysis and Applications     Hybrid Journal   (Followers: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 5)
Analysis Mathematica     Full-text available via subscription  
Analysis. International mathematical journal of analysis and its applications     Hybrid Journal   (Followers: 2)
Annales Mathematicae Silesianae     Open Access  
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica     Open Access  
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1)
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Data Science     Hybrid Journal   (Followers: 12)
Annals of Discrete Mathematics     Full-text available via subscription   (Followers: 6)
Annals of Mathematics     Full-text available via subscription   (Followers: 1)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12)
Annals of Pure and Applied Logic     Open Access   (Followers: 3)
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)
ANZIAM Journal     Open Access   (Followers: 1)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applications of Mathematics     Hybrid Journal   (Followers: 2)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 11)
Applied Mathematics     Open Access   (Followers: 3)
Applied Mathematics     Open Access   (Followers: 7)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 6)
Applied Mathematics - A Journal of Chinese Universities     Hybrid Journal  
Applied Mathematics Letters     Full-text available via subscription   (Followers: 2)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1)
Applied Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 3)
Arabian Journal of Mathematics     Open Access   (Followers: 2)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
Armenian Journal of Mathematics     Open Access  
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites     Open Access   (Followers: 20)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Journal of Algebra     Open Access   (Followers: 1)
Asian Journal of Current Engineering & Maths     Open Access  
Asian-European Journal of Mathematics     Hybrid Journal   (Followers: 2)
Australian Mathematics Teacher, The     Full-text available via subscription   (Followers: 6)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 4)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access   (Followers: 1)
Baltic International Yearbook of Cognition, Logic and Communication     Open Access   (Followers: 1)
Basin Research     Hybrid Journal   (Followers: 5)
BIBECHANA     Open Access   (Followers: 2)
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: 20)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 12)
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 Symbolic Logic     Full-text available via subscription   (Followers: 2)
Bulletin of the Australian Mathematical Society     Full-text available via subscription   (Followers: 1)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 4)
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: 19)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
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: 1)
Cogent Mathematics     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Collectanea Mathematica     Hybrid Journal  
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Combinatorics and Optimization     Open Access  
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 2)
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: 8)
Compositio Mathematica     Full-text available via subscription   (Followers: 1)
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: 5)
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: 8)
Concrete Operators     Open Access   (Followers: 5)
Confluentes Mathematici     Hybrid Journal  
Contributions to Game Theory and Management     Open Access  
COSMOS     Hybrid Journal  
Cryptography and Communications     Hybrid Journal   (Followers: 13)
Cuadernos de Investigación y Formación en Educación Matemática     Open Access  
Cubo. A Mathematical Journal     Open Access  
Current Research in Biostatistics     Open Access   (Followers: 9)
Czechoslovak Mathematical Journal     Hybrid Journal   (Followers: 1)
Demographic Research     Open Access   (Followers: 11)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 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: 3)
Differentsial'nye Uravneniya     Open Access  
Discrete Mathematics     Hybrid Journal   (Followers: 8)
Discrete Mathematics & Theoretical Computer Science     Open Access  
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae - General Algebra and Applications     Open Access  
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Diskretnaya Matematika     Full-text available via subscription  
Dnipropetrovsk University Mathematics Bulletin     Open Access  
Doklady Akademii Nauk     Open Access  
Doklady Mathematics     Hybrid Journal  
Duke Mathematical Journal     Full-text available via subscription   (Followers: 1)
Eco Matemático     Open Access  
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Electronic Journal of Combinatorics     Open Access  
Electronic Journal of Differential Equations     Open Access  
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: 4)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  

        1 2 3 4 | Last

Journal Cover
Chinese Journal of Catalysis
Journal Prestige (SJR): 0.833
Citation Impact (citeScore): 3
Number of Followers: 2  
 
  Full-text available via subscription Subscription journal
ISSN (Print) 1872-2067
Published by Elsevier Homepage  [3159 journals]
  • Elucidating the dominant reaction mechanism of methanol-to-olefins
           conversion in H-SAPO-18: A first-principles study
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Chuan-Ming Wang, Yang-Dong Wang, Zai-Ku Xie The reaction mechanism of zeolite- or zeotype-catalyzed methanol-to-olefins (MTO) conversion is still a subject of debate. Employing periodic density functional theory calculations, the olefin-based cycle was studied using tetramethylethene (TME) as a representative olefinic hydrocarbon pool in H-SAPO-18 zeotype. The overall free energy barrier at 673 K was calculated and found to be less than 150 kJ/mol in the TME-based cycle, much lower than those in the aromatic-based cycle (> 200 kJ/mol), indicating that olefins themselves are the dominant active hydrocarbon pool species in H-SAPO-18. The similarity of the intermediates involved between the aromatic-based cycle and the olefin-based cycle was also highlighted, revealing that both cycles were pattern-consistent. The selectivity related to the distribution of cracking precursors, such as higher olefins or carbenium ions, as a result of the olefin-based cycle for the MTO conversion. The enthalpy barrier of the cracking step scaled linearly with the number of carbon atoms of cracking precursors to produce ethene or propene with ethene being much less favored than propene for cracking of C7 and higher precursors. This work highlighted the importance of the olefin-based cycle in H-SAPO-18 for the MTO conversion and established the similarity between the olefin-based and aromatic-based cycles.Graphical The olefins were calculated to be the dominant hydrocarbon pool for MTO conversion in H-SAPO-18. The enthalpy barrier of the cracking step linearly relates to the size of cracking precursors.Graphical abstract for this article
       
  • Facile synthesis of Fe-containing graphitic carbon nitride materials and
           their catalytic application in direct hydroxylation of benzene to phenol
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Bing Xue, Ye Chen, Yin Hong, Ding-Yang Ma, Jie Xu, Yong-Xin Li Fe-containing graphitic carbon nitride (Fe-g-C3N4) materials were synthesized via one-step pyrolysis of FeCl3 and dicyandiamide. The physicochemical properties of the synthesized Fe-g-C3N4 samples were characterized by N2 adsorption-desorption, X-ray diffraction, thermal gravimetric, Fourier transform infrared, UV-vis diffuse reflectance, X-ray photoelectron spectroscopy, and transmission electron microscopy. The Fe cations were anchored by nitrogen-rich g-C3N4, whereas the graphitic structures of g-C3N4 were retained after the introduction of Fe. As heterogeneous catalysts, Fe-g-C3N4 exhibited good catalytic activity in the direct hydroxylation of benzene to phenol with H2O2, affording a maximum yield of phenol of up to 17.5%. Compared with other Fe- and V-containing g-C3N4 materials, Fe-g-C3N4 features a more convenient preparation procedure and higher catalytic productivity of phenol.Graphical Fe-containing graphitic carbon nitride materials were synthesized via one-step pyrolysis. Fe species are anchored and well dispersed on the g-C3N4 support, which showed superior catalytic activity in the catalytic hydroxylation of benzene to phenol.Graphical abstract for this article
       
  • Carboxylative Suzuki coupling reactions of benzyl chlorides with allyl
           pinacolborate catalyzed by palladium nanoparticles
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Jian Sun, Jiasheng Wang, Xiujuan Feng, Yoshinori Yamamoto, Abdulrahman I. Almansour, Natarajan Arumugam, Raju Suresh Kumar, Ming Bao Palladium-catalyzed carboxylative Suzuki coupling reactions of benzyl chlorides with allyl pinacolborate were successfully conducted in the absence of any extra ligand to produce β,γ-unsaturated esters in satisfactory to good yields. The carboxylative Suzuki coupling reaction proceeded smoothly under mild conditions in the presence of palladium nanoparticles generated in situ through the formation of a π-benzylpalladium chloride intermediate.Graphical A novel palladium nanoparticles-based catalyst system for carboxylative Suzuki coupling reactions of benzyl chlorides with allyl pinacolborate was developed under mild reaction conditions (low CO2 pressure and temperature) in the absence of any extra ligands. The catalytic system is generated in situ and can thus avoid cumbersome processes for the preparation of metal nanoparticles.Graphical abstract for this article
       
  • Superior performance of Co-N/m-C for direct oxidation of alcohols to
           esters under air
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Ning Li, Sensen Shang, Lianyue Wang, Jingyang Niu, Ying Lv, Shuang Gao A convenient, expeditious, and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material (Co-N/m-C) as the catalyst is proposed. The catalyst was prepared through direct pyrolysis of a macromolecular precursor. The catalyst prepared using a pyrolysis temperature of 900 °C (labeled Co-N/m-C-900) exhibited the best performance. The strong coordination between the ultra-dispersed cobalt species and the pyridine nitrogen as well as the large area of the mesoporous surface resulted in a high turnover frequency value (107.6 mol methyl benzoate mol−1 Co h−1) for the direct aerobic oxidation of benzyl alcohol to methyl benzoate. This value is much higher than those of state-of-the-art transition-metal-based nanocatalysts reported in the literature. Moreover, the catalyst exhibited general applicability to various structurally diverse alcohols, including benzylic, allylic, and heterocyclic alcohols, achieving the target esters in high yields. In addition, a preliminary evaluation revealed that Co-N/m-C-900 can be used six times without significant activity loss. In general, the process was rapid, simple, and cost-effective.Graphical We report an expeditious and eco-efficient methodology for the synthesis of esters by aerobic oxidative esterification of readily available alcohols using a cobalt-modified N-doped mesoporous carbon material (Co-N/m-C) as the catalyst under air atmosphere.Graphical abstract for this article
       
  • Facile synthesis of UCNPs/Zn x Cd1-x S nanocomposites excited by
           near-infrared light for photochemical reduction and removal of Cr(VI)
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Mengli Zhao, Wanni Wang, Chenxi Huang, Wang Dong, Yang Wang, Sheng Cheng, Huiqing Wang, Haisheng Qian Photocatalysis driven by near-infrared (NIR) light is of scientific and technological interest for exploiting solar energy. In this study, we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles (UCNPs) and alloyed ZnxCd1-xS, which can be excited using NIR or visible light. Morphologies, phase, and chemical composition have been investigated using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and atomic absorption spectroscopy. Moreover, we found that amorphous TiO2 layers existing in the final samples play an important role in formation of UCNPs@ZnxCd1-xS yolk-shell nanoparticles, which bind the as-prepared ZnxCd1-xS nanoparticles tightly to form yolk-shell nanoparticles. The chemical composition of alloyed ZnxCd1-xS can be tunable by adjusting the amount of the Cd and Zn source compounds. The photochemical reduction of Cr(VI) in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light, showing efficient photoreduction and Cr(VI) removal over the as-prepared UCNPs@ZnxCd1-xS/TiO2 yolk-shell nanoparticles. The as-prepared UCNPs@ZnxCd1-xS/TiO2 nanoparticles show excellent production of hydroxyl radicals, which are responsible for the photochemical reduction of Cr(VI) to Cr(III). This study will provide an alternative strategy for environmental wastewater treatment, making full use of solar energy.Graphical A facile chemical solution approach has been developed to synthesize UCNPs@ZnxCd1-xS/TiO2 nanocomposites for removal of Cr(VI) under irradiation of near infrared light.Graphical abstract for this article
       
  • Surface density of synthetically tuned spinel oxides of Co3+ and Ni3+ with
           enhanced catalytic activity for methane oxidation
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Zeshu Zhang, Jingwei Li, Ting Yi, Liwei Sun, Yibo Zhang, Xuefeng Hu, Wenhao Cui, Xiangguang Yang Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion. Achieving a complete oxidation of methane under 400 °C remains challenging, and whether Ni3+ or Co3+ is the active center for the catalytic combustion of methane is a controversial issue. Therefore, we designed a series of spinel oxide catalysts by exposing different amounts of Ni3+ and Co3+ deposited on the surface by hydrothermal and co-precipitation methods in order to study the influence of high oxidation state (Ni3+ and Co3+) on surface and catalytic activity. The catalytic performance increased almost linearly with increasing Ni3+ + Co3+ on the surface of the catalyst. Thus, we are convinced that Ni3+ and Co3+ both act as active centers. The amount of Ni3+ + Co3+ on a hydrothermal 60 h NiCo2O4 nanosheet surface is the highest, and reveals the best catalytic performance with T50 (50% methane conversion) at about 280 °C. 10 vol% H2O added to the system has little impact on activity, especially at high space velocities due to the long hydrothermal time with less absorbed oxygen species and crystal defects. Overall, these results help clarify methane activation mechanisms and aid the development of more efficient low-cost catalysts.Graphical The catalytic activity for complete methane oxidation positively correlates with the amount of high valence metal cations on the spinel oxide surface. The 60 h hydrothermal NiCo2O4 porous nanosheets have the best catalytic performance with T90 = 325 oC.Graphical abstract for this article
       
  • Effects of Au nanoparticle size and metal-support interaction on
           plasmon-induced photocatalytic water oxidation
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Shengyang Wang, Bin Zeng, Can Li Plasmonic photocatalysis with tunable light absorption has aroused significant attention in solar-to-chemical energy conversion. However, the energy conversion efficiency of plasmonic photocatalysts is impeded by ineffective charge separation and the lack of highly active sites for redox reactions. In this work, the Au nanoparticle size and Au-TiO2 interaction of the Au/TiO2 plasmonic photocatalyst were adjusted simultaneously using a post-calcination treatment. The visible-light-induced water oxidation activity exhibited a volcano-like relationship with the calcination temperature; the treated photocatalyst at 600 °C manifested the highest activity. Characterization with UV-visible spectra, XRD, SEM, and XPS revealed that the effect of the Au nanoparticle size and Au-TiO2 interaction were both responsible for the increase in plasmon-induced water oxidation activity.Graphical We elucidated the influence of Au nanoparticle size and Au-TiO2 interaction in plasmon-induced photocatalytic water oxidation on a Au/TiO2 photocatalyst.Graphical abstract for this article
       
  • Self-assembled three-dimensional carbon networks with accessorial Lewis
           base sites and variational electron characteristics as efficient oxygen
           reduction reaction catalysts for alkaline metal-air batteries
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Qiyu Wang, Zhian Zhang, Mengran Wang, Jie Li, Jing Fang, Yanqing Lai Heteroatom-doped carbon has been demonstrated to be one of the most promising non-noble metal catalysts with high catalytic activity and stability through the modification of the electronic and geometric structures. In this study, we develop a novel solvent method to prepare interconnected N, S co-doped three-dimensional (3D) carbon networks with tunable nanopores derived from an associated complex based on melamine and sodium dodecylbenzene sulfonate (SDBS). After the introduction of silica templates and calcination, the catalyst exhibits 3D networks with interconnected 50-nm pores and partial graphitization. With the increase of the number of Lewis base sites caused by the N doping and change of the carbon charge and spin densities caused by the S doping, the designed N, S co-doped catalyst exhibits a similar electrochemical activity to that of the commercial 20-wt% Pt/C as an oxygen reduction reaction catalyst. In addition, in an aluminum-air battery, the proposed catalyst even outperforms the commercial 5-wt% Pt/C catalyst. Both interconnected porous structures and synergistic effects of N and S contribute to the superior catalytic performance. This study paves the way for the synthesis of various other N-doped and co-doped carbon materials as efficient catalysts in electrochemical energy applications.Graphical Interconnected N, S co-doped 3D carbon networks with tunable nanopores derived from an associated complex exhibited excellent electrocatalytic and battery performances owing to the increase of the number of Lewis base sites and changes of the carbon charge and spin densities.Graphical abstract for this article
       
  • Boosting fuel cell catalysis by surface doping of W on Pd nanocubes
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Fawad Ahmad, Laihao Luo, Xu Li, Hongwen Huang, Jie Zeng The development of active and durable non-Pt electrocatalysts with well-defined microstructure is of great importance to both fuel cell applications and fundamental understanding. Herein, we report a surface-doping process to prepare well-defined W-doped Pd nanocubes with a tunable atomic percent of W from 0 to 1.5% by using the Pd nanocubes as seeds. The obtained 1.2%W-doped Pd nanocubes/C exhibited greatly enhanced electrocatalytic performance toward oxygen reduction reaction in alkaline media, presenting an enhancement factor of 4.7 in specific activity and 2.5 in mass activity compared to the activity of a commercial Pt/C catalyst. The downshift of the d-band center due to a negative charge transfer from W to Pd intrinsically accounts for such improvement in activity by weakening the adsorption of reaction intermediates. Also, the 1.2%W-doped Pd nanocubes/C showed superior catalytic properties for the ethanol oxidation reaction, showing great potential for serving as a bifunctional electrocatalyst in fuel cells.Graphical W-doped Pd nanocubes were synthesized by a surface-doping process using Pd nanocubes as seeds. The W-doped Pd nanocubes showed substantially improved fuel cell catalysis, including the alkaline oxygen reduction reaction and the ethanol oxidation reaction, which can be attributed to a downshift of the d-band center of the catalyst due to negative charge transfer from W to Pd.Graphical abstract for this article
       
  • Photocatalytic hydrogen-evolution dimerization of styrenes to synthesize
           1,2-dihydro-1-arylnaphthalene derivatives using Acr+-Mes and cobaloxime
           catalysts
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Wenxiao Cao, Chengjuan Wu, Tao Lei, Xiulong Yang, Bin Chen, Chenho Tung, Lizhu Wu We report a hydrogen-evolution dimerization of styrenes via the synergistic merger of Acr+-Mes photocatalyst and cobaloxime proton reduction catalysts. By utilizing this dual catalyst system, 1,2-dihydro-1-arylnaphthalene derivatives can be directly constructed from commercially available styrenes. Our reaction proceeds smoothly under mild conditions without the need for oxidants or hydrogen atom transfer reagents, and the sole byproduct is hydrogen gas. Mechanistic investigation suggests that the reaction is initiated by photoinduced electron transfer under visible-light irradiation.Graphical By combining Acr+-Mes and cobaloxime catalysts, hydrogen-evolution dimerization of styrenes has been achieved without the use of oxidants or HAT reagents. This reaction proceeds smoothly under mild conditions, and the sole byproduct is hydrogen gas.Graphical abstract for this article
       
  • Superior performance of iridium supported on rutile titania for the
           catalytic decomposition of N2O propellants
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Shuang Liu, Nanfang Tang, Qinghao Shang, Chuntian Wu, Guoliang Xu, Yu Cong N2O is a promising green propellant and exhibits great potential for satellite propulsion systems. It is difficult for catalytic decomposition, which is an important way to initiate the propulsion process, to occur at temperatures below 600 °C due to the high activation energy of N2O. In this work, we report an Ir supported on rutile TiO2 (Ir/r-TiO2) catalyst which exhibits a fairly high activity for high-concentration N2O decomposition. HAADF-STEM, H2-TPR, and XPS results indicate that highly dispersed Ir particles and improved oxygen mobility on the Ir/r-TiO2 could facilitate the decomposition of N2O and desorption of the adsorbed oxygen. Bridge-bonded peroxide intermediates were observed with in-situ DRIFT and herein, a detailed decomposition route is proposed.Graphical An Ir/r-TiO2 catalyst exhibits high activity for the decomposition of high concentration N2O, which is promising as a green propellant. Highly dispersed Ir particles and easy transfer of oxygen were critical for the decomposition process via bridge-bonded peroxide intermediates.Graphical abstract for this article
       
  • Photocatalytic nitrogen fixation: An attractive approach for artificial
           photocatalysis
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Rengui Li Ammonia synthesis via the Haber-Bosch process, which has been heralded as the most important invention of the 20th century, consumes massive amounts of energy, around ∼1%–2% of the world's annual energy consumption. Developing green and sustainable strategies for NH3 synthesis under ambient conditions, using renewable energy, is strongly desired, by both industrial and scientific researchers. Artificial photosynthesis for ammonia synthesis, which has recently attracted significant attention, directly produces NH3 from sunlight, and N2 and H2O via photocatalysis. This has been regarded as an ideal, energy-saving and environmentally-benign process for NH3 production because it can be performed under normal temperature and atmospheric pressure using renewable solar energy. Although sustainable developments have been achieved since the pioneering work in 1977, many challenging issues (e.g., adsorption and activation of nitrogen molecules on the surface of photocatalysts under mild conditions) have still not been well solved and the photocatalytic activities are generally low. In this miniature review, I summarize the most recent progress of photocatalytic N2 fixation for ammonia synthesis, focusing specifically on two attractive aspects for adsorption and activation of nitrogen molecules: one is engineering of oxygen vacancies, and the other is mimicking natural nitrogenase for constructing artificial systems for N2 fixation. Several representative works focusing on these aspects in artificial systems have been reported recently, and it has been demonstrated that both factors play more significant roles in photocatalytic N2 reduction and fixation under ambient conditions. At the end of the review, I also give some remarks and perspective on the existing challenges and future directions in this field.Graphical Photocatalytic nitrogen fixation for ammonia synthesis is one of the attractive approaches in artificial photosynthesis, which directly producing NH3 from sunlight, N2 and H2O via photocatalysis.Graphical abstract for this article
       
  • Covalent organic frameworks as heterogeneous catalysts
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Hui Hu, Qianqian Yan, Rile Ge, Yanan Gao Covalent organic frameworks (COFs), established as an emerging class of crystalline porous polymers with high surface area, structural diversity, and designability, attract much interest and exhibit potential applications in catalysis. In this review, we summarize the use of COFs as a versatile platform to develop heterogeneous catalysts for a variety of chemical reactions. Catalytic COFs are categorized in accordance with the types of active sites, involving single functional active sites, bifunctional active sites, and metal nanoparticles (NPs) embedded in pores. Special emphasis is placed on the deliberate or incidental synthesis strategies, the stability, the heterogeneity, and the shape/size selectivity for COF catalysis. Moreover, a description of the application of COFs as photocatalysts and electrocatalysts is presented. Finally, the prospects of COFs in catalysis and remaining issues in this field are indicated.Graphical Use of covalent organic frameworks (COFs) as a versatile platform to develop heterogeneous catalysts is of great interest. The recent progress and challenges for catalytic COFs for a variety of chemical reactions are discussed and summarized.Graphical abstract for this article
       
  • Transition metal (Mo, Fe, Co, and Ni)-based catalysts for electrochemical
           CO2 reduction
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Jinhui Hao, Weidong Shi The electrochemical conversion of CO2 into value-added chemicals and fuels has attracted widespread concern since it realizes the recycling of greenhouse gases. Production of new materials lies at the very core of this technology as it enables the improvement of developmental efficiency and selectivity by chemical optimization of morphology and electronic structure. Transition metal-based catalysts are particularly appealing as their d bands have valence electrons which are close to the Fermi level and hence overcome the intrinsic activation barriers and reaction kinetics. The study of Mo, Fe, Co, and Ni-based materials in particular is a very recent research subject that offers various possibilities in electrochemical CO2 reduction applications. Herein, we summarize the recent research progress of Mo, Fe, Co, and Ni-based catalysts and their catalytic behavior in electrochemical CO2 reduction. We particularly focus on the relationship between structures and properties, with examples of the key features accounting for the high efficiency and selectivity of the CO2 reduction process. The most significant experimental and theoretical improvements are highlighted. Finally, we concisely discuss the scientific challenges and opportunities for transition metal-based catalysts.Graphical Transition metal (Mo, Fe, Co and Ni)-based catalysts with well-defined d-state structure provided a fast electron transfer process for intermediate adsorption and thus exhibited high intrinsic activity for the electrochemical CO2 reduction process.Graphical abstract for this article
       
  • Focus on the Chinese revolution of catalysis based on catalytic solutions
           for the vital demands of society and economy
    • Abstract: Publication date: July 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 7Author(s): Yangdong Wang, Jing Shi, Zhonghao Jin, Zaiku Xie Catalysis is one of the most cross-cutting technologies in the chemical industry, intensely influencing our daily society. Its practical application is closely related to the engineering disciplines. At present, the academic and industrial research on catalysis in our country has made great breakthroughs in fields like hydrocarbon production, oil-quality upgrading processes, green chemical engineering, and other energy and chemical users of catalysis. In this paper, we attempt to summarize the industrial catalysis achievements and present a discussion on the direction and the development strategy for catalysis, based on economic and social demands.Graphical The milestones of China's significant industrial catalysis were summarized, and a discussion on the direction and strategy of catalysis, based on economic and social demands, was presented. Focusing on the revolution of catalysis and promoting collaborative innovation between academic and industrial research should be the main concerns for furthering catalysis.Graphical abstract for this article
       
  • Simple synthesis of nitrogen-doped carbon spheres as a highly efficient
           metal-free electrocatalyst for the oxygen reduction reaction
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Jinhui Tong, Wenyan Li, Lili Bo, Wenhui Wang, Yuliang Li, Tao Li, Qi Zhang, Haiyan Fan In the present work, nitrogen-doped carbon spheres were synthesized through a simple hydrothermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, respectively. The ratio of melamine to glucose and annealing temperature were optimized. The final optimal sample exhibited a catalytic activity for the oxygen reduction reaction (ORR) that was superior than that of commercial 20%Pt/C in 0.1 mol/L KOH. It revealed an onset potential of –22.6 mV and a half-wave potential of –133.6 mV (vs. Ag/AgCl), which are 7.2 and 5.9 mV more positive than those of the 20%Pt/C catalyst, respectively, as well as a limiting current density of 4.6 mA/cm2, which is 0.2 mA/cm2 higher than that of the 20%Pt/C catalyst. The catalyst also exhibited higher stability and superior durability against methanol than 20%Pt/C. Moreover, ORRs on this catalyst proceed through a more effective 4e− path. The above mentioned superiority of the as-prepared catalyst makes it promising for fuel cells.Graphical Porous N-doped carbon spheres were simply synthesized using inexpensive raw materials. The optimal sample exhibited a more effective ORR catalytic activity than commercial 20%Pt/C in 0.1 mol/L KOH.Graphical abstract for this article
       
  • One-step aldol condensation reaction of dimethoxymethane and methyl
           acetate over supported Cs/ZSM-35 zeolite catalysts
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Zhanling Ma, Xiangang Ma, Hongchao Liu, Wenliang Zhu, Xinwen Guo, Zhongmin Liu This study was performed for the development of a green and promising approach for the synthesis of methyl acrylate and acrylic acid by a one-step aldol condensation reaction of dimethoxymethane and methyl acetate over cesium oxide-supported on ZSM-35 zeolite catalysts; the effect of base sites as well as acid sites on the aldol condensation reaction was studied in detail. It was found that base sites were harmful for aldol condensation due to their failure in catalyzing the decomposition of dimethoxymethane precursor into formaldehyde, whereas the acid site was indispensable for the reaction to proceed. This reaction cannot take place without an acid site. Although acid sites in H-form of the zeolite (HZSM-35) are indispensable for the aldol condensation reaction, not all of them tend to favor this reaction. A strong acid catalyzes methanol-to-olefin-like reactions resulting in hydrocarbon byproducts, which are finally transferred to hard coke. Medium strong acids and weak acids are great candidates for the target aldol condensation reaction with high activity and selectivity. A γ-Al2O3 sample with abundant weak-strength Lewis acid sites, together with a few medium-strong-strength acid sites, performs well with a high activity and considerable stability during the synthesis of methyl acrylate and acrylic acid.Graphical Acidity is indispensable for the aldol condensation reaction of DMM with MAc to prepare acrylic acid and its ester, whereas alkalinity is harmful.Graphical abstract for this article
       
  • Glycerol hydrogenolysis to n-propanol over Zr-Al composite
           oxide-supported Pt catalysts
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Chuang Li, Bo He, Yu Ling, Chi-Wing Tsang, Changhai Liang Zr-Al mixed oxide supported Pt catalysts with different Zr/Al mole ratios (2.5%Pt/ZrxAl1–xOy) were synthesized by an impregnation method and used for the selective hydrogenolysis of glycerol to n-propanol in an autoclave reactor. The catalysts were fully characterized by X-ray powder diffraction, Brunauer-Emmett-Teller surface area analysis, CO chemisorption, H2 temperature- programmed reduction, pyridine-infrared spectroscopy, and NH3-temperature-programmed desorption. The results revealed that the Zr/Al ratio on the support significantly affected the size of the platinum particles and the properties of the acid sites on the catalysts. The catalytic performance was well correlated with the acidic properties of the catalyst; specifically, more acid sites contributed to the conversion and strong acid sites with a specific intensity contributed to the deep dehydration of glycerol to form n-propanol. Among the tested catalysts, 2.5 wt% Pt/Zr0.7Al0.3Oy exhibited excellent selectivity for n-propanol with 81.2% glycerol conversion at 240 °C and 6.0 MPa H2 pressure when 10% aqueous glycerol solution was used as the substrate. In addition, the effect of various reaction parameters, such as H2 content, reaction temperature, reaction time, and number of experimental cycles were studied to determine the optimized reaction conditions and to evaluate the stability of the catalyst.Graphical Zr-Al mixed oxide-supported Pt catalysts with different Zr/Al mole ratios were synthesized by an impregnation method and used in the selective hydrogenolysis of glycerol to n-propanol with high activity, selectivity, and absolute reusability.Graphical abstract for this article
       
  • Olefin oligomerization via new and efficient Brönsted acidic ionic
           liquid catalyst systems
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Guoqin Wang, Heyuan Song, Ruiyun Li, Zhen Li, Jing Chen Olefin oligomerization reaction catalyzed by new catalyst systems (a Brönsted-acidic ionic liquid as the main catalyst and tricaprylylmethylammonium chloride as the co-catalyst) has been investigated. The synthesized Brönsted acidic ionic liquids were characterized by Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV), 1H nuclear magnetic resonance (NMR), and 13C NMR to analyze their structures and acidities. The influence of different ionic liquids, ionic liquid loading, different co-catalysts, catalyst ratios (mole ratio of ionic liquid to co-catalyst), reaction time, pressure, temperature, solvent, source of reactants, and the recycling of catalyst systems was studied. Among the synthesized ionic liquids, 1-(4-sulfonic acid)butyl-3-hexylimidazolium hydrogen sulfate ([HIMBs]HSO4) exhibited the best catalytic activity under the tested reaction conditions. The conversion of isobutene and selectivity of trimers were 83.21% and 35.80%, respectively, at the optimum reaction conditions. Furthermore, the catalyst system can be easily separated and reused; a feasible reaction mechanism is proposed on the basis of the distribution of experimental products.Graphical In this work, light olefin (ethylene, propylene, and isobutene) oligomerization was carried out using Brönsted-acidic ionic liquids and co-catalyst systems, which exhibit good catalytic activity. Further, the structures of the resultant oligomers and their selectivity were analyzed.Graphical abstract for this article
       
  • Preparation and catalytic properties of mesoporous nV-MCM-41 for propane
           oxidative dehydrogenation in the presence of CO2
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Zai-Fang Han, Xu-Liang Xue, Jian-Min Wu, Wan-Zhong Lang, Ya-Jun Guo The nV-MCM-41 catalysts were prepared by one-step hydrothermal synthesis and applied to the oxidative dehydrogenation of propane (ODHP) in the presence of CO2. Several state-of-the-art characterization methods were performed to explore the correlation between catalytic performance and the physicochemical characterizations of the catalysts. Because moderate amounts of V species were introduced into the framework of MCM-41, the catalyst maintained a large specific surface area, a highly ordered mesoporous structure, and highly dispersed V active sites (monomeric and dimeric V oxide species), while the high-vanadium-doping catalysts caused an enhancement in the number of acidic sites and V2O5 crystallites. The ODHP reaction showed that the 6.8V-MCM-41 (V content 6.8 wt%) catalyst exhibits high activity and stability, and the C3H8/CO2 molar ratio (1:4) was suitable. The promoting effect of CO2 on the oxidative dehydrogenation of ODHP was demonstrated as the reaction coupling mechanism and “lattice oxygen” mechanism.Graphical nV-MCM-41 catalysts prepared by the one-step method maintain highly ordered mesoporous structures and large specific surface areas. The 6.8V-MCM-41 catalysts exhibit highly dispersed V oxide and excellent catalytic performance in the oxidative dehydrogenation of propane.Graphical abstract for this article
       
  • Preparation of N-vacancy-doped g-C3N4 with outstanding photocatalytic H2O2
           production ability by dielectric barrier discharge plasma treatment
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Xuhe Li, Jian Zhang, Feng Zhou, Hongliang Zhang, Jin Bai, Yanjuan Wang, Haiyan Wang Dielectric barrier discharge (DBD) plasma is considered to be a promising method to synthesize solid catalysts. In this work, DBD plasma was used to synthesize a nitrogen-vacancy-doped g-C3N4 catalyst in situ for the first time. X-ray diffraction, N2 adsorption, ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, electron paramagnetic resonance, O2 temperature-programmed desorption, and photoluminescence were used to characterize the obtained catalysts. The photocatalytic H2O2 production ability of the as-prepared catalyst was investigated. The results show that plasma treatment influences the morphology, structure, and optical properties of the as-prepared catalyst. Nitrogen vacancies are active centers, which can adsorb reactant oxygen molecules, trap photoelectrons, and promote the transfer of photoelectrons from the catalyst to the adsorbed oxygen molecules for the subsequent reduction reaction. This work provides a new strategy for synthesizing g-C3N4-based catalysts.Graphical N vacancies can chemisorb and activate O2 molecules, thus promoting the transfer of photogenerated electrons from g-C3N4 to adsorbed O2 molecules, leading to enhanced photocatalytic H2O2 production ability.Graphical abstract for this article
       
  • Green catalytic oxidation of benzyl alcohol over Pt/ZnO in base-free
           aqueous medium at room temperature
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Juanjuan Liu, Shihui Zou, Jiachao Wu, Hisayoshi Kobayashi, Hongting Zhao, Jie Fan The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green solvent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the selective oxidation of benzyl alcohol at room temperature under base-free aqueous conditions. Experimental observations and density functional theory calculations suggest that ZnO as a support can facilitate the adsorption of benzyl alcohol, which subsequently reacts with the activated oxygen species on the Pt catalyst, producing benzaldehyde. The resulting solid achieves a high conversion (94.1 ± 5.1% in 10 h) of benzyl alcohol and nearly 100% selectivity to benzaldehyde with ambient air as the oxidant. In addition, by introducing a small amount of Bi (1.78 wt%) into Pt/ZnO, we can further enhance the activity by 350%.Graphical ZnO as a support can facilitate the adsorption of benzyl alcohol, which subsequently reacts with an activated oxygen species on a Pt catalyst to produce benzaldehyde at room temperature under base-free aqueous conditions.Graphical abstract for this article
       
  • Hydrogenation of 2-ethylanthraquinone with bimetallic monolithic
           catalysts: An experimental and DFT study
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Yanyan Guo, Chengna Dai, Zhigang Lei We studied the hydrogenation of 2-ethylanthraquinone (eAQ) over Pd/SiO2/COR (COR = cordierite) monometallic and Pd-M/SiO2/COR (M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts, which were prepared by the co-impregnation method. Detailed investigations showed that the particle sizes and structures of the Pd-M (M = Ni, Fe, Mn, and Cu) bimetallic monolithic catalysts were greatly affected by the second metal M and the mass ratio of Pd to the second metal M. By virtue of the small particle size and the strong interaction between Pd and Ni of Pd-Ni alloy, Pd-Ni bimetallic monolithic catalysts with the mass ratio of Pd/Ni = 2 achieved the highest H2O2 yield (7.5 g/L) and selectivity (95.3%). Moreover, density functional theory calculations were performed for eAQ adsorption to gain a better mechanistic understanding of the molecule-surface interactions between eAQ and the Pd(1 1 1) or PdM(1 1 1) (M = Ni, Fe, Mn, and Cu) surfaces. It was found that the high activity of the bimetallic Pd-Ni catalyst was a result of strong chemisorption between Pd3Ni1 (1 1 1) and the carbonyl group of eAQ.Graphical The high catalytic activity of Pd-Ni/SiO2/cordierite monolithic catalyst is attributed to the small particle size, the strong interaction between Pd and Ni of Pd-Ni alloy and stronger adsorption between Pd3Ni1 (1 1 1) and the carbonyl group of eAQ.Graphical abstract for this article
       
  • Acid-promoted Ir-La-S/AC-catalyzed methanol carbonylation on single atomic
           active sites
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Zhou Ren, Yuan Lyu, Siquan Feng, Xiangen Song, Yunjie Ding Highly active Ir-La-S/AC catalyst was successfully prepared by co-impregnation of an activated carbon (AC) carrier with a sulfuric acid solution of Ir and La species and compared with a traditionally prepared Ir-La/AC catalyst. High angle annular dark-field-scanning transmission electron microscopy (HAADF-STEM) measurement results show that most of the Ir species on Ir-La-S/AC exist as single atomic sites, while those on Ir-La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir-La-S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF (turn-over-frequency) of 2760 h−1, which was distinctly higher than that achieved by the Ir-La/AC catalyst (approximately 1000 h−1). Temperature-programmed desorption of ammonia (NH3-TPD) result shows that the addition of sulfuric acid during the preparation procedure results in significantly more acidic sites on Ir-La-S/AC than those on Ir-La/AC, which plays a key role in the enhancement of CO insertion as the rate-determining step. Temperature-programmed reduction (TPR) and in situ X-ray photoelectron spectroscopy reveal that Ir species are more reducible, and that more Ir+ might be formed by activation of Ir-La-S/AC than those on the Ir-La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir3+ species as an essential step for CH3I regeneration and acetyl formation.Graphical By addition of S species, the acid-promoted single-site Ir-La-S/AC catalyst, which displayed much high activity of carbonylation, was successfully prepared by co-impregnation method and applied in vapor-phase heterogeneous carbonylation of methanol.Graphical abstract for this article
       
  • Preparation of a fullerene[60]-iron oxide complex for the photo-fenton
           degradation of organic contaminants under visible-light irradiation
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Cong-yang Zou, Ze-da Meng, Wen-chao Ji, Shou-qing Liu, Zhemin Shen, Yuan Zhang, Ni-shan Jiang Iron oxide (Fe2O3) was doped onto fullerene[60] (C60) to form a C60-Fe2O3 composite using an easy and scalable impregnation method. The as-prepared C60-Fe2O3 samples were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, UV-vis absorption spectroscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy. The photocatalytic activity of the C60-Fe2O3 catalyst was evaluated by examining the degradation of methylene blue (MB), rhodamine B (RhB), methyl orange (MO), and phenol under visible light (λ> 420 nm) in the presence of hydrogen peroxide. The results showed that the catalyst exhibited excellent catalytic properties over a wide pH range 3.06–10.34. Under optimal conditions, 98.9% discoloration and 71% mineralization of MB were achieved in 80 min. Leaching test results indicated that the leaching of iron from the catalyst was negligible and that the catalyst had a high photocatalytic activity after five reaction cycles. The catalyst was also efficient in the degradation of RhB, MO, and phenol. These findings could be attributed to the synergetic effects of C60 and Fe2O3. We used active species trapping experiments to determine the main active oxidant in the photocatalytic reaction process and found that hydroxyl radicals played a major role in the entire process.Graphical This is a highly efficient heterogeneous photo-Fenton system. The C60 on the Fe2O3 surface is expected to improve the photocatalytic behavior. ·OH plays a major role in the system and degrades the organic compounds to CO2 and H2O.Graphical abstract for this article
       
  • Facile in-situ synthesis and deposition of monodisperse palladium
           nanoparticles on polydopamine-functionalized silica gel as a heterogeneous
           and recyclable nanocatalyst for aerobic oxidation of alcohols
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Hojat Veisi, Ahmad Nikseresht, Shahin Mohammadi, Saba Hemmati This paper describes a facile in-situ synthesis of palladium nanoparticles (Pd NPs) on silica gel/polydopamine composite (SiO2/PDA) without any stabilizer or reducing agent. In this approach, palladium ions were adsorbed on SiO2/PDA surfaces by immersing the PDA-coated SiO2 particles in a palladium plating bath. Then, they were reduced in situ to Pd nanoclusters by the reducing ability of PDA's N-containing groups. The structure, morphology, and physicochemical properties of the synthesized nanocomposites were characterized by different analytical techniques such as high-resolution transmission electron microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, inductively coupled plasma and Fourier-transform infrared spectroscopy. The Pd NPs capped by the PDA groups had a strikingly small size (30–40 nm). SiO2/PDA/Pd NPs exhibited high catalytic activity as a recyclable nanocatalyst in the aerobic oxidation of alcohols. Furthermore, recovery and multiple reuse of the catalyst revealed no detectable activity loss.Graphical This study described a protocol for in-situ synthesis of Pd nanoparticles immobilized on polydopamine coated-silica gel as a novel nanocatalyst for aerobic oxidation of alcohols.Graphical abstract for this article
       
  • N-doped carbon modified Pt/CNTs synthesized by atomic layer deposition
           with enhanced activity and stability for methanol electrooxidation
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Huimin Yang, Baiyan Zhang, Bin Zhang, Zhe Gao, Yong Qin A Pt/CNTs catalyst coated with N-doped carbon (xNC-Pt/CNTs) is synthesized by atomic layer deposition (ALD) and applied in methanol electrooxidation reaction. Pt nanoparticles and polyimide (PI) are sequentially deposited on carbon nanotubes (CNTs) by ALD. After annealing at 600 °C in H2 atmosphere, the PI is carbonized to produce porous N-doped carbon. Upon coating with a moderately thick layer of N-doped carbon, the optimized 50NC-Pt/CNTs show higher activity, better long-term stability, and improved CO resistance towards methanol electrooxidation compared with Pt/CNTs and commercial Pt/C (20 wt%). X-ray photoelectron spectroscopy characterization result indicates that the Pt–CO bond is weakened after N-doped carbon coating and CO adsorption on the Pt surface is weakened, leading to superior electrocatalytic performance.Graphical Uniform polyimide films are deposited on the outer face of a Pt/CNTs catalyst by atomic layer deposition. After pyrolysis, polyimide films are converted to porous N-doped carbon films. By precisely adjusting the thickness of the polyimide films, the optimized 50NC-Pt/CNTs catalyst shows 1.7-fold enhancement in activity in the methanol electrooxidation reaction.Graphical abstract for this article
       
  • Pt/Nb-WO x for the chemoselective hydrogenolysis of glycerol to
           1,3-propanediol: Nb dopant pacifying the over-reduction of WO x supports
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Man Yang, Xiaochen Zhao, Yujing Ren, Jia Wang, Nian Lei, Aiqin Wang, Tao Zhang Selective hydrogenolysis of glycerol to 1,3-propanediol (1,3-PD) is an important yet challenging method for the transformation of biomass into value-added chemicals due to steric hindrance and unfavorable thermodynamics. In previous studies, chemoselective performances were found demanding and sensitive to H2 pressure. In this regard, we manipulate the chemical/physical characteristics of the catalyst supports via doping Nb into WOx and prepared 1D needle-, 2D flake-, and 3D sphere-stack mesoporous structured Nb-WOx with increased surface acid sites. Moreover, Nb doping can successfully inhibit the over-reduction of active W species during glycerol hydrogenolysis and substantially broaden the optimal H2 pressure from 1 to 5 MPa. When Nb doping is 2%, supported Pt catalysts showed promising performance for the selective hydrogenolysis of glycerol to 1,3-PD over an unprecedentedly wide H2 pressure range, which will guarantee better catalyst stability in the long run, as well as expand their applications to other hydrogen-related reactions.Graphical Pt/2%Nb-WOx successfully reconciled the conflicts between H2 activation and W-reduction and demonstrated a promising performance in the selective hydrogenolysis of glycerol to 1,3-propanediol across an unprecedentedly wide H2 pressure range.Graphical abstract for this article
       
  • In situ doping brushite on zinc manganese oxide toward enhanced water
           oxidation performance: Mimicry of an oxygen-evolving complex
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Miao Jiang, Junying Chen, Yingwei Li We report in situ doping of brushite on zinc manganese oxide (ZMO), fabricated by calcining a Mn(II) oxalate-impregnated metal-organic framework. The doping process was conducted in combination with the photocatalytic water oxidation reaction which was catalyzed by ZMO in neutral phosphate-buffered aqueous solution containing [Ru(bpy)3]2+-Na2S2O8 and calcium(II) triflate salt, exhibiting greatly enhanced water oxidation performance with optimized turnover frequency of 0.18 mmolO2 molMn−1 s−1. Different analytical techniques indicated that photodeposited calcium-phosphate (CaP) acted as a co-catalyst to promote the O2 evolution activity of ZMO. This system involved the use of manganese oxide and calcium ion, and the operation was conducted under ambient temperature and neutral conditions, thus, it efficiently mimicked the oxygen-evolving complex in photosystem II.Graphical Brushite was in situ doped on MOF-templated zinc-manganese oxide via photodeposition in neutral water containing phosphate and calcium(II) ions, and was responsible for enhanced photocatalytic water oxidation performance.Graphical abstract for this article
       
  • Chemical transformation of sugars into amino acids
    • Abstract: Publication date: June 2018Source: Chinese Journal of Catalysis, Volume 39, Issue 6Author(s): Tao ZhangGraphical Amino acids were produced from woody biomass intermediates through Ru/CNT catalyst in a rapid and efficient chemical approach.Graphical abstract for this article
       
 
 
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