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  Subjects -> MATHEMATICS (Total: 909 journals)
    - APPLIED MATHEMATICS (75 journals)
    - GEOMETRY AND TOPOLOGY (20 journals)
    - MATHEMATICS (676 journals)
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MATHEMATICS (676 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: 3)
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: 25)
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: 6)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
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: 5)
Advances in Difference Equations     Open Access   (Followers: 2)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 2)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Mathematical Physics     Open Access   (Followers: 5)
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: 6)
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: 9)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Al-Jabar : Jurnal Pendidikan Matematika     Open Access  
Algebra and Logic     Hybrid Journal   (Followers: 4)
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: 4)
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: 3)
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: 11)
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: 8)
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: 5)
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   (Followers: 1)
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: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
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: 21)
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: 3)
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  
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: 21)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 11)
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: 20)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 1)
CHANCE     Hybrid Journal   (Followers: 6)
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: 3)
COMBINATORICA     Hybrid Journal  
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: 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: 6)
Concrete Operators     Open Access   (Followers: 4)
Confluentes Mathematici     Hybrid Journal  
Contributions to Game Theory and Management     Open Access  
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  
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: 28)
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Dhaka University Journal of Science     Open Access  
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 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 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 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  
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: 5)
European Journal of Mathematics     Hybrid Journal   (Followers: 1)

        1 2 3 4 | Last

Journal Cover Chinese Journal of Catalysis
  [SJR: 0.6]   [H-I: 29]   [2 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 1872-2067
   Published by Elsevier Homepage  [3118 journals]
  • ZnO-ZrO2 solid solution catalyst for highly selective hydrogenation of CO2
           to methanol
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Tao Zhang
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Conversion of biomass to chemicals over zirconium phosphate-based
           catalysts
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Difan Li, Wenxiu Ni, Zhenshan Hou
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Recent progress in Ag3PO4-based all-solid-state Z-scheme photocatalytic
           systems
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Ming Ge, Zhenlu Li
      Heterogeneous semiconductor photocatalysis is a promising green technology solution to energy and environmental problems. Traditional photocatalyst TiO2, with a wide band gap of 3.2 eV, can only be excited by UV light and utilizes less than 4% of solar energy. Silver phosphate (Ag3PO4) is among the most active visible-light-driven photocatalysts reported. Unfortunately, unwanted photocorrosion is the main obstacle to the practical application of Ag3PO4. Much effort has been made in recent years to address this issue and further enhance the photocatalytic performance of Ag3PO4. The construction of Z-scheme photocatalytic systems that mimic natural photosynthesis is a promising strategy to improve the photocatalytic activity and stability of Ag3PO4. This brief review concisely summarizes and highlights recent research progress in Ag3PO4-based all-solid-state Z-scheme photocatalytic systems with or without a solid-state electron mediator, focusing on their construction, application, and reaction mechanism. Furthermore, the challenges and future prospects of Ag3PO4-based Z-scheme photocatalytic systems are discussed.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Synergistic photocatalytic effect of porous g-C3N4 in a
           Cr(VI)/4-chlorophenol composite pollution system
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Kai Wei, Kexin Li, Zhenxing Zeng, Yuhua Dai, Liushui Yan, Huiqin Guo, Xubiao Luo
      The photocatalytic reduction of aqueous Cr(VI) to Cr(III) was preliminarily studied using porous g-C3N4 as a photocatalyst under acidic conditions. The observed synergistic photocatalytic effect of porous g-C3N4 on a Cr(VI)/4-chlorophenol (4-CP) composite pollution system was further studied under different pH conditions. Compared with single-component photocatalytic systems for Cr(VI) reduction or 4-CP degradation, the Cr(VI) reduction efficiency and 4-CP degradation efficiency were simultaneously improved in the Cr(VI)/4-CP composite pollution system. The synergistic photocatalytic effect in the Cr(VI)/4-CP composite pollution system can be attributed to the accelerated redox reaction between dichromate and 4-CP by electron transfer with porous g-C3N4.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Electrocatalytic water oxidation by a nickel oxide film derived from a
           molecular precursor
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Fei Li, Hua Li, Yong Zhu, Jian Du, Yong Wang, Licheng Sun
      In this study, we fabricated a NiO x film by electrodeposition of an ethanediamine nickel complex precursor (pH = 11) on a fluorine-doped tin oxide substrate. The resulting film is robust and exhibits high catalytic activity for electrochemical water oxidation. Water oxidation is initiated with an overpotential of 375 mV (1 mA/cm2) and a steady current density of 8.5 mA/cm2 is maintained for at least 10 h at 1.3 V versus the normal hydrogen electrode. Kinetic analysis reveals that there is a 2e−/3H+ pre-equilibrium process before the chemical rate-determining step. The low-cost preparation, robustness, and longevity make this catalyst competitive for applications in solar energy conversion and storage.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Effects of indium on Ni/SiO2 catalytic performance in hydrodeoxygenation
           of anisole as model bio-oil compound: Suppression of benzene ring
           hydrogenation and C–C bond hydrogenolysis
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Xiaofei Wang, Jixiang Chen
      SiO2-supported monometallic Ni and bimetallic Ni-In catalysts were prepared and used for hydrodeoxygenation of anisole, which was used as a model bio-oil compound, for BTX (benzene, toluene, and xylene) production. The effects of the Ni/In ratio and Ni content on the structures and performances of the catalysts were investigated. The results show that In atoms were incorporated into the Ni metal lattice. Although the Ni-In bimetallic crystallites were similar in size to those of monometallic Ni at the same Ni content, H2 uptake by the bimetallic Ni-In catalyst was much lower than that by monometallic Ni because of dilution of Ni atoms by In atoms. Charge transfer from In to Ni was observed for the bimetallic Ni-In catalysts. All the results indicate intimate contact between Ni and In atoms, and the In atoms geometrically and electronically modified the Ni atoms. In the hydrodeoxygenation of anisole, although the activities of the Ni-In bimetallic catalysts in the conversion of anisole were lower than that of the monometallic Ni catalyst, they gave higher selectivities for BTX and cyclohexane as a result of suppression of benzene ring hydrogenation and C–C bond hydrogenolysis. They also showed lower methanation activity. These results will be useful for enhancing carbon yields and reducing H2 consumption. In addition, the lower the Ni/In ratio was, the greater was the effect of In on the catalytic performance. The selectivity for BTX was primarily determined by the Ni/In ratio and was little affected by the Ni content. We suggest that the performance of the Ni-In bimetallic catalyst can be ascribed to the geometric and electronic effects of In.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • In situ preparation of mesoporous Fe/TiO2 catalyst using Pluronic
           F127-assisted sol-gel process for mid-temperature NH3 selective catalytic
           reduction
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Yulin Li, Xiaojin Han, Yaqin Hou, Yaoping Guo, Yongjin Liu, Ning Xiang, Yan Cui, Zhanggen Huang
      An Fe/TiO2 catalyst with uniform mesopores was synthesized using Pluronic F127 as a structure-directing agent. This catalyst was used for selective catalytic reduction of NO with NH3. The catalytic activity and resistance to H2O and SO2 of Fe/TiO2 prepared by a template method were better than those of catalysts synthesized using impregnation and coprecipitation. The samples were characterized using N2-physisorption, transmission electron microscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and in situ diffuse reflectance infrared Fourier-transform spectroscopy. The results showed that Pluronic F127 acted as a structural and chemical promoter; it not only promoted the formation of a uniform mesoporous structure, leading to a higher surface area, but also improved dispersion of the active phase. In addition, the larger number of Lewis acidic sites, indicated by the presence of coordinated NH3 species (1188 cm−1) and the N–H stretching modes of coordinated NH3 (3242 and 3388 cm−1), were beneficial to mid-temperature selective catalytic reduction reactions.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Copper-catalyzed amination of phenylboronic acids with benzofurazan
           1-oxides
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Manman Wang, Yunyun Li, Fen Wang, Xingwei Li
      CuCl/Phen can catalyze the C–N coupling between arylboronic acid and benzofurazan 1-oxide. This reaction occurred under mild and redox-neutral conditions with benzofurazan 1-oxide as an aminating reagent via ring scission, leading to a bifunctionalized aminonitrobenzene.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • TiO2 composite nanotubes embedded with CdS and upconversion nanoparticles
           for near infrared light driven photocatalysis
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Wanni Wang, Fu Zhang, Chuanling Zhang, Yang Wang, Wei Tao, Sheng Cheng, Haisheng Qian
      We report a colloidal process to coat a layer of TiO2 onto SiO2 composite nanofibers containing embedded CdS and upconversion nanoparticles (UCNPs). The SiO2 composite nanofibers were fabricated by electrospinning. To improve the energy transfer efficiency, UCNPs and CdS nanoparticles were bound in close proximity to each other within the SiO2 matrix. β-NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%) core–shell nanoparticles were used as nanotransducers for near infrared light. These nanoparticles exhibited enhanced upconversion fluorescence compared with β-NaYF4:Yb(30%),Tm(0.5%) or β–NaYF4:Yb(30%),Tm(0.5%)@NaYF4 nanoparticles. The morphologies, size and chemical compositions have been extensively investigated using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS), respectively. The TEM images showed that the TiO2 composite nanotubes were embedded with a large amount of UCNPs and CdS nanoparticles. The composite TiO2 nanotubes degraded more than 90% of rhodamine B (RhB) dye during 20 min of irradiation by simulated solar light. In particular, more than 50% of RhB was decomposed in 70 min, under irradiation of near infrared light (NIR). This high degradation was attributed to the full spectrum absorption of solar light, and the enhanced transfer efficiency for near infrared light. The as-prepared nanostructures can harness solar energy, and provide an alternative to overcome energy shortages and environmental protection.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Solid base catalysts derived from Ca-M-Al (M = Mg, La, Ce, Y) layered
           double hydroxides for dimethyl carbonate synthesis by transesterification
           of methanol with propylene carbonate
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Yunhui Liao, Feng Li, Xin Dai, Ning Zhao, Fukui Xiao
      Composite solid base catalysts derived from Ca-M-Al (M = Mg, La, Ce, Y) layered double hydroxides (LDH) were synthesized, characterized and applied to the transesterification of methanol with propylene carbonate. X-ray diffraction analyses of the catalysts show that all of the catalysts were in the form of composite oxides. Compared with the Ca-Al LDH catalyst, the specific surface areas and pore volumes of the catalysts were increased with the introduction of Mg, La or Ce. The catalytic performance of these catalysts increases in the order of Ca-Y-Al < Ca-Al < Ca-Ce-Al < Ca-La-Al < Ca-Mg-Al, which is consistent with the total surface basic amounts of these materials and the formation of especially strong basic sites following modification with Mg and La. The Ca-Mg-Al catalyst shows the highest (Ca+Mg):Al atomic ratio, indicating that it likely contains more unsaturated O2– ions, providing it with the highest concentration of very strong basic sites. The recyclability of these catalysts is improved following the addition of Mg, La, Ce or Y, with the Ca-Mg-Al maintaining a high level of activity after ten recycling trials. X-ray diffraction analyses of fresh and used Ca-Mg-Al demonstrate that this catalyst is exceptionally stable, which could be of value in practical applications related to heterogeneous catalysis.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Selective suppression of toluene formation in solvent-free benzyl alcohol
           oxidation using supported Pd-Ni bimetallic nanoparticles
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Jianwei Che, Mengjia Hao, Wuzhong Yi, Hisayoshi Kobayashi, Yuheng Zhou, Liping Xiao, Jie Fan
      The solvent-free oxidation of benzyl alcohol was studied using supported Pd-Ni bimetallic nanoparticles. Compared with monometallic Pd, the addition of Ni to Pd was found to be effective in suppressing the nondesired product toluene, thereby enhancing the selectivity towards benzaldehyde. This result was attributed to a dual effect of Ni addition: the weakening of dissociative adsorption of benzyl alcohol and the promotion of oxygen species involved in the oxidation pathway.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Synthesis of FER zeolite with piperidine as structure-directing agent and
           its catalytic application
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Weifeng Chu, Fucun Chen, Ce Guo, Xiujie Li, Xiangxue Zhu, Yang Gao, Sujuan Xie, Shenglin Liu, Nan Jiang, Longya Xu
      The synthesis of ferrierite (FER) zeolite using piperidine as an organic structure-directing agent was investigated. X-ray diffraction, X-ray fluorescence, N2-adsorption, and scanning electron microscopy were used to characterize the crystal phases, textural properties, and particle morphologies of the zeolite samples. The crystallization behavior of the FER zeolite was found to be directly related to crystallization temperature. At 150 °C, pure FER phase was observed throughout crystallization. At 160–170 °C, MWW phase appeared first and gradually transformed into FER phase over time, indicating that the FER phase was thermodynamically favored. In the piperidine-Na2O-H2O synthetic system, alkalinity proved to be the crucial factor determining the size and textural properties of FER zeolite. Furthermore, the obtained FER samples exhibited good catalytic performance in the skeletal isomerization of 1-butene.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Preparation of gold clusters on metal oxides by deposition-precipitation
           with microwave drying and their catalytic performance for CO and sulfide
           oxidation
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Ayako Taketoshi, Tamao Ishida, Hironori Ohashi, Tetsuo Honma, Masatake Haruta
      Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition-precipitation followed by microwave irradiation as a drying method and then calcination. The drying method influenced the size of the Au particles. Au(III) was partly reduced during conventional oven drying, resulting in Au aggregates. In contrast, Au(III) was preserved during microwave drying owing to rapid and uniform heating, and the Au diameter was minimized to 1.4 nm on Al2O3. This method can be applied to several metal oxide supports having different microwave absorption efficiencies, such as MnO2, Al2O3, and TiO2. These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Low-cost and efficient visible-light-driven CaMg(CO3)2@Ag2CO3 microspheres
           fabricated via an ion exchange route
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Jian Tian, Zhen Wu, Zhen Liu, Changlin Yu, Kai Yang, Lihua Zhu, Weiya Huang, Yang Zhou
      CaMg(CO3)2 microspheres were prepared and used as hard templates to fabricate a series of CaMg(CO3)2@Ag2CO3 composite microspheres via a fast and low-cost ion exchange process. The effects of ion exchange time and temperature on the physicochemical properties and photocatalytic activities of the composite microspheres were studied through photocatalytic degradation of Acid Orange II under xenon lamp irradiation. The obtained samples were analyzed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, UV-vis diffuse reflectance spectroscopy, N2 physical adsorption, and photocurrent tests. The CaMg(CO3)2@Ag2CO3 sample with the highest activity was obtained with an ion exchange time of 4 h and temperature of 40 °C. The degradation rate of Acid Orange II by this sample reached 83.3% after 15 min of light irradiation, and the sample also performed well in phenol degradation. The CaMg(CO3)2@Ag2CO3 produced under these ion exchange conditions showed a well-ordered hierarchical morphology with small particle sizes, which was beneficial to light absorption and the transfer of photoelectrons (e−) and holes (h+) to the catalyst surface. Moreover, the separation of photogenerated·carriers over the composites was greatly improved relative to bare CaMg(CO3)2. Despite the very low content of Ag2CO3 (2.56%), excellent photocatalytic performance was obtained over the CaMg(CO3)2@Ag2CO3 microspheres.
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      PubDate: 2017-12-13T11:36:09Z
       
  • Carbon film encapsulated Fe2O3: An efficient catalyst for hydrogenation of
           nitroarenes
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): Yingyu Wang, Juanjuan Shi, Zihao Zhang, Jie Fu, Xiuyang Lü, Zhaoyin Hou
      Iron catalysis has attracted a wealth of interdependent research for its abundance, low price, and nontoxicity. Herein, a convenient and stable iron oxide (Fe2O3)-based catalyst, in which active Fe2O3 nanoparticles (NPs) were embedded into carbon films, was prepared via the pyrolysis of iron-polyaniline complexes on carbon particles. The obtained catalyst shows a large surface area, uniform pore channel distribution, with the Fe2O3 NPs homogeneously dispersed across the hybrid material. Scanning electron microscopy, Raman spectroscopy and X-ray diffraction analyses of the catalyst prepared at 900 °C (Fe2O3@G-C-900) and an acid-pretreated commercial activated carbon confirmed that additional carbon materials formed on the pristine carbon particles. Observation of high-resolution transmission electron microscopy images also revealed that the Fe2O3 NPs in the hybrid were encapsulated by a thin carbon film. The Fe2O3@G-C-900 composite was highly active and stable for the direct selective hydrogenation of nitroarenes to anilines under mild conditions, where previously noble metals were required. The synthetic strategy and the structure of the iron oxide-based composite may lead to the advancement of cost-effective and sustainable industrial processes.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Environmentally friendly, microwave-assisted synthesis of 5-substituted 1
           H-tetrazoles by recyclable CuO nanoparticles via (3+2) cycloaddition of
           nitriles and NaN3
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): R.D. Padmaja, Sourav Rej, Kaushik Chanda
      Recyclable CuO nanoparticles were successfully employed to catalyze the microwave-assisted (3+2) cycloaddition reaction between nitriles and NaN3 to efficiently synthesize 5-substituted 1H-tetrazoles. The salient features associated with this protocol are its cost effectiveness, rapid synthesis, stability, reusability, mild reaction conditions without any additives, high tolerance to various functional groups, and excellent yields under microwave irradiation. This environmentally friendly, microwave-assisted, nanoparticle-catalyzed synthetic methodology is seen as an alternative to conventional procedures that involve Lewis acid catalysts and a simple operation to the privileged scaffold.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Effects of surface physicochemical properties on NH3-SCR activity of MnO2
           catalysts with different crystal structures
    • Abstract: Publication date: November 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 11
      Author(s): PiJun Gong, JunLin Xie, De Fang, Da Han, Feng He, FengXiang Li, Kai Qi
      α-, β-, δ-, and γ-MnO2 nanocrystals are successfully prepared. We then evaluated the NH3 selective catalytic reduction (SCR) performance of the MnO2 catalysts with different phases. The NO x conversion efficiency decreased in the order: γ-MnO2 > α-MnO2 > δ-MnO2 > β-MnO2. The NO x conversion with the use of γ-MnO2 and α-MnO2 catalysts reached 90% in the temperature range of 140–200 °C, while that based on β-MnO2 reached only 40% at 200 °C. The γ-MnO2 and α-MnO2 nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area. We found that γ-MnO2 and α-MnO2 possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts. In addition, more chemisorbed oxygen existed on the surface of the γ-MnO2 and α-MnO2 catalysts. The γ-MnO2 and α-MnO2 catalysts showed excellent performance in the low-temperature SCR of NO to N2 with NH3.
      Graphical abstract image

      PubDate: 2017-12-13T11:36:09Z
       
  • Titanocene dichloride: A new green reagent in organic chemistry
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Antonio Rosales Martínez, María Castro Rodríguez, Ignacio Rodríguez-García, Laura Pozo Morales, Roman Nicolay Rodríguez Maecker
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Direct construction of sulfenylated pyrazoles catalyzed by I2 at room
           temperature
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Shuang-Hong Hao, Li-Xia Li, Dao-Qing Dong, Zu-Li Wang
      An iodine-catalyzed sulfenylation of pyrazoles at room temperature is described, in which a variety of pyrazoles were well tolerated and the desired products were obtained in good to excellent yields.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • High performance ORR electrocatalysts prepared via one-step pyrolysis of
           riboflavin
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Yuxiao Deng, Haixin Huangfu, Shuihua Tang, Jie Li
      Efficient, cost-effective electrocatalysts for an oxygen reduction reaction (ORR) are currently required for fuel cells. In the present work, riboflavin was used as a cheap, nontoxic carbon and nitrogen precursor to prepare Fe–N–C catalysts via one-step pyrolysis in the presence of anhydrous iron chloride. Raman spectroscopy indicated that the catalyst containing nitrogen created a great quantity of defects in the carbon structures, while nitrogen adsorption-desorption isotherms showed that the catalyst was mesoporous. Transmission electron microscopy demonstrated that the Fe–N–C catalyst was composed of very thin, curved and porous graphene layers together with some Fe2O3 nanoparticles, and X-ray diffraction patterns confirmed that the carbon in the catalyst was highly graphitized. X-ray photoelectron spectroscopy indicated that the active sites for the ORR were primarily composed of graphitic nitrogen, although Fe sites also played an important role. The ORR activity of the Fe–N–C catalyst reached a maximum of 4.16 mA cm−2, and its chronoamperometric response was found to decrease by only 3% after operating for 3 h at 0.66 V (vs RHE) in an O2-saturated 0.1 mol L−1 KOH solution. In contrast, a commercial 40 wt% Pt/C catalyst with a loading of 0.2 mgPt cm−2 exhibited an activity of 4.46 mA cm−2 and a 40% loss of response. The electrochemical performance of this new Fe–N–C catalyst was therefore comparable to that of the Pt/C catalyst while showing significantly better stability.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Catalytic performance and synthesis of a Pt/graphene-TiO2 catalyst using
           an environmentally friendly microwave-assisted solvothermal method
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Min Wang, Zhongwei Wang, Lu Wei, Jianwei Li, Xinsheng Zhao
      A Pt/graphene-TiO2 catalyst was prepared by a microwave-assisted solvothermal method and was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, and linear sweep voltammetry. The cubic TiO2 particles were approximately 60 nm in size and were distributed on the graphene sheets. The Pt nanoparticles were uniformly distributed between the TiO2 particles and the graphene sheet. The catalyst exhibited a significant improvement in activity and stability towards the oxygen reduction reaction compared with Pt/C, which resulted from the high electronic conductivity of graphene and strong metal-support interactions.
      Graphical abstract image

      PubDate: 2017-11-02T03:21:47Z
       
  • Influence of carbon and yttrium co-doping on the photocatalytic activity
           of mixed phase TiO2
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Honglin Gao, Jianmei Liu, Jin Zhang, Zhongqi Zhu, Genlin Zhang, Qingju Liu
      Mixed phase TiO2 photocatalysts doped with C and Y were synthesized by a sol-gel process. The effects of C and Y doping and annealing temperatures on the structural and optical properties, and photocatalytic activity were investigated. We found that both C and Y doping can broaden the absorption spectrum of TiO2 to the visible light region and inhibit recombination of photogenerated electron/hole pairs. The incorporation of Y into the TiO2 lattice inhibited growth of crystalline grains, which increased the specific surface area and enhanced the photocatalytic activity. The photocatalytic performance of the samples was investigated in the photocatalytic degradation of methyl blue under visible light irradiation. The rate of methyl blue degradation over the (C, Y)-co-doped TiO2 sample was much higher than those of undoped TiO2, C-TiO2, and Y-TiO2. Additionally, the apparent first-order rate constant of the co-doped sample was 3.5 times as large as that of undoped mix phase TiO2 under the same experimental conditions. The enhanced photocatalytic activity can be attributed to the synergic effect of (C, Y)-co-doping and the formation of an appropriate crystalline structure.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Coke-tolerant SiW20-Al/Zr10 catalyst for glycerol dehydration to acrolein
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Amin Talebian-Kiakalaieh, Nor Aishah Saidina Amin
      Glycerol dehydration to acrolein over a series of supported silicotungstic acid catalysts (SiW x -Al/Zr y ) was investigated. Characterization results showed that the final catalyst had high thermal stability, a large pore diameter, strong Lewis acidic sites, and a large specific surface area. X-ray photoelectron survey spectra clearly showed peaks attributable to W (W 4f = 35.8 eV), Al2O3 (Al 2p = 74.9 eV), and ZrO2 (Zr 3d = 182.8 eV). The highest acrolein selectivity achieved was 87.3% at 97% glycerol conversion over the SiW20-Al/Zr10 catalyst. The prepared catalysts were highly active and selective for acrolein formation even after 40 h because of the presence of high concentrations of Lewis acidic sites, which significantly reduced the amount of coke on the catalyst surface. Response surface methodology optimization showed that 87.7% acrolein selectivity at 97.0% glycerol conversion could be obtained under the following optimal reaction conditions: 0.5 wt% catalyst, reaction temperature 300 °C, and feed glycerol concentration 10 wt%. Evaluation of a mass-transfer-limited regime showed the absence of internal and external diffusions over pellets of diameter d P < 20 μm. These results show that glycerol dehydration over a strong Lewis acid catalyst is a promising method for acrolein production.
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      PubDate: 2017-11-02T03:21:47Z
       
  • One-step synthesis of graphitic carbon nitride nanosheets for efficient
           catalysis of phenol removal under visible light
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Wang Ding, Suqin Liu, Zhen He
      Graphitic carbon nitride (g-C3N4) nanosheet photocatalysts were synthesized via a facile impregnation-thermal method. The as-prepared materials were characterized and investigated as metal-free photocatalysts for the degradation of phenol in aqueous solution under visible light. Results revealed that the g-C3N4 nanosheets exhibited a 78.9% degradation for phenol after 30 min, which was much faster than that of the pristine g-C3N4. Using Brunauer-Emmett-Teller theory, the surface area of g-C3N4 nanosheets was 103.24 m2/g, which was much larger than that of g-C3N4. The larger surface area increases the contact area of the material with phenol, enhancing the photocatalytic activity. These results highlight the potential application of sustainable metal-free photocatalysts in water purification.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Novel-structured Mo-Cu-Fe-O composite for catalytic air oxidation of
           dye-containing wastewater under ambient temperature and pressure
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Yin Xu, Henan Shao, Fei Ge, Yun Liu
      A novel-structured Mo-Cu-Fe-O composite was successfully prepared by co-precipitation and impregnation method. The properties of the as-prepared samples were determined using X-ray diffraction, temperature-programmed reduction by H2, cyclic voltammetry, and temperature-programmed desorption by O2. The results showed that Mo6+ diffused into the Cu-Fe-O crystal lattice and then formed a new crystalline phase of CuMoO4. The Mo-Cu-Fe-O catalyst had redox properties, and its surface contained active sites for oxygen adsorption. In addition, the catalytic activity of the Mo-Cu-Fe-O composite was evaluated by the degradation of Cationic Red GTL, Crystal Violet, and Acid Red in catalytic wet air oxidation (CWAO) at ambient temperature and pressure. The Mo-Cu-Fe-O catalyst showed excellent activity at basic conditions for the degradation of Cationic Red GTL. High removal efficiencies of 91.5% and 92.8% were achieved for Cationic Red GTL and Crystal Violet, respectively, in wastewater, and the efficiency remained high after seven cycles. However, almost no degradation of Acid Red occurred in the CWAO process. Furthermore, hydroxyl radicals were formed in the CWAO process, which induced the decomposition of the two cationic dyes in wastewater, and the toxicity of their effluents was decreased after degradation. The results indicate that the Mo-Cu-Fe-O composite shows excellent catalytic activity for the treatment of wastewater contaminated with cationic dyes.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Synthesis of Ag/AgCl/Fe-S plasmonic catalyst for bisphenol A degradation
           in heterogeneous photo-Fenton system under visible light irradiation
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Yun Liu, Yanyan Mao, Xiaoxiao Tang, Yin Xu, Chengcheng Li, Feng Li
      A novel plasmonic photo-Fenton catalyst of Ag/AgCl/Fe-S was synthesized by ion exchange and photoreduction methods. The obtained catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope imaging, and Brunauer-Emmett-Teller measurements. Moreover, the photocatalytic activity of Ag/AgCl/Fe-S was investigated for its degradation activity towards bisphenol A (BPA) as target pollutant under visible light irradiation. The effects of H2O2 concentration, pH value, illumination intensity, and catalyst dosage on BPA degradation were examined. Our results indicated that the Ag/AgCl material was successfully loaded onto Fe-sepiolite and showed a high photocatalytic activity under illumination by visible light. Furthermore, active species capture experiments were performed to explore the photocatalytic mechanism of the Ag/AgCl/Fe-S in this heterogeneous photo-Fenton process, where the major active species included hydroxyl radicals (•OH) and holes (h+).
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      PubDate: 2017-11-02T03:21:47Z
       
  • Influence of nickel(II) oxide surface magnetism on molecule adsorption: A
           first-principles study
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Chuan-Qi Huang, Wei-Xue Li
      The influence of the magnetism of transition metal oxide, nickel(II) oxide (NiO), on its surface reactivity and the dependence of surface reactivity on surface orientation and reactant magnetism were studied by density functional theory plus U calculations. We considered five different antiferromagnetically ordered structures and one ferromagnetically ordered structure, NiO(001) and Ni(011) surfaces, paramagnetic molecule NO, and nonparamagnetic molecule CO. The calculations showed that the dependence of surface energies on magnetism was modest, ranging from 49 to 54 meV/Å2 for NiO(001) and from 162 to 172 meV/Å2 for NiO(011). On NiO(001), both molecules preferred the top site of the Ni cation exclusively for all NiO magnetic structures considered, and calculated adsorption energies ranged from –0.33 to –0.37 eV for CO and from –0.42 to –0.46 eV for NO. On NiO(011), both molecules preferred the bridge site of two Ni cations irrespective of the NiO magnetism. It was found that rather than the long-range magnetism of bulk NiO, the local magnetic order of two coordinated Ni cations binding to the adsorbed molecule had a pronounced influence on adsorption. The calculated NO adsorption energy at the (↑↓) bridge sites ranged from –0.99 to –1.05 eV, and become stronger at the (↑↑) bridge sites with values of –1.21 to –1.30 eV. For CO, although the calculated adsorption energies at the (↑↓) bridge sites (–0.73 to –0.75 eV) were very close to those at the (↑↑) bridge sites (–0.71 to –0.72 eV), their electron hybridizations were very different. The present work highlights the importance of the local magnetic order of transition metal oxides on molecular adsorption at multi-fold sites.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Catalytic performance of highly dispersed WO3 loaded on CeO2 in the
           selective catalytic reduction of NO by NH3
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Lei Zhang, Jingfang Sun, Yan Xiong, Xiaoqing Zeng, Changjin Tang, Lin Dong
      The influence of tungsten trioxide (WO3) loading on the selective catalytic reduction (SCR) of nitric oxide (NO) by ammonia (NH3) over WO3/cerium dioxide (CeO2) was investigated. The NO conversion first rose and then declined with increasing WO3 loading. It was found that the crystalline WO3 in the 1.6WO3/CeO2 sample could be removed in 25 wt% ammonium hydroxide at 70 °C, which improved the catalytic activity of the sample. The obtained samples were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, hydrogen (H2) temperature programmed reduction, NH3 temperature programmed desorption, and in situ diffuse reflectance infrared Fourier transform spectroscopy. The results revealed that the dispersed WO3 promoted the catalytic activity of WO3/CeO2 while the crystalline WO3 inhibited catalytic activity. The oxygen activation of CeO2 was inhibited by the coverage of WO3, which weakened NO oxidation and adsorption of nitrate species over WO3/CeO2. In addition, the NH3 adsorption performance on CeO2 was improved by modification with WO3. NH3 was the most stable adsorbed species under NH3 SCR reaction conditions. In situ DRIFT spectra suggested that the NH3 SCR reaction proceeded via the Eley-Rideal mechanism over WO3/CeO2. Thus, when the loading of WO3 was close to the dispersion capacity, the effects of NH3 adsorption and activation were maximized to promote the reaction via the Eley-Rideal route.
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      PubDate: 2017-11-02T03:21:47Z
       
  • A novel process of ozone catalytic oxidation for low concentration
           formaldehyde removal
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Bin Zhu, Xiao-Song Li, Peng Sun, Jing-Lin Liu, Xiao-Yuan Ma, Xiaobing Zhu, Ai-Min Zhu
      To reduce energy costs, minimize secondary pollution from undecomposed ozone, and improve the efficiency of ozone use, a novel process of cycled storage-ozone catalytic oxidation (OZCO) was employed to remove formaldehyde (HCHO) at low concentrations in air. We applied Al2O3-supported manganese oxide (MnO x ) catalysts to this process, and examined the HCHO adsorption capacity and OZCO performance over the MnO x catalysts. Owing to the high dispersion of MnO x and low oxidation state of manganese, the MnO x /Al2O3 catalysts with a manganese acetate precursor and 10%-Mn loading showed good performance in both storage and OZCO stages. The presence of H2O led to a decrease of the HCHO adsorption capacity owing to competitive adsorption between moisture and HCHO at the storage stage; however, high relative humidity (RH) favored complete conversion of stored HCHO to CO2 at the OZCO stage and contributed to an excellent carbon balance. Four low concentration HCHO storage-OZCO cycles with a long HCHO storage period and relatively short OZCO period were successfully performed over the selected MnO x /Al2O3 catalyst at room temperature and a RH of 50%, demonstrating that the proposed storage-OZCO process is an economical, reliable, and promising technique for indoor air purification.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Visible light-responsive carbon-decorated p-type semiconductor CaFe2O4
           nanorod photocatalyst for efficient remediation of organic pollutants
    • Abstract: Publication date: October 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 10
      Author(s): Xin Liu, Yuhong Zhang, Yushuai Jia, Junzhe Jiang, Yabin Wang, Xiangshu Chen, Tian Gui
      We report the fabrication and photocatalytic property of a composite of C/CaFe2O4 nanorods (NRs) in an effort to reveal the influence of carbon modification. It is demonstrated that the photocatalytic degradation activity is dependent on the mass ratio of C to CaFe2O4. The optimal carbon content is determined to be 58 wt% to yield a methylene blue (MB) degradation rate of 0.0058 min−1, which is 4.8 times higher than that of the pristine CaFe2O4 NRs. The decoration of carbon on the surface of CaFe2O4 NRs improves its adsorption capacity of the MB dye, which is specifically adsorbed on the surface as a monolayer according to the adsorption isotherm analysis. The trapping experiments of the reactive species indicate that superoxide radicals (•O2 −) are the main active species responsible for the removal of MB under visible-light irradiation. Overall, the unique feature of carbon coating enables the efficient separation and transfer of photogenerated electrons and holes, strengthens the adsorption capacity of MB, and improves the light harvesting capability, hence enhancing the overall photocatalytic degradation of MB.
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      PubDate: 2017-11-02T03:21:47Z
       
  • Preface to the Special Issue of the International Symposium on Single-Atom
           Catalysis (ISSAC-2016)
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Jun Li, Jimmy Liu, Tao Zhang
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Supported metal catalysts at the single-atom limit – A viewpoint
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Maria Flytzani-Stephanopoulos
      An account of recent work on supported single-atom catalyst design is given here for reactions as diverse as the low-temperature water-gas shift, methanol steam reforming, selective ethanol dehydrogenation, and selective hydrogenation of alkynes and dienes. It is of fundamental interest to investigate the intrinsic activity and selectivity of the active metal atom site and compare them to the properties of the corresponding metal nanoparticles and sub-nm clusters. It is also important to understand what constitutes a stable active metal atom site in the various reaction environments, and maximize their loadings to allow us to design robust catalysts for industrial applications. Combined activity and stability studies, ideally following the evolution of the active site as a function of catalyst treatment in real time are recommended. Advanced characterization methods with atomic resolution will play a key role here and will be used to guide the design of new catalysts.
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      PubDate: 2017-09-19T22:38:39Z
       
  • Two-dimensional materials confining single atoms for catalysis
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Yong Wang, Wenhua Zhang, Dehui Deng, Xinhe Bao
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Unravelling single atom catalysis: The surface science approach
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Gareth S. Parkinson
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      PubDate: 2017-09-19T22:38:39Z
       
  • Aberration-corrected scanning transmission electron microscopy in
           single-atom catalysis: Probing the catalytically active centers
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Jingyue Liu
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Using probe molecule FTIR spectroscopy to identify and characterize
           Pt-group metal based single atom catalysts
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Chithra Asokan, Leo DeRita, Phillip Christopher
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      PubDate: 2017-09-19T22:38:39Z
       
  • X-ray absorption spectroscopy for single-atom catalysts: Critical
           importance and persistent challenges
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Isao Ogino
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      PubDate: 2017-09-19T22:38:39Z
       
  • Increasing the range of non-noble-metal single-atom catalysts
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Ting Deng, Weitao Zheng, Wei Zhang
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      PubDate: 2017-09-19T22:38:39Z
       
  • Single atom catalyst by atomic layer deposition technique
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Niancai Cheng, Xueliang Sun
      Noble single-atom catalysts have rapidly been attracting attention due to their unique catalytic properties and maximized utilization. Atomic layer deposition (ALD) is an emerging powerful technique for large-scale synthesis of stable single atom. In this review, we summarize recent developments of single atom synthesized by ALD as well as explore future research direction and trends.
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      PubDate: 2017-09-19T22:38:39Z
       
  • Metal-mediated catalysis in the gas phase: A review
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Xiao-Na Li, Xiu-Ping Zou, Sheng-Gui He
      This review summarizes a variety of experimentally identified gas-phase catalytic cycles, all of which are mediated by atomic metal ions, bare metal clusters, metal oxide clusters or metal complexes. Emphasis is placed on the latest advances in the unique catalytic reactivity of cluster-confined single noble metal atoms. The cycles discussed in this paper cover a wide range of inorganic and organic molecules. The use of start-of-the-art mass spectrometric instrumentation in conjunction with quantum chemistry calculations is also reported, as these techniques have determined the mechanistic details of the elementary steps of such catalytic cycles. The important role of gas-phase data in guiding the rational design of better-performing catalysts in related condensed phase reactions is also examined. In particular, this review focuses on the following three topics: (1) the catalytic oxidation of carbon monoxide, (2) the catalytic functionalization of methane, and (3) catalytic decarboxylation.
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      PubDate: 2017-09-19T22:38:39Z
       
  • Preparation, characterization and catalytic performance of single-atom
           catalysts
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Liqiong Wang, Liang Huang, Feng Liang, Simin Liu, Yuhua Wang, Haijun Zhang
      Supported and colloidal single-atom catalysts (SACs), which possess excellent catalytic properties, are particularly important in both fundamental studies and practical applications. The progress made in the preparation methods, characterization, catalytic performances and mechanisms of SACs anchored to metal oxides, two-dimensional materials and the surface of metal nanoclusters (NCs) are reviewed. The different techniques for SAC fabrication, including conventional solution methods based on co-precipitation, incipient wetness co-impregnation, and the chemical vapor deposition method, as well as the newer atom layer deposition (ALD) and galvanic replacement methods, are summarized. The main results from experimental and theoretical studies of various catalytic reactions over SACs, including oxidation reactions, hydrogenation, water gas shift, photocatalytic H2 evolution and electrochemical reactions, are also discussed. Moreover, the electronic properties of the single atoms and their interactions with the supports are described to assist in understanding the origin of the high catalytic activity and selectivity of SACs. Finally, possible future research directions of SACs and their applications are proposed.
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      PubDate: 2017-09-19T22:38:39Z
       
  • Isolation of Pd atoms by Cu for semi-hydrogenation of acetylene: Effects
           of Cu loading
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Guangxian Pei, Xiaoyan Liu, Mengqian Chai, Aiqin Wang, Tao Zhang
      Cu-alloyed Pd single-atom catalysts exhibit excellent catalytic performance for the semi-hydrogenation of acetylene; however, the limit of the Cu/Pd atomic ratio for forming the alloyed Pd single-atom catalyst is ambiguous. Herein, silica-supported Cu–Pd bimetallic catalysts with fixed Pd content and varied Cu loadings were synthesized using an incipient wetness co-impregnation method. The X-ray absorption spectroscopy results indicated that Pd formed an alloy with Cu after reduction at 250 °C and that the Pd atoms were completely isolated by Cu for Cu/Pd atomic ratios ≥ 40/1. Notably, increasing the reduction temperature from 250 to 400 °C hardly affected the catalytic performances of the Cu–Pd/SiO2 catalysts. This finding can be attributed to the similar chemical environments of Pd demonstrated by the X-ray absorption spectroscopy results.
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      PubDate: 2017-09-19T22:38:39Z
       
  • Probing the catalytic behavior of ZnO nanowire supported Pd1 single-atom
           catalyst for selected reactions
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Jia Xu, Yian Song, Honglu Wu, Jingyue Liu
      We have dispersed individual Pd atoms onto ZnO nanowires (NWs) as single-atom catalysts (SACs) and evaluated their catalytic performance for several selected catalytic reactions. The Pd1/ZnO SAC is highly active, stable, and selective towards CO2 for steam reforming of methanol to produce hydrogen. This catalyst system is active for oxidation of CO and H2 but performs poorly for preferential oxidation of CO in hydrogen-rich stream primarily due to the strong competitive oxidation of H2 on ZnO supported Pd1 atoms. At ambient pressure, reverse water-gas-shift reaction occurs on the Pd1/ZnO SAC. This series of tests of catalytic reactions clearly demonstrate the importance of selecting the appropriate metal and support to develop SACs for catalytic transformation of molecules.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Investigation of water adsorption and dissociation on Au1/CeO2 single-atom
           catalysts using density functional theory
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Yan Tang, Yang-Gang Wang, Jin-Xia Liang, Jun Li
      We examined the water adsorption and dissociation on ceria surfaces as well as ceria-supported Au single-atom catalysts using density functional theory calculations. Molecular and dissociative water were observed to coexist on clean CeO2 and reduced Au1/CeO2−x surfaces because of the small difference in adsorption energies, whereas the presence of dissociative water was highly favorable on reduced CeO2−x and clean Au1/CeO2 surfaces. Positively charged Au single atoms on the ceria surface not only provided activation sites for water adsorption but also facilitated water dissociation by weakening the intramolecular O–H bonds. In contrast, negatively charged Au single atoms were not reactive for water adsorption because of the saturation of Au 5d and 6s electron shells. This work provides a fundamental understanding of the interaction between water and single-atom Au catalysts.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Catalytic ativities of single-atom catalysts for CO oxidation: Pt1/FeOx
           vs. Fe1/FeOx
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Jinxia Liang, Xiaofeng Yang, Congqiao Xu, Tao Zhang, Jun Li
      An FeO x -based Pt single-atom catalyst (SAC), Pt1/FeO x , has stimulated significant recent interest owing to its extraordinary activity toward CO oxidation. The concept of SAC has also been successfully extended to other FeO x supported transition metal systems both experimentally and theoretically. However, the FeO x substrate itself (denoted by Fe1/FeO x following the same nomenclature of Pt1/FeO x ) as a typical transition metal oxide possesses a very low catalytic activity toward CO oxidation, although it can be viewed as Fe1/FeO x SAC. Here, to understand the catalytic mechanism of FeO x -based SACs for CO oxidation, we have performed density functional theory calculations on Pt1/FeO x and Fe1/FeO x for CO oxidation to address the differences between these two SACs in terms of the catalytic mechanism of CO oxidation and the chemical behavior of the catalysts. Our calculation results indicated that the catalytic cycle of Fe1/FeO x is much more difficult to accomplish than that of SAC Pt1/FeO x because of a high activation barrier (1.09 eV) for regeneration of the oxygen vacancy formed when the second CO2 molecule desorbs from the surface. Moreover, density of states and Bader charge analysis revealed differences in the catalytic performance for CO oxidation by the SACs Fe1/FeO x and Pt1/FeO x . This work provides insights into the fundamental interactions between the single-atom Pt1 and FeO x substrate, and the exceptional catalytic performance of this system for CO oxidation.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Photochemical route for preparing atomically dispersed Pd1/TiO2 catalysts
           on (001)-exposed anatase nanocrystals and P25
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Pengxin Liu, Jie Chen, Nanfeng Zheng
      Atomically dispersed catalysts have shown promising prospects in catalysis studies. Among all of the developed methods for synthesizing atomically dispersed catalysts, the photochemical approach has recently aroused much attention owing to its simple procedure and mild preparation conditions involved. In the present study, we demonstrate the application of the photochemical method to synthesize atomically dispersed Pd catalysts on (001)-exposed anatase nanocrystals and commercial TiO2 (P25). The as-prepared catalysts exhibit both high activity and stability in the hydrogenation of styrene and catalytic oxidation of CO.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Coating Pd/Al2O3 catalysts with FeOx enhances both activity and
           selectivity in 1,3-butadiene hydrogenation
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Hong Yi, Yujia Xia, Huan Yan, Junling Lu
      Pd-based catalysts are widely used in hydrogenation reactions, and it is essential to improve the selectivity of these catalysts to give the desired products, especially at high conversions. However, improvements in selectivity have generally been achieved at the expense of catalytic activity. Here, we report that deposition of FeO x onto a Pd/Al2O3 catalyst using atomic layer deposition with precise, near atomic control provides a remarkable improvement in both activity and butene selectivity in the selective hydrogenation of 1,3-butadiene under mild conditions. Diffuse reflectance infrared Fourier transform spectroscopy for CO chemisorption measurements illustrate that FeO x preferentially nucleates on Pd (111) facets and divides the Pd surface atoms into small ensembles. X-ray photoelectron spectroscopy measurements revealed that the Pd became electron deficient after FeO x deposition owing to the strong Pd–FeO x interaction. Our results suggest that a geometric effect, that is, the formation of small Pd ensembles, is the main contributor to the improvement in butene selectivity, whereas the enhancement in hydrogenation activity may be attributed to both electronic effects and the newly generated Pd–FeO x interface.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Top-down synthesis strategies: Maximum noble-metal atom efficiency in
           catalytic materials
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Yaxin Chen, Zhiwei Huang, Xiao Gu, Zhen Ma, Jianmin Chen, Xingfu Tang
      Top-down synthesis has been used to prepare catalytic materials with nanometer sizes, but fabricating atomically dispersed metal catalysts remains a challenge because surface single metal atoms are prone to aggregation or coalescence. A top-down strategy is used to synthesize atomically dispersed metal catalysts, based on supported Ag nanoparticles. The changes of the geometric and electronic structures of the Ag atoms during the top-down process are studied using the in situ synchrotron X-ray diffraction technique, ex situ X-ray absorption spectroscopy, and transmission electron microscopy. The experimental results, coupled with the density functional theory calculations, demonstrate that the electronic perturbation of the Ag frontier orbitals, induced by the Ag-O interactions at the perimeter of the metal-support interface, is the driving force of the top-down process. The top-down synthesis has two important functions: to increase the number of catalytic active sites and to facilitate the study of complex reaction mechanisms (e.g., formaldehyde oxidation) by developing single-site model catalysts.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
  • Identification of active sites for hydrogenation over Ru/SBA-15 using in
           situ Fourier-transform infrared spectroscopy
    • Abstract: Publication date: September 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 9
      Author(s): Hangjia Shen, Xianyuan Wu, Dahao Jiang, Xiaonian Li, Jun Ni
      The active sites for hydrogenation over Ru/SBA-15 catalysts were identified using in situ Fourier-transform infrared spectroscopy. The amount of active sites was proportional to the interfacial circumference of the Ru particles. In contrast, the rate of hydrogen spillover from Ru to the support was inversely proportional to the size of the Ru metal particles. Consequently, a catalyst with small Ru metal particles has a high rate of hydrogen spillover but a low density of active sites, whereas one with large Ru particles has a low rate of hydrogen spillover but a high density of active sites. The formation of these active sites is probably an intermediate step in hydrogen spillover.
      Graphical abstract image

      PubDate: 2017-09-19T22:38:39Z
       
 
 
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