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  Subjects -> ENGINEERING (Total: 2269 journals)
    - CHEMICAL ENGINEERING (190 journals)
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    - ENGINEERING (1201 journals)
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ENGINEERING (1201 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 14)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 207)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 4)
Advanced Science     Open Access   (Followers: 4)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 4)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 6)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Artificial Neural Systems     Open Access   (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 Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
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Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
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Advances in Remote Sensing     Open Access   (Followers: 34)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 28)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access  
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 5)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 6)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 4)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal  
ASEE Prism     Full-text available via subscription   (Followers: 2)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 7)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 9)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 3)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 24)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 8)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 40)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 4)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 10)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 13)
City, Culture and Society     Hybrid Journal   (Followers: 20)
Clay Minerals     Full-text available via subscription   (Followers: 8)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 4)
Coastal Engineering     Hybrid Journal   (Followers: 10)
Coastal Engineering Journal     Hybrid Journal   (Followers: 3)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 23)
Composite Interfaces     Hybrid Journal   (Followers: 5)
Composite Structures     Hybrid Journal   (Followers: 242)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 175)
Composites Part B : Engineering     Hybrid Journal   (Followers: 215)
Composites Science and Technology     Hybrid Journal   (Followers: 159)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 25)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 7)
Control Engineering Practice     Hybrid Journal   (Followers: 40)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 7 | Last

Journal Cover Chinese Journal of Catalysis
  [SJR: 0.6]   [H-I: 29]   [2 followers]  Follow
    
   Full-text available via subscription Subscription journal  (Not entitled to full-text)
   ISSN (Print) 1872-2067
   Published by Elsevier Homepage  [3041 journals]
  • Preface to Special Issue on the International Symposium on Environmental
           Catalysis (ISEC 2016)
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Jinlin Li, Jiaguo Yu


      PubDate: 2017-03-13T00:21:57Z
       
  • Photochemical oxidation mechanism of microcystin-RR by p-n heterojunction
           Ag/Ag2O-BiVO4
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Chunhong Wu, Yanfen Fang, Araya Hailu Tirusew, Miaomiao Xiang, Yingping Huang, Chuncheng Chen
      Microcystin-RR (MC-RR), a form of microcystin with two arginine moieties, is a cyanobacterial toxin that has been detected across a wide geographic range. It is a great concern globally because of its potential liver toxicity. Herein, the abilities of BiVO4, Ag-BiVO4, Ag2O-BiVO4 and Ag/Ag2O-BiVO4 to photocatalytically degrade MC-RR under visible-light irradiation (λ ≥ 420 nm) were investigated and compared. The possible degradation pathways were explored through analysis of the reaction intermediates by high-performance liquid chromatography-mass spectrometry. The results showed that the presence of Ag0 enhanced the photocatalytic efficiency of Ag/Ag2O-BiVO4 via a synergetic effect between Ag2O and Ag0 at the p-n heterojunction. Moreover, the presence of Ag0 also greatly promoted the adsorption of MC-RR on the photocatalyst surface. Toxicological experiments on mice showed that the toxicity of MC-RR was significantly reduced after photocatalytic degradation.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Effects of hierarchical structure on the performance of tin
           oxide-supported platinum catalyst for room-temperature formaldehyde
           oxidation
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Yuanyuan Duan, Shaoqing Song, Bei Cheng, Jiaguo Yu, Chuanjia Jiang
      Flower-like tin oxide-supported platinum (Pt/SnO x ) with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD, SEM, TEM, high resolution TEM, XPS and nitrogen adsorption. The flower-like Pt/SnO x microspheres of 1 μm in diameter were composed of staggered petal-like nanosheets with a thickness of 20 nm. Pt nanoparticles (NPs) of 2–3 nm were well dispersed on the SnO x nanosheets. The catalyst was tested in the catalytic oxidation of gaseous formaldehyde (HCHO) at room temperature, and exhibited enhanced activity compared to Pt NPs supported on commercial SnO and ground SnO x . HCHO removal of 87% was achieved over the hierarchical Pt/SnO x after 1 h of reaction, which was 1.5 times that over the ground SnO x -supported Pt (Pt/g-SnO x ), and the high activity was maintained after six recycles, showing the high stability of this catalyst. HCHO decomposition kinetics was modeled as a second order reaction. The reaction rate constant for Pt/SnO x was 5.6 times higher than Pt/g-SnO x . The hierarchical pore structure was beneficial for the diffusion and adsorption of HCHO molecules, and the highly dispersed Pt NPs on the SnO x nanosheets were the active sites for the oxidative decomposition of HCHO into CO2 and H2O. This study provided a promising approach for designing efficient catalysts for indoor HCHO removal at ambient temperature.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Catalytic performance of cobalt oxide-supported gold-palladium
           nanocatalysts for the removal of toluene and o-xylene
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Zhiwei Wang, Yuxi Liu, Tao Yang, Jiguang Deng, Shaohua Xie, Hongxing Dai
      Using the molten salt and polyvinyl alcohol-protected reduction method, we fabricated Co3O4 octahedron-supported Au-Pd (x(AuPd y )/Co3O4; x = (0.18, 0.47, and 0.96) wt%; y (Pd/Au molar ratio) = 1.85−1.97) nanocatalysts. The molten salt-derived Co3O4 sample possessed well-defined octahedral morphology, with an edge length of 300 nm. The Au-Pd nanoparticles, with sizes of 2.7−3.2 nm, were uniformly dispersed on the surface of Co3O4. The 0.96 (AuPd1.92)/Co3O4 sample showed the highest catalytic activity for toluene and o-xylene oxidation, and the temperature required for achieving 90% conversion of toluene and o-xylene was 180 and 187 °C, respectively, at a space velocity of 40000 mL/(g–h). The high catalytic performance of Co3O4 octahedron-supported Au-Pd nanocatalysts was associated with the interaction between Au-Pd nanoparticles and Co3O4 and high concentration of adsorbed oxygen species.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Heterostructured BiOI@La(OH)3 nanorods with enhanced visible light
           photocatalytic NO removal
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Yanjuan Sun, Xiang Xiao, Xing'an Dong, Fan Dong, Wei Zhang
      Heterostructured BiOI@La(OH)3 nanorod photocatalysts were prepared by a facile chemical impregnation method. The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La(OH)3 nanorods. The BiOI@La(OH)3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La(OH)3 nanorods. The results show that the energy levels between the La(OH)3 and BiOI phases matched well with each other, thus forming a heterojunctioned BiOI@La(OH)3 structure. This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface, resulting in enhanced photocatalytic performance under visible light irradiation. The photocatalytic performance of BiOI@La(OH)3 is shown to be dependent on the mass ratio of BiOI to La(OH)3. The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La(OH)3 is controlled at 1.5. A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers. A new photocatalytic mechanism for BiOI@La(OH)3 heterostructures is proposed, which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction. Importantly, the as-prepared BiOI@La(OH)3 heterostructures exhibited a high photochemical stability after multiple reaction runs. Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor, which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Heterogeneous catalytic activation of peroxymonosulfate for efficient
           degradation of organic pollutants by magnetic Cu0/Fe3O4 submicron
           composites
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Gang Nie, Jia Huang, Yezhou Hu, Yaobin Ding, Xiaoyan Han, Heqing Tang
      Magnetic Cu0/Fe3O4 submicron composites were prepared using a hydrothermal method and used as heterogeneous catalysts for the activation of peroxymonosulfate (PMS) and the degradation of organic pollutants. The as-prepared magnetic Cu0/Fe3O4 submicron composites were composed of Cu0 and Fe3O4 crystals and had an average size of approximately 220 nm. The Cu0/Fe3O4 composites could efficiently catalyze the activation of PMS to generate singlet oxygen, and thus induced the rapid degradation of rhodamine B, methylene blue, orange II, phenol and 4-chlorophenol. The use of 0.1 g/L of the Cu0/Fe3O4 composites induced the complete removal of rhodamine B (20 μmol/L) in 15 min, methylene blue (20 μmol/L) in 5 min, orange II (20 μmol/L) in 10 min, phenol (0.1 mmol/L) in 30 min and 4-chlorophenol (0.1 mmol/L) in 15 min with an initial pH value of 7.0 and a PMS concentration of 0.5 mmol/L. The total organic carbon (TOC) removal higher than 85% for all of these five pollutants was obtained in 30 min when the PMS concentration was 2.5 mmol/L. The rate of degradation was considerably higher than that obtained with Cu0 or Fe3O4 particles alone. The enhanced catalytic activity of the Cu0/Fe3O4 composites in the activation of PMS was attributed to the synergistic effect of the Cu0 and Fe3O4 crystals in the composites. Singlet oxygen was identified as the primary reactive oxygen species responsible for pollutant degradation by electron spin resonance and radical quenching experiments. A possible mechanism for the activation of PMS by Cu0/Fe3O4 composites is proposed as electron transfer from the organic pollutants to PMS induces the activation of PMS to generate 1O2, which induces the degradation of the organic pollutants. As a magnetic catalyst, the Cu0/Fe3O4 composites were easily recovered by magnetic separation, and exhibited excellent stability over five successive degradation cycles. The present study provides a facile and green heterogeneous catalysis method for the oxidative removal of organic pollutants.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Enhanced visible light photocatalytic H2 production over Z-scheme g-C3N4
           nansheets/WO3 nanorods nanocomposites loaded with Ni(OH)x cocatalysts
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Kelin He, Jun Xie, Xingyi Luo, Jiuqing Wen, Song Ma, Xin Li, Yueping Fang, Xiangchao Zhang
      Novel WO3/g-C3N4/Ni(OH) x hybrids have been successfully synthesized by a two-step strategy of high temperature calcination and in situ photodeposition. Their photocatalytic performance was investigated using TEOA as a hole scavenger under visible light irradiation. The loading of WO3 and Ni(OH) x cocatalysts boosted the photocatalytic H2 evolution efficiency of g-C3N4. WO3/g-C3N4/Ni(OH) x with 20 wt%defective WO3 and 4.8 wt%Ni(OH) x showed the highest hydrogen production rate of 576 μmol/(g–h), which was 5.7, 10.8 and 230 times higher than those of g-C3N4/4.8 wt%Ni(OH) x , 20 wt%WO3/C3N4 and g-C3N4 photocatalysts, respectively. The remarkably enhanced H2 evolution performance was ascribed to the combination effects of the Z-scheme heterojunction (WO3/g-C3N4) and loaded cocatalysts (Ni(OH) x ), which effectively inhibited the recombination of the photoexcited electron-hole pairs of g-C3N4 and improved both H2 evolution and TEOA oxidation kinetics. The electron spin resonance spectra of •O2 − and •OH radicals provided evidence for the Z-scheme charge separation mechanism. The loading of easily available Ni(OH) x cocatalysts on the Z-scheme WO3/g-C3N4 nanocomposites provided insights into constructing a robust multiple-heterojunction material for photocatalytic applications.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Highly efficient Z-scheme WO3–x quantum dots/TiO2 for photocatalytic
           hydrogen generation
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Lun Pan, Jingwen Zhang, Xu Jia, Yu-Hang Ma, Xiangwen Zhang, Li Wang, Ji-Jun Zou
      Z-scheme semiconductors are a promising class of photocatalysts for hydrogen generation. In this work, Z-scheme semiconductors composed of WO3–x quantum dots supported on TiO2 (WO3–x QDs/TiO2) were fabricated by solvothermal and hydrogen-reduction methods. Characterization by transmission electron microscopy and X-ray diffraction indicated that the amount and size of the WO3–x QDs could be tuned by modulating the addition of the W precursor. Evidence from X-ray photoelectron spectroscopy and photoluminescence spectroscopy suggested that the hydrogen reduction of the composite induced the formation of oxygen vacancy (W5+/VO) defects in WO3. These defects led to ohmic contact between WO3-x and TiO2, which altered the charge-transfer pathway from type II heterojunction to Z-scheme, and maintained the highly reductive and oxidative ability of TiO2 and WO3–x , respectively. Therefore, the Z-scheme sample showed 1.3-fold higher photoactivity than pure TiO2 in hydrogen generation. These results suggest that the formation of W5+/VO defects at the interface is highly beneficial for the fabrication of Z-scheme photocatalysts.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Surface plasmon resonance-induced visible-light photocatalytic performance
           of silver/silver molybdate composites
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Xianglong Yang, Ying Wang, Xiao Xu, Yang Qu, Xing Ding, Hao Chen
      Novel silver/silver molybdate (Ag/Ag2MoO4) composites with surface plasmon resonance (SPR)-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate (SDS) in this study. The as prepared silver/silver molybdate (Ag/Ag2MoO4) composites were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible diffuse reflectance absorption spectroscopy (DRS) in order to investigate their crystal structure, morphology and optical property as well. The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B (RhB) under visible-light irradiation. Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4 composites. It was found that preparation conditions such as pH, reaction time, and the amount of surfactant played important roles in the formation of composites with octahedral microstructures. And the composite obtained at 160 °C using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation. Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4 during the photocatalytic process, in which both holes and •OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation. A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites. It was inferred that the photoinduced “hot” electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as •OH and •O2 − because of the SPR effects. Besides, this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption, especially in the visible region, but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.
      Graphical abstract image

      PubDate: 2017-03-13T00:21:57Z
       
  • Heterojunction between anodic TiO2/g-C3N4 and cathodic WO3/W
           nano-catalysts for coupled pollutant removal in a self-biased system
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Tingting Yu, Lifen Liu, Fenglin Yang
      An anodic TiO2/g-C3N4 hetero-junction and cathodic WO3/W were used to build a self-sustained catalytic fuel cell system for oxidizing rhodamine B or triclosan and reducing NO3 −-N to N2 simultaneously. The WO3 nano-catalyst was formed in situ by heating and oxidizing a tungsten wire in air. Cyclic voltammetry and current-time curves were used to characterize the electrochemical properties of the electrodes and system. Aeration and activation of molecular oxygen by self-biased TiO2/g-C3N4 led to the formation of reactive oxidizing species in the fuel cell. The mechanism of simultaneous anodic oxidation of pollutants and cathodic reduction of nitrate was proposed. The spontaneously formed circuit and tiny current were used simultaneously in treating two kinds of wastewater in the reactor chambers, even without light illumination or an external applied voltage. This new catalytic pollution control route can lower energy consumption and degrade many other kinds of pollutants.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Enhanced photochemical oxidation ability of carbon nitride by π–π
           stacking interactions with graphene
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Qiang Hao, Simeng Hao, Xiuxiu Niu, Xun Li, Daimei Chen, Hao Ding
      A one-pot method for the preparation of g-C3N4/reduced graphene oxide (rGO) composite photocatalysts with controllable band structures is presented. The photocatalysts are characterized by Fouirer transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope, and Mott-Schottky analysis. The valance band (VB) of g-C3N4 exhibits a noticeable positive shift upon hybridizing with rGO, and thus results in a strong photo-oxidation ability. The g-C3N4/rGO composites show a higher photodegradation activity for 2,4-dichlorophenol (2,4-DCP) and rhodamine B (RhB) under visible light irradiation (λ ≥ 420 nm). The g-C3N4/rGO-1 sample exhibits the highest photocatalytic activity, which is 1.49 and 1.52 times higher than that of bulk g-C3N4 for 2,4-DCP and 1.52 times degradation, respectively. The enhanced photocatalytic activity for g-C3N4 originates from the improved visible light usage, enhanced electronic conductivity and photo-oxidation ability by the formed strong π–π stacking interactions with rGO.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Preparation and application of g-C3N4-ZnS-DNA nanocomposite with enhanced
           electrocatalytic activity
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Xin Zhou, Jing Zou, Sheng Zhang, Ming Pan, Wanyun Gong
      We successfully designed and prepared a g-C3N4-ZnS-DNA nanocomposite by a simple method and systematically investigated its morphology, microstructure, and electrocatalytic properties. The as-prepared g-C3N4-ZnS-DNA nanocomposite possessed the electrocatalytic activity of g-C3N4-ZnS and the conductivity of DNA. The presence of DNA was found to enhance the electrocatalytic response of the nanocomposite towards environmental hormones, e.g. pentachlorophenol and nonylphenol, owing to the interaction between g-C3N4-ZnS and DNA, indicating that a stable nanocomposite was formed. The three components showed synergistic effects during electrocatalysis. Electrochemical impedance spectra indicated that the g-C3N4-ZnS-DNA nanocomposite dramatically facilitated the electron transfer of a modified electrode. The co-doping of g-C3N4 film with ZnS and DNA doubled the electrochemical response of the modified electrode in comparison with that of unmodified g-C3N4 film. The detection limits (3 S/N) of pentachlorophenol and nonylphenol were 3.3 × 10−9 mol L−1. Meanwhile, we propose a possible Z-scheme mechanism for electron transfer in the g-C3N4-ZnS-DNA nanocomposite and the possible pentachlorophenol and nonylphenol electrocatalytic oxidation mechanism. The g-C3N4-ZnS-DNA nanocomposite-modified electrode was demonstrated to be effective for electrochemical sensing of trace environmental hormones in water samples.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Facile synthesis and enhanced photocatalytic H2-evolution performance of
           NiS2-modified g-C3N4 photocatalysts
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Feng Chen, Hui Yang, Xuefei Wang, Huogen Yu
      NiS2 is a promising cocatalyst to improve the photocatalytic performance of g-C3N4 for the production of H2. However, the synthesis of the NiS2 cocatalyst usually requires harsh conditions, which risks destroying the microstructures of the g-C3N4 photocatalysts. In this study, a facile and low-temperature (80 °C) impregnation method was developed to prepare NiS2/g-C3N4 photocatalysts. First, the g-C3N4 powders were processed by the hydrothermal method in order to introduce oxygen-containing functional groups (such as –OH and –CONH–) to the surface of g-C3N4. Then, the Ni2+ ions could be adsorbed near the g-C3N4 via strong electrostatic interaction between g-C3N4 and Ni2+ ions upon the addition of Ni(NO3)2 solution. Finally, NiS2 nanoparticles were formed on the surface of g-C3N4 upon the addition of TAA. It was found that the NiS2 nanoparticles were solidly and homogeneously grafted on the surface of g-C3N4, resulting in greatly improved photocatalytic H2 production. When the amount of NiS2 was 3 wt%, the resultant NiS2/g-C3N4 photocatalyst showed the highest H2 evolution rate (116.343 μmol h−1 g−1), which is significantly higher than that of the pure g-C3N4 (3 μmol h−1 g−1). Moreover, the results of a recycling test for the NiS2/g-C3N4(3 wt%) sample showed that this sample could maintain a stable and effective photocatalytic H2-evolution performance under visible-light irradiation. Based on the above results, a possible mechanism of the improved photocatalytic performance was proposed for the presented NiS2/g-C3N4 photocatalysts, in which the photogenerated electrons of g-C3N4 can be rapidly transferred to the NiS2 nanoparticles via the close and continuous contact between them; then, the photogenerated electrons rapidly react with H2O adsorbed on the surface of NiS2, which has a surficial metallic character and high catalytic activity, to produce H2. Considering the mild and facile synthesis method, the presented low-cost and highly efficient NiS2-modified g-C3N4 photocatalysts would have great potential for practical use in photocatalytic H2 production.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Enhanced ethanol electro-oxidation on CeO2-modified Pt/Ni catalysts in
           alkaline solution
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Zhihua Xu, Lixia Rao, Haiyan Song, Zhaoxiong Yan, Lijun Zhang, Shuibin Yang
      Pt/Ni catalysts modified with CeO2 nanoparticles were prepared by simple composite electrodeposition of Ni and CeO2, and spontaneous Ni partial replacement by Pt processes. The as-prepared CeO2-modified Pt/Ni catalysts showed enhanced catalytic performance for ethanol electro-oxidation compared with pure Pt/Ni, and acetate species were proposed to be the main products of the oxidation when using these catalysts. The content of CeO2 in the as-prepared catalysts influenced their catalytic activity, with Pt/NiCe2 (obtained from an electrolyte containing 100 mg/L CeO2 nanoparticles) exhibiting higher activity and relatively better stability in ethanol electro-oxidation. This was mainly due to the oxygen storage capacity of CeO2, the interaction between Pt and CeO2/Ni, and the relatively small contact and charge transfer resistances. The results of this work thus suggest that electrocatalysts with low price and high activity can be rationally designed and produced by a simple route for use in direct ethanol fuel cells.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Three-dimensional MoS2/reduced graphene oxide aerogel as a macroscopic
           visible-light photocatalyst
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Ruiyang Zhang, Wenchao Wan, Dawei Li, Fan Dong, Ying Zhou
      Photocatalysis is regarded as an ideal technology for solving the urgent environmental and energy issues that we face today. Among the reported photocatalysts, molybdenum disulfide (MoS2) is very promising for applications in hydrogen production and pollutant photodegradation. However, its lack of active sites and the difficulty of recovering catalysts in powder form have hindered its wide application. Here, we report the successful preparation of a macroscopic visible-light responsive MoS2/reduced graphene oxide (MoS2/RGO) aerogel. The obtained MoS2/RGO aerogel exhibits enhanced photocatalytic activity towards hydrogen production and photoreduction of Cr(VI) in comparison with the MoS2 powder. In addition, the low density (56.1 mg/cm3) of the MoS2/RGO aerogel enables it to be used as an efficient adsorption material for organic pollutants. Our results demonstrate that this very promising multifunctional aerogel has potential applications in environmental remediation and clean energy production.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Enhanced visible-light photo-oxidation of nitric oxide using
           bismuth-coupled graphitic carbon nitride composite heterostructures
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Yuhan Li, Kangle Lv, Wingkei Ho, Zaiwang Zhao, Yu Huang
      Pure bismuth (Bi) metal-modified graphitic carbon nitride (g-C3N4) composites (Bi-CN) with a pomegranate-like structure were prepared by an in situ method. The Bi-CN composites were used as photocatalysts for the oxidation of nitric oxide (NO) under visible-light irradiation. The inclusion of pure Bi metal in the g-C3N4 layers markedly improved the light absorption of the Bi-CN composites from the ultraviolet to the near-infrared region because of the typical surface plasmon resonance of Bi metal. The separation and transfer of photogenerated charge carriers were greatly accelerated by the presence of built-in Mott–Schottky effects at the interface between Bi metal and g-C3N4. As a result, the Bi-CN composite photocatalysts exhibited considerably enhanced efficiency in the photocatalytic removal of NO compared with that of Bi metal or g-C3N4 alone. The pomegranate-like structure of the Bi-CN composites and an explanation for their improved photocatalytic activity were proposed. This work not only provides a design for highly efficient g-C3N4-based photocatalysts through modification with Bi metal, but also offers new insights into the mechanistic understanding of g-C3N4-based photocatalysis.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Effect of carrier and axial ligand on the photocatalytic activity of
           cobalt thioporphyrazine
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Yi Liu, Xuanmu Zhou, Zhehui Zhang, Bingguang Zhang, Kejian Deng
      The photocatalytic activity of cobalt octakis(butylthio) porphyrazine (CoPz(BuS)8) was assessed through photodegradation of the dye rhodamine B (RhB) in water under irradiation with a Xe lamp and aerated conditions. The photocatalytic activity of CoPz(BuS)8 loaded on Al2O3 or SiO2@Fe3O4 nanoparticles or coordinated with an axial azide ligand was also investigated. The results demonstrated that the photocatalytic activity of CoPz(BuS)8 loaded on Al2O3 was higher than that loaded on SiO2@Fe3O4. The kinetic curves of RhB degradation in aqueous solutions at different pH indicated the pseudo first-order kinetics of the reaction. The highest degradation rate for CoPz(BuS)8 loaded Al2O3 at pH = 4 after 160 min was 84.6%. However, the advantages of easier separation and recycling as well as the ability to terminate the reaction at any time for the CoPz(BuS)8 loaded SiO2@Fe3O4 cannot be ignored. When electron-rich NaN3 was coordinated with CoPz(BuS)8 as an axial ligand and loaded on Al2O3, the resulting catalyst produced more active oxygen species such as O2 − and HO• to promote the quicker degradation of RhB than that by the other catalysts. For the N3-coordinated CoPz(BuS)8 loaded on Al2O3, the reactions at pH = 4 and 7 distinctly deviated from first-order kinetics, and the degradation rate reached 77.6% after 80 min at pH = 4.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Construction of Ag3PO4/Ag2MoO4 Z-scheme heterogeneous photocatalyst for
           the remediation of organic pollutants
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Hua Tang, Yanhui Fu, Shufang Chang, Siyu Xie, Guogang Tang
      Hole/electron separation and charge transfer are the key processes for enhancing the visible-light photocatalysis performance of heterogeneous photocatalytic systems. To better utilize and understand these effects, binary Ag3PO4/Ag2MoO4 hybrid materials were fabricated by a facile solution-phase reaction and characterized systematically by X-ray diffraction (XRD), energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, field-emission scanning electron microscopy and ultraviolet-visible diffuse-reflectance spectroscopy. Under visible-light illumination, a heterogeneous Ag3PO4/Ag/Ag2MoO4 photocatalyst was constructed and demonstrated enhanced photocatalytic activity and photostability compared with pristine Ag3PO4 toward the remediation of the organic dye rhodamine B. The Ag3PO4/Ag2MoO4 hybrid catalyst with 8% mole fraction of Ag2MoO4 exhibited the highest photocatalytic activity toward the removal of typical dye molecules, including methyl orange, methylene blue and phenol aqueous solution. Moreover, the mechanism of the photocatalytic enhancement was investigated via hole- and radical-trapping experiments, photocurrent measurements, electrochemical impedance spectroscopy and XRD measurements. The XRD analysis revealed that metallic Ag nanoparticles formed initially on the surface of the Ag3PO4/Ag2MoO4 composites under visible-light illumination, leading to the generation of a Ag3PO4/Ag/Ag2MoO4 Z-scheme tandem photocatalytic system. The enhanced photocatalytic activity and stability were attributed to the formation of the Ag3PO4/Ag/Ag2MoO4 Z-scheme heterojunction and surface plasmon resonance of photo-reduced Ag nanoparticles on the surface. Finally, a plasmonic Z-scheme photocatalytic mechanism was proposed. This work may provide new insights into the design and preparation of advanced visible-light photocatalytic materials and facilitate their practical application in environmental issues.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Salt-assisted Synthesis of Hollow Bi2WO6 Microspheres with Superior
           Photocatalytic Activity for NO Removal
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Meijuan Chen, Yu Huang, Shun Cheng Lee
      Hollow Bi2WO6 microspheres are successfully synthesized by a facile ultrasonic spray pyrolysis (USP) method using NaCl as a salt template. The as-prepared hollow microspheres assembled as nanoplates with dimensions of approximately 41–148 nm and are dispersed with non-uniform pores on the template surface. By swapping the salt template with KCl or Na2SO4, different morphologies of Bi2WO6 are obtained. The experimental results demonstrate that NaCl plays a key role on the formation of Bi2WO6 with hollow structures. The specific growth mechanism of hollow microspheres was studied in detail. The Bi2WO6 hollow microspheres exhibit an excellent photocatalytic efficiency for NO removal under solar light irradiation, which is 1.73 times higher than for the Bi2WO6 obtained in the absence of any salt template. This enhancement can be ascribed to the simultaneous improvement on the surface area and visible light-harvesting ability from the hollow structures. Electron spin resonance (ESR) results suggest that both radicals of •OH and •O2 − are involved in the photocatalytic process over the BWO-NaCl sample. The production of •O2 − radicals offers better durability for NO removal.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Enhanced photocatalytic performance of cementitious material with TiO2@Ag
           modified fly ash micro-aggregates
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Lu Yang, Yining Gao, Fazhou Wang, Peng Liu, Shuguang Hu
      A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead (ZFAB) to improve its dispersability and exposure degree in a cement system. The application of Ag particles in TiO2/ZFAB modified cementitious materials is to further enhance the photocatalytic performance. Various Ag@TiO2/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated. It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency. With an increment of the amounts of Ag particles in the TiO2/ZFAB modified cementitious samples, the photocatalytic activities increased first and then decreased. The optimal Ag@TiO2/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene (9.91 × 10−3 min−1), which is approximately 3 and 10 times higher than those of TiO2/ZFAB and TiO2 modified samples, respectively. This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system. Thus, ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Electrodeposition of Cu2O/g-C3N4 heterojunction film on an FTO substrate
           for enhancing visible light photoelectrochemical water splitting
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Shengsen Zhang, Jie Yan, Siyuan Yang, Yuehua Xu, Xin Cai, Xin Li, Xiangchao Zhang, Feng Peng, Yueping Fang
      An immobilized Cu2O/g-C3N4 heterojunction film was successfully made on an FTO substrate by electrophoretic deposition of g-C3N4 on a Cu2O thin film. The photoelectrochemical (PEC) performance for water splitting by the Cu2O/g-C3N4 film was better than pure g-C3N4 and pure Cu2O film. Under –0.4 V external bias and visible light irradiation, the photocurrent density and PEC hydrogen evolution efficiency of the optimized Cu2O/g-C3N4 film was –1.38 mA/cm2 and 0.48 mL h−1 cm−2, respectively. The enhanced PEC performance of Cu2O/g-C3N4 was attributed to the synergistic effect of light coupling and a matching energy band structure between g-C3N4 and Cu2O as well as the external bias.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Solvent-assisted synthesis of porous g-C3N4 with efficient visible-light
           photocatalytic performance for NO removal
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Wendong Zhang, Zaiwang Zhao, Fan Dong, Yuxin Zhang
      Graphitic carbon nitride (g-C3N4) with efficient photocatalytic activity was synthesized through thermal polymerization of thiourea with the addition of water (CN-W) or ethanol (CN-E) at 550 °C for 2 h. The physicochemical properties of the g-C3N4 were investigated by X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, diffuse-reflection spectroscopy, BET and BJH surface area characterization, and elemental analysis. The carbon content was found to have self-doped into the g-C3N4 matrix during the thermal polymerization of thiourea and ethanol. CN-W and CN-E showed considerably enhanced visible-light photocatalytic activity, with NO removal percentages of 37.2% and 48.3%, respectively. Compared with pure g-C3N4, both the short and long lifetimes of the charge carriers in CN-W and CN-E were found to be prolonged. The mechanism of improved visible-light photocatalytic activity was deduced. The present work may provide a facile route to optimize the microstructure of g-C3N4 photocatalysts for high-performance environmental and energy applications.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Synthesis of C–Cl-codoped titania/attapulgite composites with enhanced
           visible-light photocatalytic activity
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Lijuan Deng, Yi Xie, Gaoke Zhang
      We demonstrate the synthesis of C–Cl-codoped titania/attapulgite (TiO2/ATT) composites containing a mixture of TiO2 phases by a facile sol-gel method at 70 °C using titanium tetraisopropoxide as the TiO2 precursor and ATT as a support for the TiO2 nanoparticles. The photocatalytic activity of the C–Cl-codoped TiO2/ATT composites with mixed anatase/brookite/rutile phases obtained at pH = 3.0 was much higher than that of commercially available Degussa P25 for the photocatalytic degradation of acid red G under visible-light irradiation. The excellent photocatalytic activity of the developed composite originates from the nonmetal codoping, which extends the absorption edge of TiO2 into visible region, and the presence of multiple phases, which slow the recombination of photoexcited electron/hole pairs. The formation of hydroxyl radicals during the photocatalytic degradation process was detected by photoluminescence probing using terephthalic acid. A mechanism for photocatalysis over the C–Cl-codoped TiO2/ATT composites was proposed.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Selective oxidative dehydrogenation of ethane to ethylene over a
           hydroxylated boron nitride catalyst
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Lei Shi, Bing Yan, Dan Shao, Fan Jiang, Dongqi Wang, An-Hui Lu
      Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene, offering rather high selectivity (95%) but only small amount of CO2 formation (0.4%) at a given ethane conversion of 11%. Even at high conversion level of 63%, the selectivity of ethylene retained at 80%, which is competitive with the energy-demanding industrialized steam cracking route. A long-term test for 200 h resulted in stable conversion and product selectivity, showing the excellent catalytic stability. Both experimental and computational studies have identified that the hydrogen abstraction of B-OH groups by molecular oxygen dynamically generated the active sites and triggered ethane dehydrogenation.
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      PubDate: 2017-03-13T00:21:57Z
       
  • High activity of a Pt decorated Ni/C nanocatalyst for hydrogen oxidation
    • Abstract: Publication date: February 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 2
      Author(s): Xiaolin Gao, Yufei Wang, Heping Xie, Tao Liu, Wei Chu
      The Pt decorated Ni/C nanocatalysts were prepared for hydrogen oxidation reaction (HOR) in fuel cell. By regulating the contents of Pt and Ni in the catalyst, both the composition and the structure affected the electrochemical catalytic characteristics of the Pt-Ni/C catalysts. When the Pt mass content was 3.1% percent and that of Ni was 13.9% percent, the Pt-Ni/C-3 catalyst exhibited a larger electrochemically active surface area and a higher exchange current density toward HOR than those of pure supported platinum sample. Our study demonstrates a feasible approach for designing the more efficient catalysts with lower content of noble metal for HOR in fuel cell.
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      PubDate: 2017-03-13T00:21:57Z
       
  • Co2C nanoprisms for syngas conversion to lower olefins with high
           selectivity
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Yunjie Ding
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      PubDate: 2017-01-28T12:55:30Z
       
  • Latest progress in hydrogen production from solar water splitting via
           photocatalysis, photoelectrochemical, and
           photovoltaic-photoelectrochemical solutions
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Rengui Li
      Hydrogen production via solar water splitting is regarded as one of the most promising ways to utilize solar energy and has attracted more and more attention. Great progress has been made on photocatalytic water splitting for hydrogen production in the past few years. This review summarizes the very recent progress (mainly in the last 2–3 years) on three major types of solar hydrogen production systems: particulate photocatalysis (PC) systems, photoelectrochemical (PEC) systems, and photovoltaic-photoelectrochemical (PV-PEC) hybrid systems. The solar-to-hydrogen (STH) conversion efficiency of PC systems has recently exceeded 1.0% using a SrTiO3:La,Rh/Au/BiVO4:Mo photocatalyst, 2.5% for PEC water splitting on a tantalum nitride photoanode, and reached 22.4% for PV-PEC water splitting using a multi-junction GaInP/GaAs/Ge cell and Ni electrode hybrid system. The advantages and disadvantages of these systems for hydrogen production via solar water splitting, especially for their potential demonstration and application in the future, are briefly described and discussed. Finally, the challenges and opportunities for solar water splitting solutions are also forecasted.
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      PubDate: 2017-01-28T12:55:30Z
       
  • Construction of an operando dual-beam fourier transform infrared
           spectrometer and its application in the observation of isobutene reactions
           over nano-sized HZSM-5 zeolite
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Jiaxu Liu, Jilei Wang, Wei Zhou, Cuilan Miao, Guang Xiong, Qin Xin, Hongchen Guo
      An operando dual-beam Fourier transform infrared (DB-FTIR) spectrometer was successfully developed using a facile method. The DB-FTIR spectrometer is suitable for the real-time study of the dynamic surface processes involved in gas/solid heterogeneous catalysis under real reaction conditions because it can simultaneously collect reference and sample spectra. The influence of gas-phase molecular vibration and heat irradiation at real reaction temperatures can therefore be eliminated. The DB-FTIR spectrometer was successfully used to follow the transformation of isobutene over nano-sized HZSM-5 zeolite under real reaction conditions.
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      PubDate: 2017-01-28T12:55:30Z
       
  • Efficient removal of ammonia with a novel graphene-supported BiFeO3 as a
           reusable photocatalyst under visible light
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Cong-yang Zou, Shou-qing Liu, Zhemin Shen, Yuan Zhang, Ni-shan Jiang, Wen-chao Ji
      Graphene-supported BiFeO3 (rG-BiFeO3) was synthesized by the hydrothermal method and used for the efficient removal of ammonia under visible light. X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy were conducted to characterize the rG-BiFeO3. The specific surface area of the rG-BiFeO3 catalyst was 48.6 m2/g, larger than that of BiFeO3 (21.0 m2/g). When used as a heterogeneous photocatalyst, rG-BiFeO3 achieved 91.20% degradation of a NH3-N solution (50 mg/L) at pH = 11 under visible-light irradiation in the absence of hydrogen peroxide. The degradation of ammonia followed pseudo-first-order kinetics, and the catalyst retained high photocatalytic activity after seven reaction cycles. Study of the mechanism showed that the holes, superoxide anion radicals, and hydroxyl radicals, arising from the synergy between graphene and BiFeO3, oxidized NH3 directly to N2.
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      PubDate: 2017-01-28T12:55:30Z
       
  • Fabrication of highly dispersed platinum-deposited porous g-C3N4 by a
           simple in situ photoreduction strategy and their excellent visible light
           photocatalytic activity toward aqueous 4-fluorophenol degradation
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Zhenxing Zeng, Kexin Li, Kai Wei, Yuhua Dai, Liushui Yan, Huiqin Guo, Xubiao Luo
      A series of highly dispersed platinum-deposited porous g-C3N4 (Pt/pg-C3N4) were successfully fabricated by a simple in situ photoreduction strategy using chloroplatinic acid and porous g-C3N4 as precursors. Porous g-C3N4 was fabricated by a pretreatment strategy using melamine as a raw material. The morphology, porosity, phase, chemical structure, and optical and electronic properties of as-prepared Pt/pg-C3N4 were characterized. The photocatalytic activity of as-prepared Pt/pg-C3N4 was preliminarily evaluated by the degradation of aqueous azo dyes methyl orange under visible light irradiation. The as-prepared Pt/pg-C3N4 were further applied to the degradation and mineralization of aqueous 4-fluorophenol. The recyclability of Pt/pg-C3N4 was evaluated under four consecutive photocatalytic runs.
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      PubDate: 2017-01-28T12:55:30Z
       
  • La-doped Pt/TiO2 as an efficient catalyst for room temperature oxidation
           of low concentration HCHO
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Honggen Peng, Jiawei Ying, Jingyan Zhang, Xianhua Zhang, Cheng Peng, Cheng Rao, Wenming Liu, Ning Zhang, Xiang Wang
      Catalytic oxidation of formaldehyde (HCHO) is the most efficient way to purify indoor air of HCHO pollutant. This work investigated rare earth La-doped Pt/TiO2 for low concentration HCHO oxidation at room temperature. La-doped Pt/TiO2 had a dramatically promoted catalytic performance for HCHO oxidation. The reasons for the La promotion effect were investigated by N2 adsorption, X-ray diffraction, CO chemisorption, X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and high-angle annular dark field scanning TEM. The Pt nanoparticle size was reduced to 1.7 nm from 2.2 nm after modification by La, which led to higher Pt dispersion, more exposed active sites and enhanced metal-support interaction. Thus a superior activity for indoor low concentration HCHO oxidation was obtained. Moreover, the La-doped TiO2 can be wash-coated on a cordierite monolith so that very low amounts of Pt (0.01 wt%) can be used. The catalyst was evaluated in a simulated indoor HCHO elimination environment and displayed high purifying efficiency and stability. It can be potentially used as a commercial catalyst for indoor HCHO elimination.
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      PubDate: 2017-01-28T12:55:30Z
       
  • One-step post-synthesis treatment for preparing hydrothermally stable
           hierarchically porous ZSM-5
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Jian Ding, Teng Xue, Haihong Wu, Mingyuan He
      Hierarchically porous ZSM-5 (SiO2/Al2O3 ≈ 120) containing phosphorus was prepared by a one-step post-synthesis treatment involving controlled desilication and phosphorous modification. The hierarchically porous ZSM-5 featured high thermal and hydrothermal stability. The obtained ZSM-5 zeolites were systematically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption, NH3 temperature-programmed desorption, and 27Al and 31P magic-angle spinning nuclear magnetic resonance spectroscopy. The prepared ZSM-5 displayed enhanced activity and prolonged lifetime toward hydrocarbon cracking. The high activity was attributed to improved coke tolerance owing to the presence of the highly stable mesoporous network of ZSM-5 and acid sites introduced upon phosphorus modification. Additionally a mechanism of the stabilization of the zeolites by phosphorus was proposed and discussed.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • One-pot conversion of cyclohexanol to ɛ-caprolactam using a
           multifunctional Na2WO4-acidic ionic liquid catalytic system
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Hefang Wang, Liyuan Jia, Rongbin Hu, Meidan Gao, Yanji Wang
      Na2WO4-acidic ionic liquid was used as a simple, ecofriendly, recyclable and efficient catalytic system for the one-pot conversion of cyclohexanol to ɛ-caprolactam. The effect of the structure of the ionic liquid on the catalytic activity of this system was investigated, and the results revealed that sulfonic acid-functionalized ionic liquids with HSO4 − as an anion gave the best results. The highly efficient performance of this catalyst system was attributed to the phase-transfer behavior of the cation of the ionic liquid, the improved coordination of the substrate to bisperoxotungstate during the oxidation reaction, and the stabilization of the intermediate formed during the Beckmann rearrangement.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Gas-phase epoxidation of propylene by molecular oxygen over Ag-Cu-Cl/BaCO3
           catalyst: Effects of Cu and Cl loadings
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Qing Zhang, Yanglong Guo, Wangcheng Zhan, Yun Guo, Li Wang, Yunsong Wang, Guanzhong Lu
      Ag-Cu-Cl/BaCO3 catalysts with different Cl and Cu loadings, prepared by the reduction deposition impregnation method, were investigated for gas-phase epoxidation of propylene by molecular oxygen and characterized by X-ray diffraction, X-ray photoelectron spectroscopy and O2 temperature programmed desorption. Ag-Cu-Cl/BaCO3 catalyst with 0.036 wt% Cu and 0.060 wt% Cl exhibited the highest catalytic performance for gas-phase epoxidation of propylene by molecular oxygen. A propylene oxide selectivity of 83.7% and propylene conversion of 1.2% were achieved under the reaction conditions of 20% C3H6-10% O2-70% N2, 200 °C, 0.1 MPa and 3000 h−1. Increasing the Cl loading allowed Ag to ensemble easier, whereas changing the Cu loading showed little effect on Ag crystallite size. The appropriate Cl loading of Ag-Cu-Cl/BaCO3 catalyst can reduce the dissociation adsorption of oxygen to atomic oxygen species leading to the combustion of propylene to CO2, which benefits epoxidation of propylene by molecular oxygen. Excessive Cl loading of Ag-Cu-Cl/BaCO3 catalyst decreases propylene conversion and propylene oxide selectivity remarkably because of Cl poisoning. The appropriate Cu loading of Ag-Cu-Cl/BaCO3 catalyst is efficient for the epoxidation of propylene by molecular oxygen, and an excess Cu loading decreases propylene oxide selectivity because the aggregation of Cu species increases the exposed surfaces of Ag nanoparticles, which was shown by slight increases in atomic oxygen species adsorbed. The appropriate loadings of Cu and Cl of Ag-Cu-Cl/BaCO3 catalyst are important to strike the balance between molecular oxygen and atomic oxygen species to create a favorable epoxidation of propylene by molecular oxygen.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Fabrication and catalytic behavior of hierarchically-structured nylon 6
           nanofiber membrane decorated with silver nanoparticles
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Huihui Zhao, Weimin Kang, Xiaomin Ma, Nanping Deng, Zongjie Li, Bowen Cheng
      A hierarchically-structured nylon 6 (PA6) nanofiber membrane decorated with silver nanoparticles (Ag NPs) was fabricated by electrospinning and impregnation methods. The as-fabricated hierarchically-structured Ag/PA6 nanofiber membrane (HS-Ag/PA6 NM) exhibits a morphology in which Ag NPs are deposited on the surfaces of both thick fibers and thin fibers. The content and size of the Ag NPs can be controlled by varying the concentration of the silver colloid solution. Compared with the non-hierarchically-structured Ag/PA6 nanofiber membrane, HS-Ag/PA6 NM has a higher specific surface area and exhibits a higher degradation rate for methylene blue of 81.8%–98.1% within 2 h. HS-Ag/PA6 NM can be easily recycled and exhibits good reusability. It retains a degradation rate for methylene blue of 83.5% after five consecutive cycles. The hierarchically-structured nanofiber membrane is therefore a potential nanocatalyst.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Ag-loaded mesoporous Pb3Nb2O8 photocatalysts with enhanced activity under
           visible-light irradiation
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Xiaopeng Han, Jianan Lü, Li Tian, Lingru Kong, Xuemei Lu, Yong Mei, Jiwei Wang, Xiaoxing Fan
      Mesoporous Pb3Nb2O8 photocatalysts were synthesized by the evaporation-induced self-assembly (EISA) method. Ag was deposited on the surface of mesoporous Pb3Nb2O8 by a facile photoreduction process. The as-prepared samples were characterized by TG-DSC, XRD, N2 adsorption, HR-TEM and UV-Vis spectroscopy. The results revealed that mesoporous Pb3Nb2O8 has a large specific surface area and uniform pore size distribution both before and after Ag deposition. The photodegradation of 2-propanol and acetaldehyde gas under visible-light (λ > 420 nm) irradiation was employed to evaluate the photocatalytic activities of the samples. The results showed that the photocatalytic activity of mesoporous Pb3Nb2O8 is greatly improved by the Ag co-catalyst. These mesoporous Pb3Nb2O8 exhibit photocatalytic activities as much as 41 times higher when compared with the Pb3Nb2O8 prepared by the solid state reaction method. The content of loaded Ag ranged from 0.5% to 5% (Ag2SO4). The optimal loading was determined to be 1% corresponding the highest photocatalytic activity. These results clearly indicate that the activity of Pb3Nb2O8 can be improved to obtain an outstanding performance for the photodegradation of organic pollutants.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Catalytic performance enhancement by alloying Pd with Pt on ordered
           mesoporous manganese oxide for methane combustion
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Peng Xu, Zhixing Wu, Jiguang Deng, Yuxi Liu, Shaohua Xie, Guangsheng Guo, Hongxing Dai
      Ordered mesoporous Mn2O3 (meso-Mn2O3) and meso-Mn2O3-supported Pd, Pt, and Pd-Pt alloy x(Pd y Pt)/meso-Mn2O3; x = (0.10−1.50) wt%; Pd/Pt molar ratio (y) = 4.9−5.1 nanocatalysts were prepared using KIT-6-templated and poly(vinyl alcohol)-protected reduction methods, respectively. The meso-Mn2O3 had a high surface area, i.e., 106 m2/g, and a cubic crystal structure. Noble-metal nanoparticles (NPs) of size 2.1−2.8 nm were uniformly dispersed on the meso-Mn2O3 surfaces. Alloying Pd with Pt enhanced the catalytic activity in methane combustion; 1.41(Pd5.1Pt)/meso-Mn2O3 gave the best performance; T 10%, T 50%, and T 90% (the temperatures required for achieving methane conversions of 10%, 50%, and 90%) were 265, 345, and 425 °C, respectively, at a space velocity of 20000 mL/(g·h). The effects of SO2, CO2, H2O, and NO on methane combustion over 1.41(Pd5.1Pt)/meso-Mn2O3 were also examined. We conclude that the good catalytic performance of 1.41(Pd5.1Pt)/meso-Mn2O3 is associated with its high-quality porous structure, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interactions between Pd-Pt alloy NPs and the meso-Mn2O3 support.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Thermodynamic study of direct amination of isobutylene to tert-butylamine
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Shangyao Gao, Xiangxue Zhu, Xiujie Li, Yuzhong Wang, Ye Zhang, Sujuan Xie, Jie An, Fucun Chen, Shenglin Liu, Longya Xu
      On basis of thermodynamic empirical equations, the thermodynamic parameters for the direct amination of isobutylene to tert-butylamine, an atomically economic and green chemical reaction, were calculated. In particular, the equilibrium conversion of isobutylene under various reaction conditions close to those used in industry was calculated and discussed. Isobutylene amination is a temperature sensitive reaction due to its exothermic nature and isobutylene equilibrium conversion decreases with temperature. However, kinetically, the amination reaction will be faster at a higher temperature. Thus, there must be an optimum temperature for the reaction. A high pressure and n(NH3)/n(i-C4H8) molar ratio promote the transformation of isobutylene to tert-butylamine. Developing a highly efficient catalyst under mild reaction conditions is preferred for the amination process. The reaction was investigated over a series of acidic zeolites. ZSM-11 zeolite exhibited the best performance with 14.2% isobutylene conversion (52.2% of the equilibrium conversion) and > 99.0% tert-butylamine selectivity. The effect of reaction conditions on the performance of the ZSM-11 catalyst agreed with the thermodynamic results, which provides guidance for further catalyst development and reaction condition optimization.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Cu(I)-catalyzed cascade reaction of N-tosylhydrazones with 3-butyn-1-ol: A
           new synthesis of tetrahydrofurans
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Mohammad Lokman Hossain, Kang Wang, Fei Ye, Yan Zhang, Jianbo Wang
      The Cu(I)-catalyzed cascade coupling/cyclization reaction of N-tosylhydrazones with 3-butyn-1-ol has been explored. This new strategy represents a simple platform for the synthesis of tetrahydrofurans in moderate to good yields.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Enhanced MTO performance over acid treated hierarchical SAPO-34
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Shu Ren, Guojuan Liu, Xian Wu, Xinqing Chen, Minghong Wu, Gaofeng Zeng, Ziyu Liu, Yuhan Sun
      Hierarchical SAPO-34 crystals were synthesized by a facile acid etching post-treatment. Butterfly-shaped porous patterns on four side faces and hierarchical pores composed of micropores, mesopores and macropores were formed after a nitric acid or oxalic acid treatment. The catalytic performance of the hierarchical SAPO-34 for the methanol to olefins (MTO) process showed that the synergistic effect of the hierarchical pores and acid sites resulted in a longer catalyst lifetime (from 210 to 390 min for the acid treated SAPO-34) and higher selectivity to light olefins of 92%–94%. The ethylene selectivity can be adjusted between 37.4% and 51.5% by the pore size. No hierarchical SAPO-34 was obtained after a treatment with butanedioic acid, and with this sample, fast deactivation was detected after 100 min.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Preparation of graphene/MgCl2-supported Ti-based Ziegler-Natta catalysts
           by the coagglomeration method and their application in ethylene
           polymerization
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Hexin Zhang, Jae-Hyeong Park, Young-Kwon Moon, Eun-Bin Ko, Dong-ho Lee, Yanming Hu, Xuequan Zhang, Keun-Byoung Yoon
      We report a facile coagglomeration method for preparing graphene (G)/MgCl2-supported Ti-based Ziegler-Natta catalysts. The effects of graphene feed ratio on catalyst morphology and ethylene polymerization behavior were examined. The synthesized catalyst exhibited very high activity for ethylene polymerization. The resultant polyethylene (PE)/G nanocomposites showed a layered morphology, and the graphene fillers were well dispersed in the PE matrix. In addition, the thermal stability and mechanical properties of PE were significantly enhanced with the introduction of a very small amount of G fillers (0.05 wt%). This work provides a facile approach to the production of high-performance PE.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Enhancing hydrothermal stability of nano-sized HZSM-5 zeolite by
           phosphorus modification for olefin catalytic cracking of full-range FCC
           gasoline
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Yun Zhao, Jiaxu Liu, Guang Xiong, Hongchen Guo
      In this study, phosphorus modification by trimethyl phosphate impregnation was employed to enhance the hydrothermal stability of nano-sized HZSM-5 zeolites. A parallel modification was studied by ammonium dihydrogen phosphate impregnation. The modified zeolites were subjected to steam treatment at 800 °C for 4 h (100% steam) and employed as catalysts for olefin catalytic cracking (OCC) of full-range fluid catalytic cracking (FCC) gasoline. X-ray diffraction, N2 physical adsorption and NH3 temperature-programmed desorption analysis indicated that, although significant improvements to the hydrothermal stability of nano-sized HZSM-5 zeolites can be observed when adopting both phosphorus modification strategies, impregnation with trimethyl phosphate displays further enhancement of the hydrothermal stability. This is because higher structural crystallinity is retained, larger specific surface areas/micropore volumes form, and there are greater numbers of surface acid sites. Reaction experiments conducted using a fixed-bed micro-reactor (catalyst/oil ratio = 4, time on stream = 4 s) showed OCC of full-range FCC gasoline—under a fluidized-bed reaction mode configuration—to be a viable solution for the olefin problem of FCC gasoline. This reaction significantly decreased the olefin content in the full-range FCC gasoline feed, and specifically heavy-end olefins, by converting the olefins into value-added C2–C4 olefins and aromatics. At the same time, sulfide content of the gasoline decreased via a non-hydrodesulfurization process. Nano-sized HZSM-5 zeolites modified with trimethyl phosphate exhibited enhanced catalytic performance for OCC of full-range FCC gasoline.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Influence of preparation methods on the physicochemical properties and
           catalytic performance of MnOx-CeO2 catalysts for NH3-SCR at low
           temperature
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Xiaojiang Yao, Kaili Ma, Weixin Zou, Shenggui He, Jibin An, Fumo Yang, Lin Dong
      This work examines the influence of preparation methods on the physicochemical properties and catalytic performance of MnO x -CeO2 catalysts for selective catalytic reduction of NO by NH3 (NH3-SCR) at low temperature. Five different methods, namely, mechanical mixing, impregnation, hydrothermal treatment, co-precipitation, and a sol-gel technique, were used to synthesize MnO x -CeO2 catalysts. The catalysts were characterized in detail, and an NH3-SCR model reaction was chosen to evaluate the catalytic performance. The results showed that the preparation methods affected the catalytic performance in the order: hydrothermal treatment > sol-gel > co-precipitation > impregnation > mechanical mixing. This order correlated with the surface Ce3+ and Mn4+ content, oxygen vacancies and surface adsorbed oxygen species concentration, and the amount of acidic sites and acidic strength. This trend is related to redox interactions between MnO x and CeO2. The catalyst formed by a hydrothermal treatment exhibited excellent physicochemical properties, optimal catalytic performance, and good H2O resistance in NH3-SCR reaction. This was attributed to incorporation of Mn n+ into the CeO2 lattice to form a uniform ceria-based solid solution (containing Mn-O-Ce structures). Strengthening of the electronic interactions between MnO x and CeO2, driven by the high-temperature and high-pressure conditions during the hydrothermal treatment also improved the catalyst characteristics. Thus, the hydrothermal treatment method is an efficient and environment-friendly route to synthesizing low-temperature denitrification (deNO x ) catalysts.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Influence of sulfation on CeO2-ZrO2 catalysts for NO reduction with NH3
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): He Zhang, Yonggang Zou, Yue Peng
      CeO2-ZrO2 (CeZr) and sulfated CeO2-ZrO2 (S-CeZr) catalysts were prepared for the selective catalytic reduction of NO with NH3. The CeZr catalysts exhibited higher activity at low temperatures (< 200 °C) and lower activity at high temperatures (> 200 °C) than the S-CeZr catalysts. The sulfation of CeZr was studied in terms of surface acidity, redox properties and NO adsorption-desorption by temperature-dependent experiments and in situ infrared spectroscopy. S-CeZr displayed high concentrations of acidic sites and increased surface acidities, but poor reducibility compared with CeZr. The high acidity of S-CeZr was attributed to the presence of Brønsted acid sites, arising mainly from the surface sulfates. Because the surface was covered with sulfate species, S-CeZr showed lower NO adsorption and weaker oxidation ability than CeZr. The adsorption of NH3 on the Brønsted acid sites restricted the reaction with NO at low temperatures, but the selective catalytic reduction cycle occurred easily at relatively low temperatures (150 °C), and the weakly bound nitrite was partially activated on the S-CeZr catalyst at relatively high temperatures (300 °C). The catalytic mechanisms for the CeZr and S-CeZr catalysts at 150 and 300 °C were also studied.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • A shaped binderless ZSM-11 zeolite catalyst for direct amination of
           isobutene to tert-butylamine
    • Abstract: Publication date: January 2017
      Source:Chinese Journal of Catalysis, Volume 38, Issue 1
      Author(s): Wanshuo Zhang, Shangyao Gao, Sujuan Xie, Hui Liu, Xiangxue Zhu, Yongchen Shang, Shenglin Liu, Longya Xu, Ye Zhang
      A shaped binderless and two binder-containing ZSM-11 zeolite catalysts were prepared and characterized by powder X-ray diffraction, N2 adsorption-desorption, and pyridine adsorption-infrared measurements. The binderless catalyst was synthesized using a dry-gel conversion technique, in which 1,6-hexanediamine and tetrabutylammonium bromide were used as structure-directing agents and no other alkaline materials were added. The catalytic performance of the zeolites in the direct amination of isobutene to tert-butylamine was evaluated in a fixed-bed reactor. By virtue of its high crystallinity as well as its good mechanical strength, the shaped binderless ZSM-11 catalyst showed a higher rate of formation of tert-butylamine than did the binder-containing catalysts.
      Graphical abstract image

      PubDate: 2017-01-28T12:55:30Z
       
  • Adsorption/reaction energetics measured by microcalorimetry and correlated
           with reactivity on supported catalysts: A review
    • Abstract: Publication date: December 2016
      Source:Chinese Journal of Catalysis, Volume 37, Issue 12
      Author(s): Lin Li, Jian Lin, Xiaoyu Li, Aiqin Wang, Xiaodong Wang, Tao Zhang
      The formations and transformations of the chemical bonds of reactants and intermediates on catalyst surfaces occur in conjunction with the evolution of heat during catalytic reactions. Measurement of this evolved heat is helpful in terms of understanding the nature of the interactions between the catalyst and the adsorbed species, and provides insights into the reactivity of the catalyst. Although various techniques have previously been applied to assessments of evolved heat, direct measurements using a Tian-Calvet microcalorimeter are currently the most reliable method for this purpose. In this review, we summarize the relationship between the adsorption/reaction energetics determined by microcalorimetry and the reactivities of supported catalysts, and examine the important role of microcalorimetry in understanding catalytic performance from the energetic point of view.© 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.
      Graphical abstract image

      PubDate: 2017-01-06T06:45:17Z
       
  • Selective reduction of carbon dioxide to carbon monoxide over Au/CeO2
           catalyst and identification of reaction intermediate
    • Abstract: Publication date: December 2016
      Source:Chinese Journal of Catalysis, Volume 37, Issue 12
      Author(s): Xiaobing Zhu, Xin Qu, Xiaosong Li, Jinglin Liu, Jianhao Liu, Bin Zhu, Chuan Shi
      CO2 selective reduction to CO with H2 over a CeO2-supported nano-Au catalyst at atmospheric pressure was investigated. A high CO2 conversion, approaching the thermodynamic equilibrium value, and nearly 100% CO selectivity were obtained. The surface formate intermediates generated during the reverse water-gas shift reaction at 400 °C were identified using in situ diffuse-reflectance infrared Fourier-transform spectroscopy. The formate consumption to give CO and H2O, determined using mass spectrometry, indicated that the reaction proceeded via an associative formate mechanism; this contributes to the high Au/CeO2 catalytic activity at low temperatures.
      Graphical abstract image

      PubDate: 2017-01-06T06:45:17Z
       
  • Time-resolved photoluminescence of anatase/rutile TiO2 phase junction
           revealing charge separation dynamics
    • Abstract: Publication date: December 2016
      Source:Chinese Journal of Catalysis, Volume 37, Issue 12
      Author(s): Xiuli Wang, Shuai Shen, Zhaochi Feng, Can Li
      Junctions are an important structure that allows charge separation in solar cells and photocatalysts. Here, we studied the charge transfer at an anatase/rutile TiO2 phase junction using time-resolved photoluminescence spectroscopy. Visible (∼500 nm) and near-infrared (NIR, ∼830 nm) emissions were monitored to give insight into the photoinduced charges of anatase and rutile in the junction, respectively. New fast photoluminescence decay components appeared in the visible emission of rutile-phase dominated TiO2 and in the NIR emission of many mixed phase TiO2 samples. The fast decays confirmed that the charge separation occurred at the phase junction. The visible emission intensity from the mixed phase TiO2 increased, revealing that charge transfer from rutile to anatase was the main pathway. The charge separation slowed the microsecond time scale photoluminescence decay rate for charge carriers in both anatase and rutile. However, the millisecond decay of the charge carriers in anatase TiO2 was accelerated, while there was almost no change in the charge carrier dynamics of rutile TiO2. Thus, charge separation at the anatase/rutile phase junction caused an increase in the charge carrier concentration on a microsecond time scale, because of slower electron-hole recombination. The enhanced photocatalytic activity previously observed at anatase/rutile phase junctions is likely caused by the improved charge carrier dynamics we report here. These findings may contribute to the development of improved photocatalytic materials.
      Graphical abstract image

      PubDate: 2017-01-06T06:45:17Z
       
  • Fe-Beta zeolite for selective catalytic reduction of NOx with NH3:
           Influence of Fe content
    • Abstract: Publication date: December 2016
      Source:Chinese Journal of Catalysis, Volume 37, Issue 12
      Author(s): Yan Xia, Wangcheng Zhan, Yun Guo, Yanglong Guo, Guanzhong Lu
      Fe doped Beta zeolite with different Fe contents were prepared by ion exchange by changing the volume or the concentration of a Fe salt solution. For a particular mass of Fe salt precursor, the concentration of the metal salt solution during ion exchange influenced the ion exchange capacity of Fe, and resulted in different activities of the Fe-Beta catalyst. Fe-Beta catalysts with the Fe contents of (2.6, 6.3 and 9) wt% were synthesized using different amounts of 0.02 mol/L Fe salt solution. These catalysts were studied by various characterization techniques and their NH3-SCR activities were evaluated. The Fe-Beta catalyst with the Fe content of 6.3 wt% exhibited the highest activity, with a temperature range of 202–616 °C where the NO x conversion was > 80%. The Fe content in Beta zeolite did not influence the structure of Beta zeolite and valence state of Fe. Compared with the Fe-Beta catalysts with low Fe content (2.6 wt%), Fe-Beta catalysts with 6.3 wt% Fe content possessed more isolated Fe3+ active sites which led to its higher NH3-SCR activity. A high capacity for NH3 and NO adsorption, and a high activity for NO oxidation also contributed to the high NH3-SCR activity of the Fe-Beta catalyst with 6.3 wt%. However, when the Fe content was further increased to 9.0 wt%, the amount of Fe x O y nanoparticles increased while the amount of isolated Fe3+ active sites was unchanged, which promoted NH3 oxidation and decreased the NH3-SCR activity at high temperature.
      Graphical abstract image

      PubDate: 2017-01-06T06:45:17Z
       
  • Electro-polymerization fabrication of PANI@GF electrode and its
           energy-effective electrocatalytic performance in electro-Fenton process
    • Abstract: Publication date: December 2016
      Source:Chinese Journal of Catalysis, Volume 37, Issue 12
      Author(s): Jinli Yu, Tianfu Liu, Haiyue Liu, Yi Wang
      An energy-effective polyaniline coated graphite felt (PANI@GF) composite cathode for the electro-Fenton (E-Fenton) process was synthesized through an electro-polymerization method. The electrocatalytic activity of the cathode for the 2e− ORR process was investigated and dimethyl phthalate (DMP) was used as a model substrate to evaluate its performance in the E-Fenton process. The as-prepared PANI@GF composite possessed a three-dimensional porous structure, which is favorable for O2 diffusion, while the large amount of N atoms in the conductive polyaniline (PANI) enhanced 2e− ORR reactivity. The DMP degradation of the E-Fenton system using PANI@GF was significantly enhanced owing to the improvement in ORR performance. The apparent kinetic constant for DMP degradation was 0.0753 min−1, five times larger than that of GF. The optimal carbonization temperature and polymerization time for the preparation of the PANI@GF composite cathode was found to be 900 °C and 1 h, respectively. Measurement conditions are a crucial factor for proper evaluation of cathode electrocatalytic performance. Accordingly, the O2 flow rate, Fe2+ concentration, and pH for DMP degradation were optimized at 0.4 L/min, 1.0 mmol/L, and 3.0, respectively. These results indicate that the present PANI@GF composite cathode is energy-effective and promising for potential use as an E-Fenton system cathode for the removal of organic pollutants in wastewater.
      Graphical abstract image

      PubDate: 2017-01-06T06:45:17Z
       
 
 
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