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  Subjects -> ENGINEERING (Total: 2269 journals)
    - CHEMICAL ENGINEERING (190 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)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 7)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
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)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
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 Applied Catalysis A: General
  [SJR: 1.234]   [H-I: 159]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0926-860X
   Published by Elsevier Homepage  [3041 journals]
  • SO42−/TiO2 promotion on HZSM-5 for catalytic cracking of paraffin
    • Authors: Xu Hou; Yuan Qiu; Enxian Yuan; Xiangwen Zhang; Guozhu Liu
      Pages: 12 - 23
      Abstract: Publication date: 5 May 2017
      Source:Applied Catalysis A: General, Volume 537
      Author(s): Xu Hou, Yuan Qiu, Enxian Yuan, Xiangwen Zhang, Guozhu Liu
      A new kind of SO4 2−/TiO2/ZSM-5 catalysts were prepared by the sequential TiO2-CLD and sulfation of commercial HZSM-5 zeolite. Characterization results revealed that the external surface of ZSM-5 crystallite was wrapped by SO4 2−/TiO2 phase; at the same time, the unique MFI-structure and pore properties were well preserved, and the new L acid sites were generated on the external surface. The surface SO4 2−/TiO2 phase promoted the paraffin saturation adsorption by 8%, and significantly enhanced the diffusion process in the ZSM-5 based catalysts. Compared to the parent HZSM-5 zeolite, a significant promotion of catalytic activity in n-pentane cracking was observed over the SO4 2−/TiO2/ZSM-5 catalysts, which was probably due to the enhancement of sorption process for the gas-phase n-pentane molecules into HZSM-5 crystallite caused by the surface SO4 2−/TiO2 phase. Moreover, the SO4 2−/TiO2/ZSM-5 catalysts with a suitable TiO2-loading exhibited excellent catalytic stability and coke-resistance ability in normal-paraffin cracking. A possible role of the surface SO4 2−/TiO2 phase in coke formation was proposed that it effectively hindered the routes from olefins to aromatic hydrocarbons, and thus restrained the accumulation of coke deposit on the external surface.
      Graphical abstract image

      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.03.002
      Issue No: Vol. 537 (2017)
       
  • Surfactant-directed mesoporous zeolites with enhanced catalytic activity
           in tetrahydropyranylation of alcohols: Effect of framework type and
           morphology
    • Authors: Hye Sun Shin; Maksym Opanasenko; Carlos Palomino Cabello; Ryong Ryoo; Jiří Čejka
      Pages: 24 - 32
      Abstract: Publication date: 5 May 2017
      Source:Applied Catalysis A: General, Volume 537
      Author(s): Hye Sun Shin, Maksym Opanasenko, Carlos Palomino Cabello, Ryong Ryoo, Jiří Čejka
      Nanosponge zeolite beta was hydrothermally synthesized using multi-quarternary ammonium surfactant as a meso-micro hierarchical structure directing agent. The nanosponge morphology of the beta zeolite consisted of randomly interconnected nanocrystals with thickness of 10–20nm. The beta nanosponges with highly mesoporous structure exhibited enhanced catalytic activity in tetrahydropyranylation of alcohols (methanol, 1-octanol, cyclohexanol and 2-adamantanol) when compared with the conventional beta zeolites and nanosponge zeolites of MTW and MFI framework types. The enhanced catalytic performance (∼60% conversion with 90–100% selectivity towards tetrahydropyranyl ether and over two times higher initial rate compared to other zeolites) of hierarchical beta nanosponges can be attributed to the high accessibility of acid sites and facile diffusion of reactants and products through the mesopores.
      Graphical abstract image

      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.02.019
      Issue No: Vol. 537 (2017)
       
  • Porous silicon carbide as a support for Mn/Na/W/SiC catalyst in the
           oxidative coupling of methane
    • Authors: Huan Wang; Roman Schmack; Benjamin Paul; Matthias Albrecht; Sergey Sokolov; Stefan Rümmler; Evgenii V. Kondratenko; Ralph Kraehnert
      Pages: 33 - 39
      Abstract: Publication date: 5 May 2017
      Source:Applied Catalysis A: General, Volume 537
      Author(s): Huan Wang, Roman Schmack, Benjamin Paul, Matthias Albrecht, Sergey Sokolov, Stefan Rümmler, Evgenii V. Kondratenko, Ralph Kraehnert
      Efficient conversion of methane to higher hydrocarbons via oxidative coupling of methane “OCM” is one of the dream reactions in heterogeneous catalysis. Promising yields of C2 hydrocarbons were reported for nanostructured catalysts based on Mn/Na/W-SiO2. However, the exact role of the nanostructure could not be studied so far due to collapse of the pore structure of the SiO2 support at typical OCM temperatures. We investigate porous SiC as an alternative catalyst support for OCM catalysis. Mn/Na/W/SiC catalysts with different pore size were synthesized via impregnation, calcined under different atmospheres and then studied in OCM. The calcination critically impacts the pore structure and surface area of the obtained catalysts. Calcination in nitrogen preserves the support’s structure significantly better than calcination in air. However, the nitrogen-calcined catalysts show a strong loss of porosity during OCM testing. The loss of porosity is caused by the presence of Na, which induces a melting of the surface layer that typically protects SiC against bulk oxidation. OCM tests suggest that the activity and C2 yield of Mn/Na/W/SiC catalysts depend critically on the supports stability, i.e. the surface area retained under reaction conditions.
      Graphical abstract image

      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.02.018
      Issue No: Vol. 537 (2017)
       
  • Improving the ceria-mediated water and carbon dioxide splitting through
           the addition of chromium
    • Authors: Sotiria Mostrou; Robert Büchel; Sotiris E. Pratsinis; Jeroen A. van Bokhoven
      Pages: 40 - 49
      Abstract: Publication date: 5 May 2017
      Source:Applied Catalysis A: General, Volume 537
      Author(s): Sotiria Mostrou, Robert Büchel, Sotiris E. Pratsinis, Jeroen A. van Bokhoven
      The solar thermochemical water and carbon dioxide splitting, mediated by ceria, has a great potential to produce “green” syngas. Chromium was added to ceria to improve the syngas production. Three preparation methods were applied, resulting in different morphologies allowing to investigate the role of chromium. The samples were characterized by X‐ray diffraction, Raman and X-ray spectroscopy, and electron microscopy. Materials made by polymerized-complex-method and dry-impregnation consisted of two crystal phases: ceria and chromia. In contrast, materials made by flame-spray pyrolysis exhibited a homogeneous Cr-doped ceria phase, and chromia was found only at a chromium-content higher than 25mol%. The chromium-doped ceria released additional oxygen during the formation of CeCrO3 perovskite, which did not enhance hydrogen or carbon monoxide production. All chromia-containing samples exhibited improved oxygen exchange capacity, possibly due to a redox cycle of chromia itself, and significantly improved the activity of water and carbon dioxide splitting. Hydrogen production increased from 3.2 to 6.7mL/g and the time to reach redox equilibrium was shorten from 41 to 3min. The best hydrogen and carbon dioxide production rates were up to 20 and 500 times higher than pure ceria, respectively. The presence of chromium is therefore crucial as a catalyst, promoter, and oxygen storage enhancer. This work emphasises the importance of a catalysed re‐oxidation reaction and demonstrates that a metal oxide, becoming active in situ, can catalyse water and carbon dioxide splitting.
      Graphical abstract image

      PubDate: 2017-03-16T02:37:15Z
      DOI: 10.1016/j.apcata.2017.03.001
      Issue No: Vol. 537 (2017)
       
  • Platinum nanoparticles onto pegylated poly(lactic acid) stereocomplex for
           highly selective hydrogenation of aromatic nitrocompounds to anilines
    • Authors: Werner Oberhauser; Claudio Evangelisti; Cristina Tiozzo; Mattia Bartoli; Marco Frediani; Elisa Passaglia; Luca Rosi
      Pages: 50 - 58
      Abstract: Publication date: 5 May 2017
      Source:Applied Catalysis A: General, Volume 537
      Author(s): Werner Oberhauser, Claudio Evangelisti, Cristina Tiozzo, Mattia Bartoli, Marco Frediani, Elisa Passaglia, Luca Rosi
      A stereocomplexed poly(lactic acid)-polyethyleneglycol copolymer was synthesized and successfully used as recyclable support for Pt nanoparticles, generated by the metal vapor synthesis technique. The confinement of the Pt nanoparticles were determined by thermal analysis. Hydrogenation reactions of chlorinated aromatic nitro compounds, containing other reducible functional groups, to the corresponding anilines occurred with the latter supported Pt nanoparticles in MeOH under very mild reaction conditions (i.e. 30°C, p(H2)=5.0bar). The covalently attached polyethyleneglycol polymer significantly increased the catalytic activity of the supported Pt nanoparticles compared to an analogous catalytic system which did not contain polyethyleneglycol but the same sized Pt nanoparticles.
      Graphical abstract image

      PubDate: 2017-03-16T02:37:15Z
      DOI: 10.1016/j.apcata.2017.03.003
      Issue No: Vol. 537 (2017)
       
  • Application of Brazilian dolomites and mixed oxides as catalysts in tar
           removal system
    • Authors: Cristina P.B. Quitete; Mariana M.V.M. Souza
      Pages: 1 - 8
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Cristina P.B. Quitete, Mariana M.V.M. Souza
      Two different classes of catalysts, three dolomites with different origins and two Ni- based mixed oxides containing cerium or lanthanum, were used on tar removal by steam reforming. Mixed oxides presented higher toluene conversion than dolomites, which lost activity due to hydration and carbonation. Mixed oxides were quite active for toluene steam reforming, obtaining high conversions for long periods, 16h at 700°C and 70h at 800°C. Despite the good activity, the samples showed high coke content after reaction, probably caused by the low steam/carbon ratio. The coked catalyst can be completely regenerated by steam. Thermodynamic simulation of coking tendency showed that carbon is formed at low temperatures even at high steam/carbon ratios.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.014
      Issue No: Vol. 536 (2017)
       
  • Effect of the preparation conditions on the catalytic activity of calcined
           Ca/Al-layered double hydroxides for the synthesis of glycerol carbonate
    • Authors: Judith Granados-Reyes; Pilar Salagre; Yolanda Cesteros
      Pages: 9 - 17
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Judith Granados-Reyes, Pilar Salagre, Yolanda Cesteros
      The effect of the preparation conditions of several calcined Ca/Al layered double hydroxide compounds (CaAl-LDH) on the catalytic transesterification of glycerol with dimethyl carbonate to obtain glycerol carbonate has been studied. The CaAl-LDH precursors were prepared by aging under microwaves or conventional heating, and using chlorides or nitrates as interlayer anions. Calcination conditions, such as temperature, time and calcination system, were modified. After 3h of reaction, the catalysts obtained by calcination at 450°C for 15h in air exhibited moderate-high glycerol conversion (46–76%) and moderate selectivity to glycerol carbonate (41–65%). Calcination at 450°C at longer calcination time or the use of a dynamic inert-atmosphere system during calcination led to higher conversion (89–94%) and higher selectivity to glycerol carbonate (72–73%). This has been related to the higher basicity of these catalysts. Finally, calcination at 750°C resulted in high conversion (88–98%) and high selectivity to glycerol carbonate (60–85%) due to the presence in the catalysts of highly basic CaO. Several catalytic reuses favoured the decarboxylation of glycerol carbonate resulting in the formation of higher amounts of glycidol (42%). The progressive loss of conversion and selectivity to glycerol carbonate observed has been attributed to the loss of some CaO basic centres during reaction.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.013
      Issue No: Vol. 536 (2017)
       
  • NiO diluted in high surface area TiO2 as an efficient catalyst for the
           oxidative dehydrogenation of ethane
    • Authors: R. Sanchis; D. Delgado; S. Agouram; M.D. Soriano; M.I. Vázquez; E. Rodríguez-Castellón; B. Solsona; J.M.López Nieto
      Pages: 18 - 26
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): R. Sanchis, D. Delgado, S. Agouram, M.D. Soriano, M.I. Vázquez, E. Rodríguez-Castellón, B. Solsona, J.M.López Nieto
      Catalysts consisting of NiO diluted in high surface area TiO2 can be as efficient in the oxidative dehydrogenation of ethane as the most selective NiO-promoted catalysts reported previously in the literature. By selecting the titania matrix and the NiO loading, yields to ethylene over 40% have been obtained. In the present article, three different titanium oxides (TiO2) have been employed as supports or diluters of nickel oxide and have been tested in the oxidative dehydrogenation of ethane to ethylene. All TiO2 used present anatase as the main crystalline phase and different surface areas of 11, 55 and 85m2 g−1. It has been observed that by selecting an appropriate nickel loading and the titanium oxide extremely high selectivity towards ethylene can be obtained. Thus, nickel oxide supported on TiO2 with high surface areas (i.e. 55 and 85m2 g−1) have resulted to give the best catalytic performance although the optimal nickel loading is different for each case. The optimal catalyst has been obtained for NiO-loadings up to 5–10 theoretical monolayers regardless of the TiO2 employed. Free TiO2 is inactive whereas unsupported NiO is active and unselective (forming mainly carbon dioxide) and, therefore, unmodified NiO particles have to be avoided in order to obtain the optimal catalytic performance. The use of low surface area titania (11m2 g−1) have led to the lowest selectivity to olefin due to the presence of an excess of free NiO particles.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.012
      Issue No: Vol. 536 (2017)
       
  • Aerobic oxidation of benzyl alcohol in water catalyzed by gold
           nanoparticles supported on imidazole containing crosslinked polymer
    • Authors: Huan Wang; Yuanyuan Shi; Masatake Haruta; Jiahui Huang
      Pages: 27 - 34
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Huan Wang, Yuanyuan Shi, Masatake Haruta, Jiahui Huang
      A series of imidazole containing crosslinked copolymer poly(divinylbenzene-co-N- vinylimidazole) (PDVB-VI-n) supported Au catalysts were prepared by using AuCl3 as the precursor. The resulting Au/PDVB-VI-n catalysts were employed to catalyze the aerobic oxidation of benzyl alcohol with molecular oxygen as the sole oxidant and water as the solvent. By optimizing the sizes of Au NPs and the composition of PDVB-VI-n, Au/PDVB-VI-n exhibited the excellent activities even only using a small amount of basic K2CO3. Interestingly, the conversion of benzyl alcohol increased monotonously with the increase of Au sizes in the range of 2–5nm, but the selectivity to benzoic acid increased first and then decreased gradually. The highest selectivity to benzoic acid of ∼80%was achieved over ∼3.2nm Au NPs.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.015
      Issue No: Vol. 536 (2017)
       
  • Facile preparation of a silver nanoparticles-containing membrane with an
           enhanced catalysis and separation
    • Authors: Shengkui Ma; Xi Chen; Bowu Zhao; Hualin Dong; Qianxuan Yuan; Liying Li; Juan Lv; Linqi Shi; Li Chen
      Pages: 35 - 44
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Shengkui Ma, Xi Chen, Bowu Zhao, Hualin Dong, Qianxuan Yuan, Liying Li, Juan Lv, Linqi Shi, Li Chen
      A composite membrane was facilely fabricated by the simultaneous in situ reducing silver ions and anchoring of the formed silver nanoparticles (NPs) inside a poly (dopamine) (PDA)-modified poly (vinlidene fluoride) (PVDF) membrane which was prepared by the PVDF powders modified via dopamine. The composite membrane showed a typical unsymmetrical structure with membrane surface and pore having Ag NPs. The PDA of the membrane effectively prevented the Ag NPs’ agglomeration and leaching, beneficial to the Ag NPs’ catalysis and stability. When a cross-flow model was applied to circulate p-nitrophenol through the composite membrane, a rapid catalytic reduction could be obtained. Ag NPs of the membrane surface have the main contribution to the catalysis compared with the ones of membrane pores. However, Ag NPs of membrane pores could efficiently catalyze the reduction of the reactants flowing through the membrane pores more thoroughly. By the synergy of Ag NPs on membrane surface and in membrane pores, highly purified products could be directly separated from the system during reaction process. In the whole process, additional steps for separating Ag NPs and products were omitted, significantly decreasing the operating cost. In addition, the Ag NPs of the composite membrane obtained high reactive activity. All the advantages make the composite membrane have attractive prospects for catalytic reaction and separation.

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.009
      Issue No: Vol. 536 (2017)
       
  • Green diesel production over nickel-alumina co-precipitated catalysts
    • Authors: Mantha Gousi; Chrysanthi Andriopoulou; Kyriakos Bourikas; Spyros Ladas; Malamas Sotiriou; Christos Kordulis; Alexis Lycourghiotis
      Pages: 45 - 56
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Mantha Gousi, Chrysanthi Andriopoulou, Kyriakos Bourikas, Spyros Ladas, Malamas Sotiriou, Christos Kordulis, Alexis Lycourghiotis
      A series of nickel-alumina co-precipitated catalysts with varying nickel loading in the range (0–100wt% nickel) was prepared under close control of the preparation parameters. The catalysts were characterized using nitrogen adsorption-desorption isotherms, NH3-TPD, XRD, XPS, SEM and HRTEM. They were tested for the selective deoxygenation (SDO) of sunflower oil into hydrocarbons in the diesel range under solvent-free conditions at 310°C and hydrogen pressure of 40bar for various reaction times up to 9h using a semi-batch reactor and a “volume of oil (ml)/mass of catalyst (g)” ratio equal to 100. The products were analyzed using GS and GC–MS. The preparative procedure resulted to high specific surface area mesoporous materials with nanocrystals of nickel phases in close contact with alumina nanograins, thus providing high nickel surface area. Normal-alkanes in the diesel range were produced whereas intermediate stearic acid and esters of fatty acids have been also detected. Considerable amounts of high molecular weight esters (intermediate products) are formed during SDO under solvent free conditions. Propane, ethane, methane, CO, and CO2 have been also detected in the gas phase. The conversion of sunflower oil and the total yield to hydrocarbons increases with the nickel content up to the sample containing 60wt% nickel (yield to hydrocarbons equal to 61wt%) and then it decreases. The nickel active surface correlates very well with the total yield to hydrocarbons.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.010
      Issue No: Vol. 536 (2017)
       
  • The role of different state ZnO over non-stoichiometric Zn–Cr spinel
           catalysts for isobutanol synthesis from syngas
    • Authors: Shaopeng Tian; Li Tan; Yingquan Wu; Yongli Kou; Hongjuan Xie; Noritatsu Tsubaki; Yisheng Tan
      Pages: 57 - 66
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Shaopeng Tian, Li Tan, Yingquan Wu, Yongli Kou, Hongjuan Xie, Noritatsu Tsubaki, Yisheng Tan
      A series of Zn–Cr based catalysts were prepared using combustion method (Comb-ZC), impregnation method (Impr-ZC), coprecipitation method (Copr-ZC) and fractional precipitation method (Frac-ZC). The catalysts were then examined for their ability to selectively convert syngas into higher alcohol with a special alcohol distribution (high selectivity for isobutanol). CO conversion of ca. 25%, alcohol selectivity of ca. 49% and selectivity of ca. 26% for isobutanol was achieved over the Frac-ZC catalyst. The better performance of Frac-ZC catalyst could be explained by smaller zinc oxide particle size, the higher proportion of non-stoichiometric Zn–Cr spinel phase and the good synergic effects between zinc oxide phase and non-stoichiometric Zn–Cr spinel phase. The better reducibility as well as appropriate CO-absorption property of Frac-ZC catalyst also plays an essential role in the process of isobutanol synthesis. The study also shows the excess zinc oxide could aggravate the cation disorder distribution in non-stoichiometric Zn–Cr spinel structure that provide more defects and oxygen vacancies for boosting isobutanol formation.
      Graphical abstract image

      PubDate: 2017-03-03T13:30:13Z
      DOI: 10.1016/j.apcata.2017.02.016
      Issue No: Vol. 536 (2017)
       
  • Enhanced photoelectrocatalytic performance for water oxidation by
           polyoxometalate molecular doping in BiVO4 photoanodes
    • Authors: Lu Xi; Zhanbin Jin; Zhixia Sun; Ran Liu; Lin Xu
      Pages: 67 - 74
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Lu Xi, Zhanbin Jin, Zhixia Sun, Ran Liu, Lin Xu
      Modifying bismuth vanadate (BiVO4) photoanode with secondary component is a promising strategy for improving the performance of photoelectrocatalytic water oxidation. Herein, we investigate on polyoxometalates (POMs) molecular doping in BiVO4 photoanodes to improve photoelectrocatalytic water oxidation performance of BiVO4. The water oxidation performance of BiVO4/POMs photoanodes was markedly enhanced in comparison with pristine BiVO4 photoanode. Moreover, the improved photoelectrocatalytic performance of BiVO4/POMs composite photoanodes is clearly relevant to the type and amount of POMs. The mechanism of the photogenerated electron transfer from BiVO4 to POMs is also revealed by photoluminescence spectroscopy and surface photovoltage measurements. Such a mechanism suggests that the introduction of POMs is capable of facilitating charge separation and transport as well as retarding electron-hole recombination.
      Graphical abstract image

      PubDate: 2017-03-03T13:30:13Z
      DOI: 10.1016/j.apcata.2017.02.017
      Issue No: Vol. 536 (2017)
       
  • Elucidation of phosphorus interaction in dual component zeolite/matrix
           catalysts: Selectivity control in olefin oligomerization with MTW/Al2O3
    • Authors: Christopher P. Nicholas; Laszlo T. Nemeth; William M. Plencner; Thomas M. Mezza; Collette L. Nicholas; Sesh Prabhakar; Wharton Sinkler
      Pages: 75 - 84
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Christopher P. Nicholas, Laszlo T. Nemeth, William M. Plencner, Thomas M. Mezza, Collette L. Nicholas, Sesh Prabhakar, Wharton Sinkler
      Treatment of alumina bound MTW zeolite extrudates with H3PO4 causes conversion of the binding matrix from Al2O3 to tridymite AlPO4 and we show the crystalline AlPO4 coats the surface of the MTW zeolite crystals. In this transformation, the surface area and pore volume of the catalyst decrease precipitously, but the MTW crystallinity remains largely intact. Similar, but less specific behavior was observed when using NH4H2PO4 as the phosphorus source. After phosphate treatment, the interaction of P with zeolite framework Al is a major effect reducing acidity of the zeolite. These two effects allow for selectivity control during oligomerization of propylene and butenes. Increasing the phosphorus content of the catalyst from 0 to 10wt% causes a decrease in the amount of liquid product heavier than gasoline from 15wt% to 3wt%. Concomitantly, the selectivity to triisobutylenes increases to almost 50%. Thus we attain catalytic performance similar to traditional solid phosphoric acid catalyst, but with a significant yield of triisobutylenes.
      Graphical abstract image

      PubDate: 2017-03-03T13:30:13Z
      DOI: 10.1016/j.apcata.2017.02.008
      Issue No: Vol. 536 (2017)
       
  • Reconstructed Mg-Al hydrotalcites prepared by using different rehydration
           and drying time: Physico-chemical properties and catalytic performance in
           aldol condensation
    • Authors: O. Kikhtyanin; Z. Tišler; R. Velvarská; D. Kubička
      Pages: 85 - 96
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): O. Kikhtyanin, Z. Tišler, R. Velvarská, D. Kubička
      Aldol condensation in presence of reconstructed hydrotalcites as basic catalysts is well documented and attracts an increased attention because it allows producing complex molecules starting from relatively simpler ones. Nevertheless, more studies are necessary for the better understanding of preparation factors that affect the physico-chemical properties of these materials and their catalytic performance. This work considers the effect of the duration of the liquid-phase rehydration of Mg-Al mixed oxide as well as the drying duration of prepared samples on their physico-chemical properties and performance in aldol condensation of furfural and acetone. The properties of all materials were investigated by XRD, TGA, TGA-MS, SEM and DRIFT. Experiments on aldol condensation of furfural and acetone were performed by using a stirred batch reactor at T=25°C with Ac:F=5 molar ratio. The characterization of the prepared materials showed that the recovery of HTC structure occurred within a few seconds of the contact between Mg-Al mixed oxide with liquid water. The content of functional species in all reconstituted HTCs was nearly constant and independent on preparation conditions while the amount of physisorbed water in the prepared samples decreased with increasing drying time. The calcination of as-prepared HTC followed by the subsequent rehydration of Mg-Al mixed oxide resulted in the replacement of >90% carbonate groups on hydroxyls which are Brønsted basic sites. Consequently, the activity of the reconstructed HTCs in aldol condensation of furfural and acetone was significantly higher compared to Mg-Al mixed oxide. The catalytic performance of rehydrated materials was almost independent on rehydration time while furfural conversion decreased if carrying out the reaction in an aqueous medium with increased water content. On the other hand, properly dried reconstructed HTC with the absence of physisorbed water also exhibited a very low activity in the reaction. The effect of Cannizzaro reaction as a simultaneous process with aldol condensation on the composition of reaction products was also considered. The obtained results may be useful for optimizing the preparation conditions of reconstructed HTC as a basic catalyst as well as for evaluating their performance during long-term catalytic tests.
      Graphical abstract image

      PubDate: 2017-03-21T08:28:03Z
      DOI: 10.1016/j.apcata.2017.02.020
      Issue No: Vol. 536 (2017)
       
  • Oxidative dehydrogenation of but-1-ene with lattice oxygen in ferrite
           catalysts
    • Authors: Takayasu Kiyokawa; Naoki Ikenaga
      Pages: 97 - 103
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): Takayasu Kiyokawa, Naoki Ikenaga
      The oxidative dehydrogenation (ODH) of but-1-ene was carried out using the lattice oxygen in ferrite catalysts in the temperature range of 200–300°C with a fixed-bed flow reactor at atmospheric pressure. Various ferrite catalysts, such as NiFe2O4/AC-500, ZnFe2O4/AC-500, CoFe2O4/AC-500, and CuFe2O4/AC-500, -400, -300, -280, were prepared in the presence of activated carbon in the calcination temperature range of 280–500°C. When but-1-ene-TPR was measured using various ferrite catalysts, CuFe2O4/AC-500 progressed the ODH of but-1-ene at 200–300°C. Among the catalysts, CuFe2O4/AC-500 showed the highest Buta-1,3-diene (BD) yield, at 270°C. XRD and XPS analyses of the catalyst after the ODH suggested that the lattice oxygen in Cu-O bonded to the tetrahedral site (Cu2+ T) of the ferrite structure was used for the ODH. In addition, the used catalyst was recovered by re-oxidation with molecular O2. Moreover, CuFe2O4/AC-280, which calcined at 280°C, had the highest specific surface area and improved the BD yield with an increase in contact area with but-1-ene. In the repeated ODH (reaction and regeneration cycle), CuFe2O4/AC-500 and -280 catalysts maintained BD yields of 7.5% and 11.3%, respectively. BD production is thought to be related to the amount of Cu2+ T.
      Graphical abstract image

      PubDate: 2017-03-21T08:28:03Z
      DOI: 10.1016/j.apcata.2017.02.004
      Issue No: Vol. 536 (2017)
       
  • Tailoring the physical and catalytic properties of lanthanum oxycarbonate
           nanoparticles
    • Authors: C. Estruch Bosch; M.P. Copley; T. Eralp; E. Bilbé; J.W. Thybaut; G.B. Marin; P. Collier
      Pages: 104 - 112
      Abstract: Publication date: 25 April 2017
      Source:Applied Catalysis A: General, Volume 536
      Author(s): C. Estruch Bosch, M.P. Copley, T. Eralp, E. Bilbé, J.W. Thybaut, G.B. Marin, P. Collier
      The synthesis of lanthanum oxide and its carbonate analogues has been performed by flame spray pyrolysis (FSP). Two different feeds have been studied: an organic solution and an aqueous/organic microemulsion. A key experimental parameter of FSP, the O2 dispersion, i.e., the flow rate of the dispersing gas in the FSP nozzle, exhibits an effect on the properties of the materials prepared. Increasing the level of O2 dispersion led to an increase in surface area and a decrease in mean particle size and basicity when a lanthanum containing organic solution was used as FSP feed. Lanthanum can form different phases, such as oxides, hydroxides, oxycarbonates and carbonates. The increase of O2 dispersion also produced a phase change, going from a mixture of type Ia and type II La2O2CO3 and La2O3 to pure La2O3. The use of an aqueous/organic microemulsion feed, which had a higher viscosity than the organic feed, resulted in materials with a lower surface area and a higher mean particle size than those prepared using the organic solution at the same O2 dispersion. In this case a mixture of type II La2O2CO3 and La2O3 was obtained. The materials were tested for oxidative coupling of methane (OCM). We were able to demonstrate that the OCM performance of the materials could be modified by changing the synthesis parameters. For example, lower O2 dispersion produced the highest CH4 and O2 conversions. We also demonstrated that on ageing the mean particle size remain stable; however, the phases do not, showing a new phase, La(OH)3, formation and resulting in an increase in OCM activity. While the OCM performances are modest they do demonstrate the power of this approach for controlled synthesis of lanthanum materials.
      Graphical abstract image

      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.01.019
      Issue No: Vol. 536 (2017)
       
  • A highly effective catalyst of Co-CeO2 for the oxidation of diesel soot:
           The excellent NO oxidation activity and NOx storage capacity
    • Authors: Jianan Xu; Guanzhong Lu; Yun Guo; Yanglong Guo; Xue-Qing Gong
      Pages: 1 - 8
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): Jianan Xu, Guanzhong Lu, Yun Guo, Yanglong Guo, Xue-Qing Gong
      In the catalytic combustion of diesel soot, the role of NO in the exhaust emission and the simultaneous reduction of NO by soot are two fascinating problems. Herein, the Co-CeO2 catalyst prepared by the citrate acid sol-gel method was developed to catalyze the NOx-assisted soot oxidation. The effect of the Co amount on the physicochemical and catalytic properties of the Co-CeO2 catalysts was investigated in detail. When the molar ratio of Co/Ce was 50/50, the Co50Ce50 mixed oxide catalyst exhibited the lowest soot oxidation temperature (T m of 335°C) in the feed gas of NO+O2, and the presence of water can improve obviously the catalytic combustion of soot with T m of 310°C. The presence of Co can improve the reduction of surface oxygen of ceria, and Ce can promote the reduction of Co3O4 to CoO, resulting in the enhancement of the catalytic activity of Co-CeO2 for NO oxidation and its capacity for NO2 storage as the surface nitrates. The soot oxidation on the Co-CeO2 catalyst can be promoted by “NO2-assistance”: the nitrate species are preferentially formed on the Co active sites and stored on the catalyst surface, and then NO2 produced by NO oxidation and the decomposition of nitrate stored on the surface at lower temperature, reacts with soot. That is, the stored NOx species initiates the beginning of soot oxidation, and the NO oxidation ability of the catalyst is responsible for the extensive soot oxidation by NO+O2, in which NO is reduced by carbon in soot combustion. The combination of high NO oxidation activity and high NO2 storage capacity makes the Co50Ce50 oxide catalyst as an efficient catalyst for the NOx-assisted soot oxidation.
      Graphical abstract image

      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.02.005
      Issue No: Vol. 535 (2017)
       
  • Vapor-phase catalytic dehydration of 1,4-butanediol to 3-buten-1-ol over
           modified ZrO2 catalysts
    • Authors: Hailing Duan; Tomoya Hirota; Shota Ohtsuka; Yasuhiro Yamada; Satoshi Sato
      Pages: 9 - 16
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): Hailing Duan, Tomoya Hirota, Shota Ohtsuka, Yasuhiro Yamada, Satoshi Sato
      Vapor-phase catalytic dehydration of 1,4-butanediol (1,4-BDO) was investigated over modified ZrO2 catalysts. In the dehydration of 1,4-BDO over monoclinic ZrO2 (m-ZrO2), an unsaturated alcohol, 3-buten-1-ol (3B1OL), was produced together with tetrahydrofuranand γ-butyrolactone. Among alkaline earth metal oxide modifiers, CaO with an appropriate content significantly enhanced the 3B1OL selectivity of m-ZrO2. The modification of CaO was more efficient over m-ZrO2 than tetragonal ZrO2. CO2-TPD measurements reveal that CaO supported on m-ZrO2 calcined at 800°C or higher generated new basic sites, which are attributed from Ca-O-Zr hetero-linkages, for the effective formation of 3B1OL from 1,4-BDO. In order to create more Ca-O-Zr hetero-linkages on the m-ZrO2 surface efficiently, additional ZrO2 was loaded on m-ZrO2 together with CaO via a co-impregnation method. At an appropriate weight ratio of CaO/ZrO2 =7/2 loaded on m-ZrO2, both the 1,4-BDO conversion and the 3B1OL selectivity were enhanced greatly. Especially, the 3B1OL selectivity exceeded 90% at 350°C.
      Graphical abstract image

      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.01.024
      Issue No: Vol. 535 (2017)
       
  • Catalytic reactions of coke with dioxygen and steam over
           alkaline-earth-metal-doped cerium-zirconium mixed oxides
    • Authors: Kehua Yin; Shilpa Mahamulkar; Jiahan Xie; Hirokazu Shibata; Andrzej Malek; Liwei Li; Christopher W. Jones; Pradeep Agrawal; Robert J. Davis
      Pages: 17 - 23
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): Kehua Yin, Shilpa Mahamulkar, Jiahan Xie, Hirokazu Shibata, Andrzej Malek, Liwei Li, Christopher W. Jones, Pradeep Agrawal, Robert J. Davis
      A series of cerium-zirconium mixed oxides doped with alkaline earth metals was prepared by calcining a mixture of Ce0.8Zr0.2O2 and the nitrate salt of alkaline earth metals at 1173K. The results from X-ray diffraction, Raman spectroscopy and analytical electron microscopy indicated the alkaline earth compounds were dispersed on the surface of Ce0.8Zr0.2O2. The doped mixed oxides were evaluated in the catalytic reaction of solid coke under tight contact conditions with 10 vol.% O2 in He at 693K and with 100vol.% H2O at 993K using thermogravimetric analysis. For coke oxidation with O2, the weight loss was first order in coke, and the measured first order rate constant was proportional to the total surface area of catalyst at low catalyst loadings. For coke gasification with H2O, the weight loss was nearly zero order in coke, and the measured areal reaction rate was independent of the total surface area of catalyst at low catalyst loadings. The addition of alkaline earth metals inhibited coke oxidation with dioxygen but promoted coke gasification with steam.
      Graphical abstract image

      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.02.002
      Issue No: Vol. 535 (2017)
       
  • Integrated study on the role of solvent, catalyst and reactant in the
           hydrodeoxygenation of eugenol over nickel-based catalysts
    • Authors: Jingbo Qi; Xianyong Sun; Si-Fu Tang; Yuanyuan Sun; Chen Xu; Xiaoyu Li; Xuebing Li
      Pages: 24 - 31
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): Jingbo Qi, Xianyong Sun, Si-Fu Tang, Yuanyuan Sun, Chen Xu, Xiaoyu Li, Xuebing Li
      The hydrodeoxygenation (HDO) of phenols to hydrocarbons is a very promising technique process for the lignin valorization. To reveal the role of reactant, solvent and catalyst, the HDO experiments of eugenol to hydrocarbons were carried out at 523K under 3MPa H2 over Ni catalysts supported on activated carbon (AC) and MFI-type zeolites in polar water and nonpolar n-hexane, respectively. It was found that Ni/AC was more efficient for the HDO of eugenol in water than in n-hexane, but Ni/HZSM-5 was just the opposite. The respective roles of Brønsted acid sites and Lewis acid sites on supports were also investigated by employing NaZSM-5, HZSM-5 and silicalite-1 as supports. It was revealed that Brønsted acid showed superior advantages (TOF: 37.9h−1 to 11.1h−1) over Lewis acid in the dehydration of 4-propyl-cyclohexanol. Oxygen-containing functional groups could be removed from the aromatic ring completely over Ni/HZSM-5 in n-hexane.
      Graphical abstract image

      PubDate: 2017-02-17T08:56:17Z
      DOI: 10.1016/j.apcata.2017.01.020
      Issue No: Vol. 535 (2017)
       
  • Olefin poly/oligomerizations by metal precatalysts bearing
           non–heterocyclic N–donor ligands
    • Authors: Srinivasa Budagumpi; Rangappa S. Keri; Andrea Biffis; Siddappa A. Patil
      Pages: 32 - 60
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): Srinivasa Budagumpi, Rangappa S. Keri, Andrea Biffis, Siddappa A. Patil
      The use of transition metal complexes of non–heterocyclic N–donor ligands as olefin oligo/polymerization precatalysts is reviewed. These metal complexes with definite steric and electronic variations offer high catalytic activity resulting in the desired microstructure of the polymer products currently attracting significant attention by the catalysis community. This review primarily discusses the fundamental principles in the design of mononuclear, homodinuclear, heterodinuclear, homomultinuclear and heteromultinuclear transition metal complexes having non–heterocyclic N–donor ligands and their reactivity towards olefins in oligo/polymerization reactions. Numerous non–heterocyclic N–donor ligands of the donor types N2, NO, NP, NC, N2P, N2O, N2C, N2S, N3, NCP, NCp, NOCp, N3Cp, N2O2 for mononuclear, N4, N2O2, N4O4, N3C, NCp2, N2Cp2, N2Indene2 and N2S2Indene (Cp: cyclopentadiene) for bimetallic and N8, N8O4, N8O8 and N12O4 for multinuclear complex formations have been efficiently employed, and the resulting complexes display promising reactivity patterns with a variety of olefins. The majority of these catalytic systems are tethered with appropriate alkyl/aryl/alkyl–aryl substituents to afford the required steric hindrance to the metal center(s), and with functional groups for electronic variations. Such systems produce a linear polymer product in most of the cases, any deviation from this behavior resulting in the formation of oligomers. The major focus of this review is on reports published over the last 25 years in the research and development of non–heterocyclic, N–donor coordinated transition metal complexes with a variety of spacers. This review article is organized into main sections on the basis of the nuclearity of the transition metal complex; each subsection deals with complexes starting from late transition metals on the basis of ligand type.
      Graphical abstract image

      PubDate: 2017-02-17T08:56:17Z
      DOI: 10.1016/j.apcata.2017.02.003
      Issue No: Vol. 535 (2017)
       
  • Effect of the metal precursor on the catalytic performance of the Ru/KL
           system for the ethanol transformation reactions
    • Authors: M. Almohalla; E. Gallegos-Suárez; A. Arcoya; J. Álvarez-Rodríguez; I. Rodríguez-Ramos; A. Guerrero-Ruiz
      Pages: 61 - 68
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): M. Almohalla, E. Gallegos-Suárez, A. Arcoya, J. Álvarez-Rodríguez, I. Rodríguez-Ramos, A. Guerrero-Ruiz
      Four Ru/KL-zeolite catalysts containing 2wt% of Ru were prepared from Ru3(CO)12, RuNO(NO3)3, Ru(C5H7O2)3 and RuCl3 precursors. The evolution of electronic structure and local chemical environment of ruthenium in the samples named Ru(c)/KL, Ru(n)/KL, Ru(acac)/KL and Ru(Cl)/KL was studied by in-situ XANES during temperature-programmed reduction. Also by CO chemisorption and transmission electron microscopy (TEM) the sizes of the Ru nanoparticles were determined. Activity and selectivity of the catalysts were evaluated in the transformation of ethanol, under kinetic conditions, in a fixed bed flow reactor, at 523K–573K. Characterization of the samples shows that metal dispersion values follow the trend Ru(c)/KL≥Ru(n)/KL > Ru(Cl)/KL≥Ru(acac)/KL. Activity of the catalysts is in the order Ru(acac)/KL≥Ru(c)/KL>Ru(n)/KL≥Ru(Cl)/KL. The TOF values, however, are in the same order of magnitude for all the samples, nonetheless the Ru(Cl)/KL catalyst has slightly lower TOF at all the reaction temperatures. Selectivity towards the dehydrogenation product, acetaldehyde, follows the trend Ru(c)/KL>Ru(n)/KL=Ru(acac)/KL>>Ru(Cl)/KL, this being 100% for Ru(c)/KL. Selectivity towards acetaldehyde is highly diminished for Ru(Cl)/KL in favor of the dehydration products, diethyl ether and ethylene, the higher the decrease the higher the temperature. The catalytic results are related to the properties of the surface metal species and their location in the zeolite framework, as well as to their surroundings, as evidenced from the results of the characterization measurements, which are in turn influenced by the different nature of the metal precursor.
      Graphical abstract image

      PubDate: 2017-02-17T08:56:17Z
      DOI: 10.1016/j.apcata.2017.02.007
      Issue No: Vol. 535 (2017)
       
  • Selective removal of external Ni nanoparticles on Ni@silicalite-1 single
           crystal nanoboxes: Application to size-selective arene hydrogenation
    • Authors: D. Laprune; A. Tuel; D. Farrusseng; F.C. Meunier
      Pages: 69 - 76
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): D. Laprune, A. Tuel, D. Farrusseng, F.C. Meunier
      Undesired metal nanoparticles located outside zeolite nanoboxes (hollow zeolites) can be formed during the preparation of zeolite-embedded metal nanoparticles. The present work demonstrates that it is possible to use citric acid to selectively leach out most of the external Ni nanoparticles from a Ni@silicalite-1 material. The leached sample exhibited an improved selectivity in the hydrogenation of toluene as compared to that of the bulkier mesitylene.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.011
      Issue No: Vol. 535 (2017)
       
  • Aerobic oxidation of alcohols over Ru-Mn-Ce and Ru-Co-Ce catalysts: The
           effect of calcination temperature
    • Authors: Gui Liu; Junhua Liu; Wenxiu Li; Cheng Liu; Fang Wang; Junkai He; Curtis Guild; Jing Jin; David Kriz; Steven L. Suib
      Pages: 77 - 84
      Abstract: Publication date: 10 April 2017
      Source:Applied Catalysis A: General, Volume 535
      Author(s): Gui Liu, Junhua Liu, Wenxiu Li, Cheng Liu, Fang Wang, Junkai He, Curtis Guild, Jing Jin, David Kriz, Steven L. Suib
      Two ternary mixed oxides, Ru-Mn-Ce and Ru-Co-Ce, were prepared by a co-precipitation method and used in the aerobic oxidation of alcohols to corresponding aldehydes (ketones). Interestingly, different catalytic results were obtained when these compounds were calcined. The calcination temperature had an adverse effect on the catalytic performance of Ru-Mn-Ce catalysts, while being beneficial to the Ru-Co-Ce catalysts. To illustrate these effects, these materials were characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Temperature-programmed reduction (TPR), Electron paramagnetic resonance (EPR) and other techniques. The data showed that ruthenium oxides were uniformly dispersed in the mixed oxides, and phase transformations occur after calcination. Mn3O4 was transformed to MnO2 for the Ru-Mn-Ce catalyst, while CoO(OH) was transformed to Co3O4 in the Ru-Co-Ce catalyst. The interactions between ruthenium oxides and Co (Mn)-Ce mixed oxides of the former strengthened while the latter weakened. Calcination decreased the content of adsorbed oxygen and restricted oxygen transfer mechanism in the manganese system, while the opposite effect was observed with the cobalt-containing catalyst. Under optimal reaction conditions, various kinds of alcohols were transformed to corresponding aldehydes (ketones) in high yields over the Ru-Mn-Ce catalyst suggesting these ternary oxides are environmental friendly and economical catalytic systems.
      Graphical abstract image

      PubDate: 2017-02-24T09:06:08Z
      DOI: 10.1016/j.apcata.2017.02.006
      Issue No: Vol. 535 (2017)
       
  • A long term study of the gas phase of low pressure Fischer-Tropsch
           products when reducing an iron catalyst with three different reducing
           gases
    • Authors: Joshua Gorimbo; Xiaojun Lu; Xinying Liu; Diane Hildebrandt; David Glasser
      Pages: 1 - 11
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Joshua Gorimbo, Xiaojun Lu, Xinying Liu, Diane Hildebrandt, David Glasser
      Low pressure Fischer-Tropsch synthesis was tested using iron catalysts reduced by three different reducing gases. In this regards, three reactors were set up in parallel and each of them loaded with the same quantity of the iron catalyst (FeCuKSiO2). After loading, the catalysis in the first reactor was reduced with synthesis gas (a combination of carbon monoxide and hydrogen). The catalyst in the second reactor was reduced using hydrogen (H2) gas, and while that in the third reactor was reduced with carbon monoxide (CO) gas. In this study only the gas-phase products leaving the reactors were analysed and compared under the same operating conditions such as flow rate, pressure and temperature for 1000h TOS. The results obtained indicate that the initial use of different reducing agents does not have a large impact on the long term catalyst activity but does have an impact on long term selectivity. The three reactors stabilize to about the same overall CO conversion of 14.5% which corresponds to a consumption rate of 2.64×10−4 mol/min.gcat (reactivity) after about 150h while the selectivities in the three reactors are not the same. Methane selectivity showed the trend: Carbon monoxide reduced>Syngas reduced>Hydrogen reduced. Furthermore, reducing with CO gives much more olefins than reducing with syngas and H2. The paraffin production rates did not follow a consistent trend.
      Graphical abstract image

      PubDate: 2017-01-28T14:57:21Z
      DOI: 10.1016/j.apcata.2017.01.013
      Issue No: Vol. 534 (2017)
       
  • Influence of fuel additives in the urea-nitrates solution combustion
           synthesis of Ni-Al2O3 catalyst for slurry phase CO methanation
    • Authors: Yuan Gao; Fanhui Meng; Yang Cheng; Zhong Li
      Pages: 12 - 21
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Yuan Gao, Fanhui Meng, Yang Cheng, Zhong Li
      Urea–nitrates solution combustion system was facile modified by adding various fuel additives, and used for synthesizing nanosized Ni–Al2O3 catalysts. Among the three kind of fuel additives, i.e., ammonium acetate, starch and polyethylene glycol (PEG), the addition of ammonium acetate into urea–nitrates system results in numerous ignition points and uniform propagation of flames in gas–phase, which is conducive to the formation of small and dispersive NiO particles. Moreover, thermal analysis reveals that ammonium acetate, benefiting from its simultaneous decomposition with urea and metal nitrates as well as endothermic characteristic, serves as an inhibitor in combustion system that adsorbs the combustion heat to prevent the agglomeration of NiO particles. As a result, the optimum Ni–Al2O3 catalyst retains an desirable CO conversion of 92% and CH4 selectivity of 86% toward methane synthesis via slurry phase CO methanation at 260°C, 1.0MPa and 6000mL/gcat·h within 50h. Taking ammonium acetate as a fuel additive, a solution combustion synthetic fashion is expected to optimize the nanostructure and activity of Ni–Al2O3 catalyst.
      Graphical abstract image

      PubDate: 2017-01-28T14:57:21Z
      DOI: 10.1016/j.apcata.2017.01.016
      Issue No: Vol. 534 (2017)
       
  • Potassium promotion on CO hydrogenation on the χ-Fe5C2(111) surface
           with carbon vacancy
    • Authors: Shu Zhao; Xing-Wu Liu; Chun-Fang Huo; Yong-Wang Li; Jianguo Wang; Haijun Jiao
      Pages: 22 - 29
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Shu Zhao, Xing-Wu Liu, Chun-Fang Huo, Yong-Wang Li, Jianguo Wang, Haijun Jiao
      The mechanisms of CO hydrogenation with the formation of C1 surface species on the clean and K2O-doped χ-Fe5C2(111) surfaces with carbon vacancies have been comparatively elucidated. On both surfaces, CO direct dissociation (CO→C+O) is not favored. On the clean surface, the preferred H-assisted pathway is CO→HCO→CH2O→CH3O→CH3OH. On the K2O-doped surface, the preferred paths are HCO→CHOH→CH+OH and HCO→CH2O→CH2OH→CH2 +OH due to the barrier decrease of the CO bond cleavage of COH, CHOH and CH2OH by K2O promotion. These results might explain the K2O promoted carburization process and the formation of long-chain hydrocarbons.
      Graphical abstract image

      PubDate: 2017-01-28T14:57:21Z
      DOI: 10.1016/j.apcata.2017.01.012
      Issue No: Vol. 534 (2017)
       
  • Facile fabrication of N-doped three-dimensional reduced graphene oxide as
           a superior electrocatalyst for oxygen reduction reaction
    • Authors: Yi Li; Juan Yang; Na Zhao; Jipei Huang; Yazhou Zhou; Kai Xu; Nan Zhao
      Pages: 30 - 39
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Yi Li, Juan Yang, Na Zhao, Jipei Huang, Yazhou Zhou, Kai Xu, Nan Zhao
      Nitrogen-doped graphene materials provide the attractive potentials to replace the high-priced Pt and Pt-based catalysts for oxygen reduction reaction (ORR) to accelerate the industrialization of fuel cells (FCs). Herein, the nitrogen-doped three-dimensional reduced graphene oxide (N-3DrGO) catalysts have been prepared by a facile hydrothermal method using the raw materials of GO, melamine and formaldehyde. The N contents in N-3DrGO products vary from 3.12 to 9.69 at.% which can be easily regulated by adjusting the feed mass ratios of GO and melamine. It is found that a higher content of N does not necessarily result in enhanced electrocatalytic activity. Rather, with the highest total percentage of graphitic N and pyridinic N (69.2%), superior solvent dispersibility, as well as a smaller interfacial and charge-transfer resistance, the N-3DrGO catalyst obtained by a mass ratio of 1:1.5 between GO and melamine presents the most excellent activity towards ORR. As a catalyst using in FCs for ORR, the obtained N-3DrGO catalysts exhibit favorable electrocatalytic performance, excellent methanol tolerance and much enhanced durability compared with that of commercial Pt/C (20wt%) catalyst in alkaline media. Furthermore, the above-mentioned approach is demonstrated to be a versatile method in fabricating N-3DrGO-based catalysts by introducing the foreign active atoms such as sulfur (S) to realize the N and S co-doping, which can further enhance the catalysts’ ORR activity.
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      PubDate: 2017-01-28T14:57:21Z
      DOI: 10.1016/j.apcata.2017.01.014
      Issue No: Vol. 534 (2017)
       
  • One-step Pd/C and Eu(OTf)3 catalyzed hydrodeoxygenation of branched C11
           and C12 biomass-based furans to the corresponding alkanes
    • Authors: Juha Keskiväli; Pauli Wrigstedt; Kalle Lagerblom; Timo Repo
      Pages: 40 - 45
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Juha Keskiväli, Pauli Wrigstedt, Kalle Lagerblom, Timo Repo
      Solvent-free NaOH catalyzed aldol condensation of biomass-derived 5-hydroxymethyl furfural (HMF) and furfural with methyl isobutyl ketone (MIBK) was studied, producing branched C11 and C12 furan compounds in high yields of up to 96%. Through use of a Pd/C and Eu(OTf)3 catalytic system, the condensation products of the bio-based starting materials were further hydrodeoxygenated (HDO) in one-step to biofuel compatible branched alkanes 2-methylundecane (3) and 2-methyldecane (4) in excellent yields of 90% and 98%, respectively. In the one-step HDO developed herein, the variation of solvent had a significant effect on the reaction route and degree of conversion of furans to alkanes in the HDO process. Very high overall yields of alkanes 3 (86%) and 4 (94%) were obtained starting from the biomass-based HMF and furfural.
      Graphical abstract image

      PubDate: 2017-01-28T14:57:21Z
      DOI: 10.1016/j.apcata.2017.01.017
      Issue No: Vol. 534 (2017)
       
  • Lattice distortion induced electronic coupling results in exceptional
           enhancement in the activity of bimetallic PtMn nanocatalysts
    • Authors: Xin Jin; Chun Zeng; Wenjuan Yan; Meng Zhao; Pallavi Bobba; Honghong Shi; Prem S. Thapa; Bala Subramaniam; Raghunath V. Chaudhari
      Pages: 46 - 57
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Xin Jin, Chun Zeng, Wenjuan Yan, Meng Zhao, Pallavi Bobba, Honghong Shi, Prem S. Thapa, Bala Subramaniam, Raghunath V. Chaudhari
      Lattice strain plays a critical role in structural heterogeneity and surface electronic properties of bimetallic nanocatalysts. However, understanding of how to engineer optimal electron transfer in anisotropic bimetallic crystals remains a grand challenge to achieve enhanced catalytic performances. We investigate beyond conventional polymer based core-shell and alloy structures, and present unique lattice distorted PtMn catalysts fabricated via a cooperative self-assembly method. The strong internal strain between Pt and Mn lattices is found to induce the structural distortion of anisotropic PtMn crystals and formation of asymmetric flower shapes, leading to stretched Pt and contracted Mn lattices. Such distorted bimetallic crystals exhibit unusual electronic coupling and an eight-fold synergistic enhancement in catalytic oxidation of renewable biomass feedstocks compared with monometallic Pt catalysts. The novel synthesis technique and revealed electronic coupling mechanism described herein opens the door for the rational discovery of other bimetallic nanocatalysts with positive synergy.
      Graphical abstract image

      PubDate: 2017-02-04T23:56:49Z
      DOI: 10.1016/j.apcata.2017.01.021
      Issue No: Vol. 534 (2017)
       
  • Effect of Bi on catalytic performance and stability of MoVTeNbO catalysts
           in oxidative dehydrogenation of ethane
    • Authors: E.V. Ishchenko; R.V. Gulyaev; T.Yu. Kardash; A.V. Ishchenko; E.Yu. Gerasimov; V.I. Sobolev; V.M. Bondareva
      Pages: 58 - 69
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): E.V. Ishchenko, R.V. Gulyaev, T.Yu. Kardash, A.V. Ishchenko, E.Yu. Gerasimov, V.I. Sobolev, V.M. Bondareva
      Catalysts with the Mo1V0.3Te0.23Nb0.12Bi0-0.05 compositions were prepared via spray-dry method and tested in ethane oxidative dehydrogenation (ODE) reaction. The catalysts were characterized by XRD, HRTEM, SEM and XPS. A strong effect of the bismuth content on physicochemical and catalytic properties was observed. At low Bi concentrations (Bi/Mo=0.004–0.075) the M1/M2 ratio, morphology and dispersity of the M1 phase changed resulting in a decrease of the catalytic activity. The maximum activity, selectivity to ethylene and stability in reaction conditions were obtained at intermediate Bi concentrations (Bi/Mo=0.015–0.025). These samples had the highest M1 amount among modified samples. Hindering of Te segregation along six-membered channels of the M1 phase preventing the Te loss was detected. Bi incorporation in such channels and its possible participation in active ensembles are assumed to be responsible both for the stability and enhanced catalytic properties of the M1 phase. A further increase of the bismuth content (Bi/Mo=0.05) was accompanied by a decrease of the M1 particle size and structural disordering. Suppression of the M1 phase crystallization and formation of less active and selective M2 and M5O14 phases (M-Mo,V,Nb) were observed at the maximum bismuth content.
      Graphical abstract image

      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.01.023
      Issue No: Vol. 534 (2017)
       
  • High-surface-area, iron-oxide films prepared by atomic layer deposition on
           γ-Al2O3
    • Authors: Tzia Ming Onn; Matteo Monai; Sheng Dai; Lisandra Arroyo-Ramirez; Shuyi Zhang; Xiaoqing Pan; George W. Graham; Paolo Fornasiero; Raymond J. Gorte
      Pages: 70 - 77
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Tzia Ming Onn, Matteo Monai, Sheng Dai, Lisandra Arroyo-Ramirez, Shuyi Zhang, Xiaoqing Pan, George W. Graham, Paolo Fornasiero, Raymond J. Gorte
      High-surface-area iron oxides were prepared by Atomic Layer Deposition (ALD) on 130-m2/g γ-Al2O3 for use as a catalyst support. Measurements of the sample mass, surface area, and pore-size distribution as a function of the number of ferrocene-O2 ALD cycles at 623K suggested that the iron oxide grew as a dense, conformal film with a growth rate similar to 0.016-nm per cycle. While films with 20 ALD cycles (20Fe2O3-Al2O3, 0.25g Fe2O3/g Al2O3) were difficult to distinguish by HAADF STEM, EDS mapping indicated the Al2O3 was uniformly coated. Raman Spectroscopy showed the films were in the form of Fe2O3; but XRD measurements on samples with as many as 100 ALD cycles (100Fe2O3-Al2O3, 0.84g Fe2O3/g Al2O3) showed no evidence for crystalline iron-oxide phases, even after calcination at 1073K. Specific rates for the water-gas-shift (WGS) reaction on the ALD-coated samples were significantly lower than those on bulk Fe2O3. However, addition of 1wt.% Pd to Fe2O3/Al2O3 supports prepared by ALD exhibited specific rates that were much higher than that observed when 1wt.% Pd was added to Fe2O3/Al2O3 prepared by conventional impregnation of Fe salts, suggesting more uniform contact between the Pd and FeOx phases on samples prepared by ALD.
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      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.01.025
      Issue No: Vol. 534 (2017)
       
  • Durability of catalytic performance of the chlorine-doped catalyst
           Ni(Clx)/ZrO2 for selective methanation of CO in H2-rich gas
    • Authors: Zhiming Gao; Linlin Wang; Hongwei Ma; Zhanping Li
      Pages: 78 - 84
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Zhiming Gao, Linlin Wang, Hongwei Ma, Zhanping Li
      Chlorine-doped catalysts Ni(Clx)/ZrO2 (x =0.0–0.6) were prepared for selective methanation of CO in H2-rich gas (CO-SMET). Effects of chlorine ions were studied by means of X-ray diffraction (XRD), temperature programmed reduction (TPR) and adsorption measurements. It is found that chlorine ions could promote Ni crystallite growth and suppress CO2 adsorption. As a result, a deep removal of CO to below 10ppm was achieved with a high selectivity of more than 50% in a wide reaction temperature range. And, at the reaction temperature of 220°C, the selectivity of CO methanation kept at 100% with CO outlet concentration below 10ppm in the 100h durability test over the catalyst Ni(Cl0.1)/ZrO2. However, the selectivity decreased with reaction time at the higher reaction temperatures of 240°C and 280°C. Both X-ray fluorescence spectroscopy (XRF) analysis and ion chromatography analysis proved that chlorine ions evolved in the catalytic reaction, which then allowed for more CO2 to be adsorbed on the catalyst and hydrogenated into methane. This finally resulted in the decrease of the selectivity of CO methanation.
      Graphical abstract image

      PubDate: 2017-02-17T08:56:17Z
      DOI: 10.1016/j.apcata.2017.02.001
      Issue No: Vol. 534 (2017)
       
  • SO2 adsorption and desorption characteristics of Pd and Pt catalysts:
           Precious metal crystallite size dependence
    • Authors: Monique Shauntá Wilburn; William S. Epling
      Pages: 85 - 93
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Monique Shauntá Wilburn, William S. Epling
      SO2 adsorption and desorption on Pt/Pd mono- and bimetallic, γ-Al2O3 supported catalysts were characterized. There are dependencies on both particle size and Pd:Pt ratio, and here particle size effects on the adsorption and desorption trends and surface species formed were evaluated using DRIFTS and TPD studies. Catalysts with a smaller particle size tended to form a greater amount of aluminum sulfate species, which decomposed at high-temperature. In contrast, catalysts with larger particle sizes tended to form a greater amount of low-temperature decomposing and desorbing species, such as molecular SO2 and surface aluminum sulfite. In general, it was found that the amount of SO2 adsorbed and later desorbed during TPD decreased with increasing particle size.
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      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.01.015
      Issue No: Vol. 534 (2017)
       
  • Ferrite catalysts derived from electroplating sludge for high-calorie
           synthetic natural gas production
    • Authors: Min Chen; Jizhi Zhou; Jia Zhang; Juan Zhang; Zheng Chen; Jian Ding; Fanhua Kong; Guangren Qian; Jiangang Chen
      Pages: 94 - 100
      Abstract: Publication date: 25 March 2017
      Source:Applied Catalysis A: General, Volume 534
      Author(s): Min Chen, Jizhi Zhou, Jia Zhang, Juan Zhang, Zheng Chen, Jian Ding, Fanhua Kong, Guangren Qian, Jiangang Chen
      In this study, a ferrite catalyst has been prepared through a facile hydrothermal method using industrial Zn and Fe-rich electroplating sludge as raw materials and utilized for the first time as an efficient catalyst for methanation of syngas. The ferrite catalyst showed pretty good catalytic performance during the stability test at 340°C for 300h, meanwhile exhibited a higher resistance to thermal shock (600°C for 12h) than that of the catalyst prepared from pure chemical reagents or commercial methanation catalyst. More importantly, a high-calorie natural gas with heating value of 41.73MJNm−3 could be obtained via methanation of syngas over the ferrite catalyst derived from electroplating sludge. Thus, this work provides some new insights for utlising solid waste as raw material for methanation catalyst, which is very cheap.
      Graphical abstract image

      PubDate: 2017-02-11T00:09:41Z
      DOI: 10.1016/j.apcata.2017.01.022
      Issue No: Vol. 534 (2017)
       
  • Catalytic performance of metal azolate frameworks in the solventless
           synthesis of cyclic carbonates from CO2 and epoxides
    • Authors: Han-Ung Kim; Robin Babu; Roshith Roshan; Dae-Won Park
      Abstract: Publication date: Available online 20 March 2017
      Source:Applied Catalysis A: General
      Author(s): Han-Ung Kim, Robin Babu, Roshith Roshan, Dae-Won Park
      Two types of metal azolate frameworks (MAFs) with uncoordinated and coordinated nitrogen atoms composed of zinc coordinated with 3-amino-1,2,4-triazole and 3,5-dimethyl-1,2,4-triazole linkers denoted as MAF-66 and MAF-X5, respectively have been synthesized and characterized using various physicochemical techniques. The uncoordinated N donors present in the MAFs show high adsorption affinity for carbon dioxide. The synthesized MAFs showed promising catalytic activity towards the cycloaddition of carbon dioxide and epoxides under solvent-free conditions with excellent selectivity towards the desired five-membered cyclic carbonates. The importance of uncoordinated N donors and amine groups in the effective catalysis of the cycloaddition of CO2 and epoxides was investigated. Both catalysts were separable by simple filtration and reusable without any considerable loss in the initial activity. Various reaction parameters including temperature, reaction time, and CO2 pressure were studied. A possible reaction mechanism explaining the role of amine groups in the cycloaddition reaction was proposed based on literature and experimental inferences.
      Graphical abstract image

      PubDate: 2017-03-21T08:28:03Z
      DOI: 10.1016/j.apcata.2017.03.028
       
  • Visible light responsive TiO2 nanoparticles modified using Ce and La for
           photocatalytic reduction of CO2: Effect of Ce dopant content
    • Authors: Khozema Ahmed Ali; Ahmad Zuhairi Abdullah; Abdul Rahman Mohamed
      Abstract: Publication date: Available online 20 March 2017
      Source:Applied Catalysis A: General
      Author(s): Khozema Ahmed Ali, Ahmad Zuhairi Abdullah, Abdul Rahman Mohamed
      Photocatalytic reduction of CO2 in aqueous solution was performed using TiO2 photocatalysts modified with Ce and La under fluorescent light irradiation. The photocatalysts were prepared using modified sol gel method with Ce doping content varied between 0–2 wt%. Comprehensive characterization using XRD, XPS, nitrogen physisorption, SEM, EDX, PL and UV- vis spectroscopy revealed that the introduction of cerium affected the surface, structural and optical properties of the photocatalyts. Among all the doped photocatalysts, 1.5wt% Ce/La/TiO2 showed the highest photocatalytic activity under fluorescent light irradiation. In the liquid phase, a maximum yield of 317.7μmol/g-cat for CH3OH was achieved whereas CH4 and CO were the main products in the gas phase with maximum yields of 262.8 and 119.4μmol/g-cat, repsectively. The addition of Ce and La was found to inhibit the growth of anatase TiO2, increase the surface area and improve the optical properties of the photocatalyst. The existence of Ce3+/Ce4+ mixture was also found to effectively inhibit the electron-hole recombination, enhancing the photocatalytic activity of Ce/La co-doped TiO2.
      Graphical abstract image

      PubDate: 2017-03-21T08:28:03Z
      DOI: 10.1016/j.apcata.2017.03.022
       
  • Bimetallic Au-Cu Alloy Nanoparticles on Reduced Graphene Oxide Support:
           Synthesis, Catalytic Activity and Investigation of Synergistic Effect by
           DFT Analysis
    • Authors: Lipeeka Rout; Aniket Kumar; Rajendra S. Dhaka; G.Naresh Reddy; Santanab Giri; Priyabrat Dash
      Abstract: Publication date: Available online 19 March 2017
      Source:Applied Catalysis A: General
      Author(s): Lipeeka Rout, Aniket Kumar, Rajendra S. Dhaka, G.Naresh Reddy, Santanab Giri, Priyabrat Dash
      Highly active and well defined Au-Cu nanoparticles supported on reduced graphene oxide (rGO) were synthesized by a simple and one-step deposition-precipitation method. The nanoparticles were thoroughly characterized by UV-Visible, X-ray diffraction (XRD), High resolution transmission electron microscope (HRTEM), scanning transmission electron microscope (STEM) with line scanning and line mapping energy dispersive X-ray spectroscopy (EDS), Raman and X-ray photoelectron spectroscopy (XPS). The composition dependant catalytic activity for the synthesized catalyst was evaluated in the reduction of 4-nitrophenol (4-NP). Among different metal and bimetallic Au-Cu compositions, Au3-Cu1 exhibited highest activity with rate constant of 96×10−3 sec−1, which is superior to all other reported work. Within the density functional theory framework, theoretical investigations of our catalyst were carried out to find the reason behind its superior catalytic activity. It has been found that unique synergistic effect between the highly dispersed Au-Cu nanoparticles and rGO support helps in the efficient adsorption of 4-NP on Au3-Cu1/rGO catalyst, highlighting the importance of hybrid bimetallic nanoparticle-GO structure for enhanced catalytic activity. Moreover, effect of various support materials such as activated carbon and alumina was studied on the catalytic activity of Au-Cu nanoparticles. In addition, our catalyst demonstrated excellent activity for the reduction of toxic azo dyes (congo red, methyl orange, and erichrome black T), demonstrating its ability for multiple reduction reactions. Moreover, the efficient removal of the produced amines after the reduction reaction was demonstrated via a convenient waste management strategy using an industrial solid waste red mud. Our results will lead to the possibility of designing suitable GO-based bimetallic system with superior catalytic performance in environmental remediation applications.
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      PubDate: 2017-03-21T08:28:03Z
      DOI: 10.1016/j.apcata.2017.03.017
       
  • Glycidol hydrogenolysis on a cheap mesoporous acid saponite supported Ni
           catalyst as alternative approach to 1,3-propanediol synthesis
    • Authors: F.B. Gebretsadik; J. Ruiz-Martinez; P. Salagre; Y. Cesteros
      Abstract: Publication date: Available online 19 March 2017
      Source:Applied Catalysis A: General
      Author(s): F.B. Gebretsadik, J. Ruiz-Martinez, P. Salagre, Y. Cesteros
      This study explores the use of glycidol, as alternative to glycerol, to improve the selectively to 1,3-propanediol (PrD) by hydrogenolysis. The reaction was performed using Ni (with different Ni wt %) supported on an acid delaminated saponite catalysts which are cheaper compared to the expensive catalysts needed to favor the 1,3-PrD formation by glycerol hydrogenolysis. An increase in metallic area and a decrease in the catalyst acidity resulted in higher conversion and selectivity to propanediols (1,2-+1,3-PrD). An acid activation of glycidol during hydrogenolysis promoted the 1,3-PrD formation and increased the 1,3-PrD/1,2-PrD ratio. For the catalyst prepared with 40wt % Ni loading, an increase in the reaction temperature to 423 and 453K led to higher 1,3-PrD/1,2-PrD ratio. The highest 1,3-PrD yield (29%) and 1,3-PrD/1,2-PrD ratio (0.97) at total conversion were obtained at 453K, after 1h. The overall 1,3-PrD yield from glycerol, assuming a two-step synthesis (Glycerol→Glycidol→1,3-PrD) and a yield of 78% for the first step, should be around 23%. This value is comparable to that reported for the hydrogenolysis of glycerol using noble metal catalysts.
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      PubDate: 2017-03-21T08:28:03Z
      DOI: 10.1016/j.apcata.2017.03.018
       
  • Catalytic upgrading of furfuryl alcohol to bio-products: Catalysts
           screening and kinetic analysis
    • Authors: M. Paniagua; J.A. Melero; J. Iglesias; G. Morales; B. Hernández; C. López-Aguado
      Abstract: Publication date: Available online 6 March 2017
      Source:Applied Catalysis A: General
      Author(s): M. Paniagua, J.A. Melero, J. Iglesias, G. Morales, B. Hernández, C. López-Aguado
      The conversion of furfuryl alcohol, a highly versatile biomass-derived platform molecule, into a large variety of bio-products, including ethers, lactones and levulinates, has been evaluated in alcohol media using different solid acid catalysts, such as commercial zeolites, sulfonic acid-functionalized materials, and sulfated zirconia. Reaction pathways and mechanisms have been correlated to the particular type of catalyst used, aiming to establish the influence of the main physico-chemical properties of the materials on the extent of furfuryl alcohol conversion, as well as on the predominant reaction pathway followed. Mechanistic and kinetics modelling studies for each type of catalyst have been developed and compared, providing an useful tool for the selection of the most suitable solid acid catalyst for the production of each of the reaction intermediates in the cascade from furfuryl alcohol to alkyl levulinate.
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      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.03.004
       
  • Dehydration of sorbitol to isosorbide over sulfonic acid resins under
           solvent-free conditions
    • Authors: María José Ginés Molina; Ramón Moreno-Tost; José Santamaría-González; Pedro Maireles-Torres
      Abstract: Publication date: Available online 6 March 2017
      Source:Applied Catalysis A: General
      Author(s): María José Ginés Molina, Ramón Moreno-Tost, José Santamaría-González, Pedro Maireles-Torres
      Different commercial sulfonic acid resins (Purolite and Amberlyst type) have been evaluated as acid catalysts for the dehydration of sorbitol to isosorbide. These acidic resins differ in their acid properties, as well as in their thermal and mechanical stabilities. Dehydration of sorbitol has been carried out under solvent-free conditions, by melting sorbitol. At the beginning of reaction, different sorbitans (monodehydration products) were detected, whose dehydration and subsequent cyclization lead to the formation of isosorbide. A maximum yield of 75% is reached after 12h at 413K, by using a 5wt% of Purolite CT269, at atmospheric pressure. This resin maintains its catalytic activity after four runs, and the stability is corroborated by the negligible presence of sulphur species (coming from sulfonic acid leaching) in the reaction medium. This suitable catalytic performance can be explained by its high acid capacity (5.2meqg−1) and mechanical and thermal stabilities associated to the macroreticular structure.
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      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.03.006
       
  • Skeletal Isomerization of n-Pentane: A Comparative Study on Catalytic
           Properties of Pt/WOx−ZrO2 and Pt/ZSM-22
    • Authors: Wei Li; Kebin Chi; Hao Liu; Huaijun Ma; Wei Qu; Congxin Wang; Guang Lv; Zhijian Tian
      Abstract: Publication date: Available online 6 March 2017
      Source:Applied Catalysis A: General
      Author(s): Wei Li, Kebin Chi, Hao Liu, Huaijun Ma, Wei Qu, Congxin Wang, Guang Lv, Zhijian Tian
      Pt/WO x −ZrO2 and Pt/ZSM-22 were prepared and used as catalysts for the n-pentane hydroisomerization reactions. The physico-chemical properties of the supports were characterized by XRD, N2 adsorption, NH3-TPD and 1-pentene isomerization reaction. The reducibility and adsorbability of the catalysts were evaluated via H2-TPR, H2-TPD and CO adsorption. Under the reaction condition of WHSV=1h−1, pn -pentane,0 =0.24bar and ambient pressure, the yields of isopentane over Pt/WO x −ZrO2 and Pt/ZSM-22 can reach 52% (at 300°C) and 61% (at 340°C) respectively. The selectivities to isopentane over these two catalysts are well above 95%. The hydroisomerization mechanisms over these catalysts are discussed.
      Graphical abstract image

      PubDate: 2017-03-09T13:30:15Z
      DOI: 10.1016/j.apcata.2017.03.005
       
  • Kinetic modelling of temperature-programmed reduction of cobalt oxide by
           hydrogen
    • Authors: Chao’en Li; Lisa Wong; Liangguang Tang; Nicola V.Y. Scarlett; Ken Chiang; Jim Patel; Nick Burke; Valerie Sage
      Abstract: Publication date: Available online 3 March 2017
      Source:Applied Catalysis A: General
      Author(s): Chao’en Li, Lisa Wong, Liangguang Tang, Nicola V.Y. Scarlett, Ken Chiang, Jim Patel, Nick Burke, Valerie Sage
      The reduction activities and mechanisms of cobalt-based catalysts are of great interest to industry and researchers, due to their applications in Fischer–Tropsch synthesis. Here, we investigated the reduction of alumina‐supported cobalt catalysts by hydrogen using temperature-programmed reduction. We propose a five-step reduction mechanism that incorporates both amorphous and crystalline Co3O4, and includes the interaction between CoO and the Al2O3 support. Based on our proposed mechanism, we developed a kinetic model of the reduction process. The modelling results of catalysts promoted with ruthenium and lanthanum in contrast with un-promoted catalyst clearly show that the promoter improves reducibility of the catalyst. The effect of Co3O4 crystallinity was also investigated by the reduction of fresh in comparison of pre-oxidised catalyst. We conclude that high crystallinity significantly increases the difficulty of reducing Co3O4. The interaction between CoO and Al2O3 under reduction conditions to form CoAl2O4 was quantitatively simulated. The kinetic modelling confirms that the support plays an important role in catalyst reduction via the interaction between the catalyst and the support. Those kinetic modelling results are supported by in situ X-ray diffraction studies of the reduction process.
      Graphical abstract image

      PubDate: 2017-03-03T13:30:13Z
      DOI: 10.1016/j.apcata.2017.02.022
       
 
 
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