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  Subjects -> ENGINEERING (Total: 2270 journals)
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ENGINEERING (1199 journals)                  1 2 3 4 5 6 | 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: 15)
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: 216)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
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)
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Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
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Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
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Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
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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)
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Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 27)
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: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 8)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
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Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
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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: 8)
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: 23)
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: 9)
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: 3)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 38)
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: 13)
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: 3)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
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: 3)
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: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 21)
Clay Minerals     Full-text available via subscription   (Followers: 9)
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: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 4)
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: 6)
Composite Structures     Hybrid Journal   (Followers: 252)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 177)
Composites Part B : Engineering     Hybrid Journal   (Followers: 222)
Composites Science and Technology     Hybrid Journal   (Followers: 165)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
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Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
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Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
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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: 8)
Control Engineering Practice     Hybrid Journal   (Followers: 41)
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  

        1 2 3 4 5 6 | Last

Journal Cover Applied Catalysis A: General
  [SJR: 1.234]   [H-I: 159]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0926-860X
   Published by Elsevier Homepage  [3031 journals]
  • Deactivation study of carbon-supported ruthenium catalyst with potassium
           promoter
    • Authors: Bingyu Lin; Yunjie Guo; Jingdong Lin; Jun Ni; Jianxin Lin; Lilong Jiang; Yong Wang
      Pages: 1 - 7
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Bingyu Lin, Yunjie Guo, Jingdong Lin, Jun Ni, Jianxin Lin, Lilong Jiang, Yong Wang
      Carbon-supported Ru catalyst with alkali promoter is arguably the most significant advancement in ammonia synthesis. However, the insufficient stability of this type of catalysts greatly limits their applications, and carbon methanation is often considered as the reason for deactivation. Here we report that there is no clear correlation between carbon methanation and the loss of activity. Rather, carbon oxidation at high temperature, especially via the formation of carbon monoxide, was found to have a strong influence on the activity and stability of Ru catalysts. As a result, there is a significant increase in carbon loss, leading to the sintering of Ru particles and thereby altered hydrogen adsorption. Consequently, catalytic activity and stability of Ru/C catalysts are reduced. This finding contributes to the development of strategies to design carbon-supported metal catalysts with high activity and stability.
      Graphical abstract image

      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.020
      Issue No: Vol. 541 (2017)
       
  • A DFT study of ethane activation on IrO2(110) surface by
           precursor-mediated mechanism
    • Authors: Thong Le Minh Pham; Santhanamoorthi Nachimuthu; Jer-Lai Kuo; Jyh-Chiang Jiang
      Pages: 8 - 14
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Thong Le Minh Pham, Santhanamoorthi Nachimuthu, Jer-Lai Kuo, Jyh-Chiang Jiang
      The adsorption configurations of ethane on IrO2(110) surface have been investigated using density functional theory (DFT) methods. We find that ethane is most stably adsorbed on IrO2(110) surface by interacting with two adjacent Ircus atoms, which is mainly driven by agostic interaction. We have also performed an elementary step analysis for the ethane dehydrogenation via precursor mediated mechanism on IrO2(110) surface. Our results indicate that the activation of ethane on IrO2(110) surface is both thermodynamically and kinetically favorable reaction, which is expected to occur at low temperature. Further, we have investigated the role of van der Walls corrections on adsorption and the reaction energetics of ethane dehydrogenation. The results indicate that the contribution of van der Walls corrections has a major impact on ethane adsorption and it facilitates the ethane activation via precursor mediated mechanism instead of desorption.
      Graphical abstract image

      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.018
      Issue No: Vol. 541 (2017)
       
  • Catalytic oxidative dehydrogenation of carveol to carvone over the
           phthalocyanine complex FePcCl16 immobilized on the mesoporous silica
           SBA-15
    • Authors: Diana-Lucía Grajales; Lina-María González; Aída-Luz Villa
      Pages: 15 - 24
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Diana-Lucía Grajales, Lina-María González, Aída-Luz Villa
      The immobilization of the FePcCl16 complex on the mesoporous silica SBA-15 and its performance in the eco-friendly oxidative dehydrogenation of carveol to carvone in the presence of t-butyl hydroperoxide (TBHP) under mild conditions is reported. The successful covalently anchored of FePcCl16 complex inside the pores of SBA-15, without complex or support damage, was confirmed by XRD, BET, UV–vis, SEM, TEM and Raman analysis. The best results achieved were after 1h of reaction, with 40% carvone selectivity and a carveol conversion around of 75%; carvone selectivity decayed when carveol conversion increased. Several mechanisms and rate equations derived from the kinetic models based on the Power Law, Langmuir-Hinshelwood, and Eley-Rideal model were proposed. Although the Power Law model showed the best mathematical fitting, the Eley-Rideal model seems to explain better the chemical sense of reaction. FePcCl16-NH2-SBA-15 catalyst was stable under the reaction conditions and it can be used up to twice without significant decrease in its catalytic activity.
      Graphical abstract image

      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.019
      Issue No: Vol. 541 (2017)
       
  • Biphasic TiO2 microspheres/reduced graphene oxide for effective
           simultaneous photocatalytic reduction and oxidation processes
    • Authors: Hanan H. Mohamed
      Pages: 25 - 34
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Hanan H. Mohamed
      Simultaneous photoassisted oxidation of organic dyes (methylene blue (MB), crystal violet (CV)) and reduction of metal ions (Ag(I), Cu(II)) were studied using new synthesized hierarchical structures of anatase/rutile TiO2 microspheres-reduced graphene oxide (TiO2-rGO) nanocomposites. Interestingly, rutile/anatase phase transformation was observed upon changing the graphene oxide content. An increasing of the anatase/rutile ratio upon increasing the graphene oxide content was observed. Additionally, the synthesized nanocomposites show enhanced photocatalytic activity either for the reduction of heavy metal ions or for the degradation of the dyes compared to pristine TiO2 nanoparticles. A highest activity has been achieved using the nanocomposite containing 62% anatase and 38% rutile. This enhancement in the photocatalytic activity can be attributed to the synergetic effect between anatase and rutile in the synthesized TiO2 microspheres composites. Furthermore, The study of the effect of various concentrations of metal ions shows that increasing the metal ions concentration highly promoted the photocatalytic degradation of the organic dyes. A complete decoloration of both dyes has been observed within very short time. Furthermore, enhancement of the photocatalytic reduction of the metal ions was achieved by increasing the dye concentration. Therefore, an obvious synergistic effect was observed leading to the enhancement of both the photocatalytic and reduction. The results show a cost effective method for a simultaneous removal of organic and inorganic pollutants from wastewater.
      Graphical abstract image

      PubDate: 2017-05-12T16:26:40Z
      DOI: 10.1016/j.apcata.2017.04.017
      Issue No: Vol. 541 (2017)
       
  • Use of tetraethylammonium bicarbonate as a precipitation agent on the
           preparation of coprecipitated Cu/ZnO catalysts
    • Authors: Cheonwoo Jeong; Taewoo Kim; Jinsung Kim; Young-Woong Suh
      Pages: 35 - 41
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Cheonwoo Jeong, Taewoo Kim, Jinsung Kim, Young-Woong Suh
      Cu/ZnO catalysts were prepared by coprecipitation using tetraethylammonium bicarbonate (TEA+HCO3 −), and their properties and methanol synthesis activities were compared to those of the catalysts prepared using Na+HCO3 − usually employed for commercial Cu/ZnO/(Al2O3) catalysts. When washed fully, TEA+- and Na+-based precursors showed typical zincian malachite (zM) without any other structures, and both catalysts obtained after calcination and H2 reduction exhibited the similar specific copper surface area and, in turn, the similar methanol productivity. Since this result explains that TEA+ does not affect zM structure if Cu,Zn precipitate is fully washed, no washed and less washed TEA+- and Na+-based precursors were prepared. It was interesting that all TEA+-based catalysts exhibited the similar methanol productivity irrespective of the washing efficiency whereas Na+-based catalyst containing more residual Na+ showed the smaller copper surface area and lower methanol productivity (i.e., linear correlation between the two parameters). This resulted from the inhibiting effect of Na+ on the degree of Cu2+ substitution by Zn2+ and the formation of high-temperature carbonate, consequently leading to a lower catalytic activity. These negative effects of Na+ were absent or lessened when TEA+HCO3 − was used as a precipitation agent, which is effective in preparing an active methanol synthesis catalyst.
      Graphical abstract image

      PubDate: 2017-05-12T16:26:40Z
      DOI: 10.1016/j.apcata.2017.04.023
      Issue No: Vol. 541 (2017)
       
  • Simultaneous removal of soot and NOx with Ru-Ir/TiO2 catalyst under
           oxygen-rich condition
    • Authors: Rongshu Zhu; Qingyun Yan; Jiansheng He; Gang Cao; Feng Ouyang
      Pages: 42 - 49
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Rongshu Zhu, Qingyun Yan, Jiansheng He, Gang Cao, Feng Ouyang
      A series of Ru-Ir bimetallic catalysts with different mass ratios (Ru-Ir/TiO2, Ru:Ir=9:1, 7:3, 5:5, 3:7, 1:9) were prepared by iso-volumetric impregnation method. The activities of the catalysts for simultaneous removal of soot and NOx were investigated by Temperature Programmed Surface Reaction (TPSR) technique, and the properties of the catalysts were characterized by various analysis techniques, such as XPS, XRD, TEM, H2-TPR, H2-TPD and nitrogen adsorption. The results indicated that Ru-Ir/TiO2 bimetallic catalysts had better activity for simultaneous removal of soot and NOx than Ru/TiO2 or Ir/TiO2. When the mass ratio of Ru:Ir was 9:1, the catalyst showed the best catalytic activity. The peak temperature of soot oxidation was 437°C and the highest conversion efficiency of NOx was 42.6%. On the basis of the characterization of the catalysts, the relationship between the catalytic activity of Ru-Ir/TiO2 and the synergetic roles of Ru and Ir was discussed.
      Graphical abstract image

      PubDate: 2017-05-12T16:26:40Z
      DOI: 10.1016/j.apcata.2017.04.014
      Issue No: Vol. 541 (2017)
       
  • Fischer-Tropsch synthesis to light olefins over iron-based catalysts
           supported on KMnO4 modified activated carbon by a facile method
    • Authors: Zhipeng Tian; Chenguang Wang; Zhan Si; Longlong Ma; Lungang Chen; Qiying Liu; Qi Zhang; Hongyu Huang
      Pages: 50 - 59
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Zhipeng Tian, Chenguang Wang, Zhan Si, Longlong Ma, Lungang Chen, Qiying Liu, Qi Zhang, Hongyu Huang
      Fischer-Tropsch synthesis to light olefins (FTO) using biomass-derived syngas is an economical and renewable way to produce olefins. By using KMnO4 as precursor, a number of low cost iron based catalysts was produced and their FTO performances were tested. Firstly, a series of KMnO4 solutions with different concentrations were used to pretreat activated carbon (AC). Support was coated uniformly by K-doped birnessite MnO2 and substantial amount of surface oxygen-containing groups and defects were obtained simultaneously. Then, iron catalysts loaded on KMnO4 modified AC support was prepared by incipient wetness impregnation method. Characterization of the catalyst showed that α-Fe2O3 nanoparticles were uniformly loaded on the surface of KMnO4 treated AC. The valent of manganese (IV) was then transformed into Mn (II) and Mn (III) with AC served as a reducing agent. The redox reaction during preparation leads to a lower Mn chemical valence, which makes it easier to further reduction. More defects on support after calcination procedure were also observed due to the enrichment of oxygen-containing groups, which was helpful in anchoring α-Fe2O3 particles and decreasing its average particle size. High-content manganese played not only as a structural promoter to anchor Fe2O3 nanoparticles, but also a H2 adsorption competitor that decreased H2/CO ratio over active sites to reduce the possibility of further hydrogenation of olefins. The KMnO4 modified iron catalysts exhibited high CO conversion and olefins selectivity (∼40%) due to the improved distribution of iron and the auxiliary functions of Mn. Residual potassium is also in favor of the formation of iron carbides to increase CO conversion.
      Graphical abstract image

      PubDate: 2017-05-12T16:26:40Z
      DOI: 10.1016/j.apcata.2017.05.001
      Issue No: Vol. 541 (2017)
       
  • Selective hydrogenolysis of αO4, βO4, 4O5 CO bonds of lignin-model
           compounds and lignin-containing stillage derived from cellulosic
           bioethanol processing
    • Authors: B. Gómez-Monedero; M.P. Ruiz; F. Bimbela; J. Faria
      Pages: 60 - 76
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): B. Gómez-Monedero, M.P. Ruiz, F. Bimbela, J. Faria
      Benzyl phenyl ether (BPE), phenethyl phenyl ether (PPE) and diphenyl ether (DPE) have been selected as model compounds of the most abundant and significant ether linkages found within the complex structure of lignin (e.g. αO4, βO4, and 4O5, respectively). The catalytic hydrogenolysis of these compounds has been carried out using several Ru, Pd and Ni catalysts supported over different metal oxides (e.g. Al2O3, ZrO2, TiO2) and carbon materials (e.g. active carbon, multiwall carbon nanotubes). The conversion of these compounds at relevant hydroprocessing conditions (150°C, 25bar-g in H2 atmosphere) is much dependent on the labile nature of the relevant ether bonds of the selected model compounds. Conversion levels for the three compounds increases in the following order: DPE (4O5 linkage)<PPE (βO4)<BPE (αO4). Product distribution is also dependent on the chemical structure of the raw material subjected to catalytic hydroprocessing, with BPE and DPE mainly yielding aromatic monomers, whilst fully saturated monomers are the main reaction products when PPE is hydroprocessed. The reaction mechanisms upon hydroprocessing vary from one model compound to another, being hydrogenolysis the prevailing route in the catalytic hydroprocessing of BPE and DPE, whereas competing reaction pathways between dimer hydrogenation and hydrogenolysis of the CO bond occur for the PPE molecule. The conversion and selectivity to relevant hydrogenolysis products are also dependent on the catalyst used. Ru-based catalysts are the most active followed by Pd −based and Ni-based, whereas selectivity to aromatic monomers increases in the reverse order (Ni>Pd>Ru). The catalytic systems with easier reducible species performes better in the conversion of the dimer models. Besides, a preliminary study on the catalytic depolymerization of a real lignin stream (lignin-containing 2G bioethanol plants stillage) has been carried out. Detailed characterization by 13C-1H heteronuclear single-quantum correlation spectroscopy (HSQC) showed that on 5wt.% Ru/C it is possible to achieve 50% desapearance of the most abundant lignin ether bond (i.e. βO4) and liquid yields above 50wt.%.
      Graphical abstract image

      PubDate: 2017-05-17T18:16:52Z
      DOI: 10.1016/j.apcata.2017.04.022
      Issue No: Vol. 541 (2017)
       
  • Effect of Cr2O3 loading on the properties and cracking activity of
           Pt/Cr2O3-ZrO2
    • Authors: N.H.R. Annuar; S. Triwahyono; A.A. Jalil; N. Basar; T.A.T. Abdullah; A. Ahmad
      Pages: 77 - 86
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): N.H.R. Annuar, S. Triwahyono, A.A. Jalil, N. Basar, T.A.T. Abdullah, A. Ahmad
      The effects of Cr2O3 loading ranging from 1 to 12wt.% on the properties, structure and isopropylbenzene (IPB), 1,4-diisopropylbenzene (DIPB) and 1,3,5-triisopropylbenzene (TIPB) hydrocracking activities of Pt/Cr2O3-ZrO2 (Pt/CrZr) were studied. The properties of Pt/CrZr were characterized with XRD, BET, IR and UV–vis spectrometer. The acidity was determined by 2,6-lutidine adsorbed IR spectroscopy. The introduction of Cr2O3 on ZrO2 intensified continuously the tetragonal phase of ZrO2 and bulk crystalline Cr2O3, while the surface area and acidity passed through a maximum of Cr2O3 loading at 8wt.%. The IR study confirmed the presence of CrO stretching bands at 1035 and 1013cm−1 on Pt/CrZr. No dioxo species involving the stretching modes of OCrO existed. H2 and 2,6-lutidine showed different interactions with Pt/CrZr in which the band at 1013cm−1 is more extensively affected with 2,6-lutidine adsorption for all Pt/CrZr and the band at 1035cm−1 is more affected with H2 adsorption for Cr2O3 loading at≤8wt.%. While, at >8wt.% Cr2O3 loading, the H2 is more interacted with the band at 1013cm−1. These results suggested that the absorbance bands at 1013 and 1035cm−1 are assignable to the stretching of the CrO which is connected to the other Cr through O and CrO which is connected to cus Zr4+ through O, respectively. The catalyst with 8wt.% loading performed with a maximum activity in IPB, DIPB and TIPB hydrocracking at 523K which may be due to presence of CrO band at 1035cm−1 which extensively interacted with H2 to form protonic acid sites via a hydrogen spillover phenomenon. In fact, Cr2O3 loading at 8wt.% possessed strong permanent Lewis acid sites which play an important role in the stabilization of an electron during the formation of protonic acid sites.
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      PubDate: 2017-05-17T18:16:52Z
      DOI: 10.1016/j.apcata.2017.05.006
      Issue No: Vol. 541 (2017)
       
  • A review on reaction mechanisms of metal-catalyzed deoxygenation process
           in bio-oil model compounds
    • Authors: Andrew Ng Kay Lup; Faisal Abnisa; Wan Mohd Ashri Wan Daud; Mohamed Kheireddine Aroua
      Pages: 87 - 106
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Andrew Ng Kay Lup, Faisal Abnisa, Wan Mohd Ashri Wan Daud, Mohamed Kheireddine Aroua
      Bio-oil is a potential liquid fuel source which can be produced through the pyrolysis of biomass. Catalytic deoxygenation is an instrumental step for the defunctionalization of bio-oil which will result in liquid fuel which is of lower oxygen content and higher heating value. Numerous studies were done to investigate the deoxygenation mechanisms and the kinetics of various bio-oil model compounds. In this review, heterogeneous metal-catalyzed deoxygenation mechanisms of oxygenated model compounds with functional groups such as phenolics, furans, ethers, carboxylic acids, aldehydes, ketones and alcohols were compared and discussed. The limitations, benefits and feasibilities of such mechanisms were also presented in this article. The discussions on the classes of model compounds and the bonding configurations of oxygenated compounds have also shown that there is a strong correlation between these parameters and the reaction pathways. Hence, this review presented a summary of the model compound based approach researches which would be useful in correlating such knowledge with the actual bio-oil deoxygenation process. Several outlooks on the deoxygenation reactivity of model compounds were also presented in this article based on the studies on the literatures.
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      PubDate: 2017-05-17T18:16:52Z
      DOI: 10.1016/j.apcata.2017.05.002
      Issue No: Vol. 541 (2017)
       
  • A scalable production of anisonitrile through organoselenium-catalyzed
           dehydration of anisaldoxime under solventless conditions
    • Authors: Xiaobi Jing; Tingting Wang; Yuanhua Ding; Lei Yu
      Pages: 107 - 111
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Xiaobi Jing, Tingting Wang, Yuanhua Ding, Lei Yu
      An organoselenium-catalyzed dehydration reaction of anisaldoxime to produce the useful fine chemical anisonitrile was achieved under solventless conditions without using any dehydrant. Simple PhSe(O)OH could be employed as the recyclable and reusable catalyst without obvious deactivation, and the reaction generated no wastes at all. By an easily operable distillation process, the product could be isolated in high purity, as confirmed by NMR spectroscopic analysis. The reaction was scalable to at least kilogram-scale with excellent carbon mass balance at 99.3%, showing very great potential of the method in industrial-scale production. The mechanism of the reaction was also discussed based on the experimental findings.
      Graphical abstract image

      PubDate: 2017-05-17T18:16:52Z
      DOI: 10.1016/j.apcata.2017.05.007
      Issue No: Vol. 541 (2017)
       
  • Organic ligands incorporated hypercrosslinked microporous organic nanotube
           frameworks for accelerating mass transfer in efficient heterogeneous
           catalysis
    • Authors: Yang Xu; Tianqi Wang; Zidong He; Minghong Zhou; Wei Yu; Buying Shi; Kun Huang
      Pages: 112 - 119
      Abstract: Publication date: 5 July 2017
      Source:Applied Catalysis A: General, Volume 541
      Author(s): Yang Xu, Tianqi Wang, Zidong He, Minghong Zhou, Wei Yu, Buying Shi, Kun Huang
      Microporous organic polymers (MOP) usually have dominated micropores smaller than 2nm, which may restrict their performance in the mass transfer processes. Adding mesopores into microporous materials to form hierarchical structure has been recognized as a promising route to eliminate their transport limitations and further improve their value in applications. Here we report a straightforward method for the synthesis of organic ligands incorporated hypercrosslinked microporous organic nanotube frameworks (O-HMONFs) via Friedel-Crafts hyper-crosslinking reaction of small aromatic organic ligands with core-shell bottlebrush copolymers as platforms for heterogeneous catalysts. In particular, because of the mesopores produced by the core degradation, O-HMONFs-based catalysts showed more comparable activities than the corresponding disordered MOP-based catalyst and homogeneous molecular catalyst under similar conditions. More importantly, this method might be suitable for various aromatic organic ligands and could be used as a general approach to produce a variety of functional microporous organic nanotube frameworks.
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      PubDate: 2017-05-17T18:16:52Z
      DOI: 10.1016/j.apcata.2017.05.005
      Issue No: Vol. 541 (2017)
       
  • Ni/HZSM-5 catalyst preparation by deposition-precipitation. Part 1. Effect
           of nickel loading and preparation conditions on catalyst properties
    • Authors: R.R. Barton; M. Carrier; C. Segura; J.L.G. Fierro; N. Escalona; S.W. Peretti
      Pages: 7 - 20
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): R.R. Barton, M. Carrier, C. Segura, J.L.G. Fierro, N. Escalona, S.W. Peretti
      Nickel metal supported on HZSM-5 (zeolite) is a promising catalyst for lignin depolymerization. In this work, Ni/HZSM-5 catalysts were synthesized via deposition-precipitation (DP) and characterized. The effect of synthesis parameters; including nickel loading, DP time (synthesis contact time), and calcination temperature, on catalyst properties were studied. N2 and CO2 adsorption techniques were used to look at textural properties and confirmed the existence of lamellar species generated from DP. X-ray diffraction (XRD) confirmed that nickel metal was present on the support after reduction and passivation of the catalyst. Temperature programmed reduction showed that all the catalyst preparations were reducible at 733K after 4h, and that the DP method formed a mixture of Ni2+ species on the support. Transmission electron microscopy, XRD, and H2 chemisorption were used to determine approximate particle size and dispersion of nickel metal. From all the preparations, the 15wt% Ni/HZSM-5 catalyst with long DP time (16h) and low calcination temperature (673K), exhibited the most favorable particle size (∼5nm) and dispersion (7%).
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      PubDate: 2017-05-02T03:30:39Z
      DOI: 10.1016/j.apcata.2017.03.040
      Issue No: Vol. 540 (2017)
       
  • Effect of lanthanum promoter on the catalytic performance of levulinic
           acid hydrogenation over Ru/carbon fiber catalyst
    • Authors: Wenjing Song; Zhou Chen; Weikun Lai; I. Rodríguez-Ramos; Xiaodong Yi; Weizheng Weng; Weiping Fang
      Pages: 21 - 30
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): Wenjing Song, Zhou Chen, Weikun Lai, I. Rodríguez-Ramos, Xiaodong Yi, Weizheng Weng, Weiping Fang
      A series of La-modified Ru/carbon fiber (CF) catalysts was designed, and used for the conversion of levulinic acid (LA) into γ-valerolactone (GVL) under batch reactor conditions. The dopant of Lanthanum improved the hydrogenation activity from 37.7μmolgcat −1 s−1 to 216.1μmolgcat −1 s−1 when the mole La/Ru was 0.5 on the catalyst. Even in low temperatures, the Ru1La0.5/CF catalyst also showed a high activity in the hydrogenation of LA. Aiming at a detailed understanding the role of Ru-La interactions in the catalyst, the Ru1Lax/CF catalysts was characterized by the H2-TPR, H2-TPD, CO2-TPD, XPS, TEM and CO chemsorption. The electron density of Ru species has been enhanced by La addition to Ru/CF. The hydrogenation activity was a consequence of the amount of Ru active site and the promoting effect of Ru-La interaction.
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      PubDate: 2017-05-02T03:30:39Z
      DOI: 10.1016/j.apcata.2017.04.004
      Issue No: Vol. 540 (2017)
       
  • Adsorption and dissociation of H2O and CO2 on the clean and O-pre-covered
           Ru(0001) surface
    • Authors: Peng Zhao; Yurong He; Shaoli Liu; Dong-Bo Cao; Xiaodong Wen; Hongwei Xiang; Yong-Wang Li; Haijun Jiao
      Pages: 31 - 36
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): Peng Zhao, Yurong He, Shaoli Liu, Dong-Bo Cao, Xiaodong Wen, Hongwei Xiang, Yong-Wang Li, Haijun Jiao
      Periodic density functional theory (revised PBE; RPBE) and ab initio atomistic thermodynamics were used to assess the dissociative adsorption of H2O and CO2 on a (5×5) Ru(0001) surface model. For H2O dissociation on clean Ru(0001) [H2O→OH+H→O+2H], the first step has lower barrier than the second step (0.75 vs. 0.80eV). On O pre-covered Ru(0001), H2O dissociation [H2O+O→2OH] has lower barrier (0.62eV) and is more exothermic (−0.29 vs. −0.15eV). CO2 dissociation on clean Ru(0001) [CO2 →CO+O] needs low barrier (0.23eV) and is highly exothermic by 1.47eV. In turn, CO2 formation from surface O removal by CO has barrier of 1.70eV, in agreement with the experimentally detected 1.80±0.15eV. That the computed CO desorption energy (1.55eV) is smaller than CO oxidation barrier is in agreement with the experimental finding. The computed desorption temperatures of H2O, CO and CO2 under ultrahigh vacuum conditions agree perfectly with the experiments. In addition, high oxygen and OH pre-coverage do not significantly affect the energetics of the dissociation of H2O and CO2. The excellent agreement between theory and experiment confirms the applied models and methods, and in turn, gives the reliability and confidence about the further predicted results.
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      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.016
      Issue No: Vol. 540 (2017)
       
  • Cu/ZnO/SiO2 catalyst synthesized by reduction of ZnO-modified copper
           phyllosilicate for dimethyl ether steam reforming
    • Authors: Xinlei Wang; Kui Ma; Lihong Guo; Ye Tian; Qingpeng Cheng; Xueqin Bai; Jingjing Huang; Tong Ding; Xingang Li
      Pages: 37 - 46
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): Xinlei Wang, Kui Ma, Lihong Guo, Ye Tian, Qingpeng Cheng, Xueqin Bai, Jingjing Huang, Tong Ding, Xingang Li
      Herein, we reduced the ZnO-modified copper phyllosilicate to synthesize a series of Cu/ZnO/SiO2 catalysts (xCuZn/SiO2) which were mixed with γ-Al2O3 for dimethyl ether steam reforming (DME SR). The structure and the formation of copper phyllosilicate were systematically characterized by nitrogen adsorption, XRD and IR. The novel synthetic route led to the remarkably high dispersion of copper species and adjustable Cu0/Cu+ ratio on the catalyst surface, resulting in the superior catalytic performance for DME SR. The amount of Cu0 and Cu+ sites on the catalyst surface was dramatically affected by ZnO loading, and the turnover frequency results indicated that the 4CuZn/SiO2 catalyst (Cu/Zn=4) with the Cu0/Cu+ ratio of 1 showed the highest catalytic performance. The XPS, H2-TPR and TEM results revealed the existence of strong interaction between Cu species and ZnO on the reduced 4CuZn/SiO2 catalyst, which suppressed the reverse water-gas reaction and prevented the sintering of copper.
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      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.013
      Issue No: Vol. 540 (2017)
       
  • Kinetics and dynamics of methanol steam reforming on CuO/ZnO/alumina
           catalyst
    • Authors: Rajesh Thattarathody; Moshe Sheintuch
      Pages: 47 - 56
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): Rajesh Thattarathody, Moshe Sheintuch
      The kinetic and dynamic behavior of the methanol steam reforming (MSR) over CuO/ZnO/Al2O3 catalyst were followed at various steam to carbon (S/C) ratio using temperature ramping and steady state input conditions. The data is required for designing a methanol reformer-internal combustion engine (ICE) system, utilizing the reforming products as fuel for ICE while using the hot exhaust gases to heat the reformer. The catalyst exhibited high activity above 200°C for MSR and above 250°C for methanol decomposition reactions, making methanol a good hydrogen vector. The production of undesired byproducts, methyl formate and dimethyl ether, declined with increasing S/C and vanish at S/C=1. Rate oscillations were observed during MSR on CuO/ZnO/Al2O3 under isothermal conditions and S/C ∼1 for the first time. Oscillations with a period of 10min in order of magnitude, were observed in all MS signals with some phase shift between them. A simple kinetic model was developed for methanol decomposition (MD) using S/C=0 data and the rate and activation energies were determined. Calculations using S/C=1 data assuming MD followed by WGS, show that at high temperatures the WGS is close to equilibrium.
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      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.012
      Issue No: Vol. 540 (2017)
       
  • Toluene catalytic combustion over copper modified Mn0.5Ce0.5 Ox solid
           solution sponge-like structures
    • Authors: Fangyun Hu; Jianjun Chen; Shen Zhao; Kezhi Li; Wenzhe Si; Hua Song; Junhua Li
      Pages: 57 - 67
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): Fangyun Hu, Jianjun Chen, Shen Zhao, Kezhi Li, Wenzhe Si, Hua Song, Junhua Li
      Catalytic combustion is a well-established way to remove the pollution of volatile organic compounds (VOCs), and the highly active catalyst is the key issue of this process. Herein, a series of sponge-like ternary mixed oxide were prepared by a facile surfactant modified coprecipitation approach. The structure properties were characterized via BET, XRD, Raman, TEM, EDS, H2-TPR, and XPS techniques. It was found that the Cu content significantly influences the catalytic activity in toluene combustion. The CMC-2 (Cu:Mn:Ce=1:5:5) showed the best catalytic performance under the air atmosphere, and the complete conversion of toluene was achieved at 240°C. The characterization reveals that a proper amount of Cu facilitates the incorporation of highly reducible Mn4+ into ceria lattice to form sponge-like MnCeOx solid solution structures. Such promotion effect of copper can improve the redox behavior, produce large amounts of Oα at the interface of CuOx/MnCeOx, both of which benefit the toluene combustion at low temperature. The findings of this work highlight the importance of Cu in preparation of the active MnOx−CeO2 catalyst for VOCs combustion.
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      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.010
      Issue No: Vol. 540 (2017)
       
  • Single-step synthesis of dimethyl ether from biomass-derived syngas over
           CuO-ZnO-MOx (M=Zr, Al, Cr, Ti)/HZSM-5 hybrid catalyst: Effects of MOx
    • Authors: Yuxi Hua; Xiaoming Guo; Dongsen Mao; Guanzhong Lu; Garry L. Rempel; Flora T.T. Ng
      Pages: 68 - 74
      Abstract: Publication date: 25 June 2017
      Source:Applied Catalysis A: General, Volume 540
      Author(s): Yuxi Hua, Xiaoming Guo, Dongsen Mao, Guanzhong Lu, Garry L. Rempel, Flora T.T. Ng
      A series of CuO-ZnO-MOx (M=Zr, Al, Cr, Ti) catalysts were prepared by co-precipitation method and characterized by ICP-OES, XRD, N2 adsorption, N2O titration, H2-TPR, and XPS. The CuO-ZnO-ZrO2 catalyst exhibits the highest BET surface area and Cu surface area. For all the CuO-ZnO-MOx catalysts, Cu0 was the predominant copper species detectable on the surface of both reduced and spent samples. As-prepared CuO-ZnO-MOx catalysts were mixed physically with HZSM-5 zeolite to synthesize dimethyl ether (DME) via biomass-derived syngas. The highest CO conversion and DME yield were obtained over a CuO-ZnO-ZrO2/HZSM-5 hybrid catalyst. The CO conversion increases with the increase in the Cu surface area, but the relationship between them is not linear. Due to the H2-deficient characteristic of biomass-derived syngas, the water-gas shift reaction, by which H2 can be produced in-situ for the hydrogenation of CO, plays an important role in the direct DME synthesis.
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      PubDate: 2017-05-08T07:54:19Z
      DOI: 10.1016/j.apcata.2017.04.015
      Issue No: Vol. 540 (2017)
       
  • Study of butanol conversion to butenes over H-ZSM-5: Effect of chemical
           structure on activity, selectivity and reaction pathways
    • Authors: Dieter Gunst; Konstantinos Alexopoulos; Kristof Van Der Borght; Mathew John; Vladimir Galvita; Marie-Françoise Reyniers; An Verberckmoes
      Pages: 1 - 12
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Dieter Gunst, Konstantinos Alexopoulos, Kristof Van Der Borght, Mathew John, Vladimir Galvita, Marie-Françoise Reyniers, An Verberckmoes
      To evaluate the viability of the use of butanol as a green chemical key molecule, the effects of temperature and site time on the transformation of the three butanol isomers, 1-butanol, 2-butanol and iso-butanol, towards butenes over H-ZSM-5 have been studied in search of the most promising isomer. Under dehydration conditions, 2-butanol is by far the most active and intermediate ether formation is only observed for 1-butanol. On the other hand, only isobutanol allows the direct formation of isobutene, the most valuable of the butene isomers. Hence, it is especially interesting to further stimulate the biomass derived isobutanol production, e.g. via genetic modification of appropriate microorganisms, in order to allow thereafter the formation of green drop-in isobutene upon dehydration with H-ZSM-5 in existing refineries. Due to the large potential of isobutanol, a reaction path analysis via ab-initio based microkinetic simulations is conducted for this molecule. Comparing these results with simulations on 1-butanol indicates that the shift is occurring due to a shift of the dominant reaction pathway towards the direct dehydration via anti elimination. A Gibbs free energy analysis shows that the large distortion of the transition state for isobutanol etherification renders this path far less favorable, resulting in the lack of formation of the di-alkyl ether, whilst the increased degree of substitution of the alkyl chain in isobutanol is found to promote the direct dehydration path, leading to an increase of the overall activity of isobutanol as compared to 1-butanol.
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      PubDate: 2017-04-11T02:09:53Z
      DOI: 10.1016/j.apcata.2017.03.036
      Issue No: Vol. 539 (2017)
       
  • Micellar effect on the direct Fischer synthesis of alkyl glucosides
    • Authors: J. Nowicki; J. Woch; M. Mościpan; E. Nowakowska-Bogdan
      Pages: 13 - 18
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): J. Nowicki, J. Woch, M. Mościpan, E. Nowakowska-Bogdan
      This manuscript presents results from the investigation on the synthesis of alkyl glucosides by the novel, very efficient and environmentally friendly protocol of the Fischer-type synthesis from unprotected glucose and aliphatic alcohols. The use of the dual functionality catalysts (surfactant+acid catalyst) and micellar reaction system are the main novelty of described method. It has been found, that in developed method of synthesis the reaction of unprotected glucose with aliphatic alcohols carried out with significantly different route, than the normal (classical) route and leads to alkyl glucopyranoside derivatives with high yields. In progress analyses by DLS, HPLC and GC/MS confirm the general postulated pathway of developed method.
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      PubDate: 2017-04-11T02:09:53Z
      DOI: 10.1016/j.apcata.2017.04.002
      Issue No: Vol. 539 (2017)
       
  • Selective hydrogenation of 3-Hexyn-1-ol with Pd nanoparticles synthesized
           via microemulsions
    • Authors: Thomas Montsch; Moritz Heuchel; Yvonne Traa; Elias Klemm; Cosima Stubenrauch
      Pages: 19 - 28
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Thomas Montsch, Moritz Heuchel, Yvonne Traa, Elias Klemm, Cosima Stubenrauch
      In the study at hand we present a design strategy for novel catalysts which can be used for the selective hydrogenation of alkynes to alkenes. The design of the novel catalysts is based on two main ideas, namely (1) the synthesis of Pd nanoparticles via microemulsions and (2) the use of highly-ordered mesoporous silica with a 3-D pore network (FDU-12) serving as support. The nanoparticles are deposited on FDU-12 in two different ways. Firstly, we simply impregnated the support with a dispersion of the nanoparticles. The resulting catalyst was not selective at all; on the contrary, it fully hydrogenated our model alkyne, namely 3-hexyn-1-ol. Secondly, we synthesized the FDU-12 in the presence of the nanoparticles (in-situ synthesis). In this case, we obtained one catalyst which performed as well as the Lindlar catalyst although the metal content was slightly lower and our catalyst contained no Pb. Another catalyst of the same series, prepared in the presence of another stabilizer, performed as well as the NanoSelect™ catalyst but at a 7 times higher metal content. For the sake of comparison we also impregnated FDU-12 via classical incipient wetness impregnation and again obtained a completely nonselective catalyst. Our results demonstrate that the in-situ synthesis has great potential as regards the development of novel catalysts.
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      PubDate: 2017-04-11T02:09:53Z
      DOI: 10.1016/j.apcata.2017.03.038
      Issue No: Vol. 539 (2017)
       
  • Deactivation study of the hydrodeoxygenation of p-methylguaiacol over
           silica supported rhodium and platinum catalysts
    • Authors: F.P. Bouxin; X. Zhang; I.N. Kings; A.F. Lee; M.J.H. Simmons; K. Wilson; S.D. Jackson
      Pages: 29 - 37
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): F.P. Bouxin, X. Zhang, I.N. Kings, A.F. Lee, M.J.H. Simmons, K. Wilson, S.D. Jackson
      Hydrodeoxygenation of para-methylguaiacol using silica supported Rh or Pt catalysts was investigated using a fixed-bed reactor at 300°C, under 4 barg hydrogen and a WHSV of 2.5h−1. The activity, selectivity and deactivation of the catalysts were examined in relation to time on stream. Three catalysts were tested: 2.5% Rh/silica supplied by Johnson Matthey (JM), 2.5% Rh/silica and 1.55% Pt/silica both prepared in-house. The Rh/silica (JM) showed the best stability with steady-state reached after 6h on stream and a constant activity over 3days of reaction. In contrast the other two catalysts did not reach steady state within the timeframe of the tests, with continuous deactivation over the time on stream. Nevertheless higher coking was observed on the Rh/silica (JM) catalyst, while all three catalysts showed evidence of sintering. The Pt catalyst (A) showed higher selectivity for the production of 4-methylcatechol while the Rh catalysts were more selective toward the cresols. In all cases, complete hydrodeoxygenation of the methylguaiacol to methylcyclohexane was not observed.
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      PubDate: 2017-04-11T02:09:53Z
      DOI: 10.1016/j.apcata.2017.03.039
      Issue No: Vol. 539 (2017)
       
  • Polyoxometalate based mesoporous acidic catalyst from biogenic silica for
           vegetable oil methanolysis: Structure activity relationship study
    • Authors: Raju Dutta; Sunit Kumar Singh; Sachin A. Mandavgane; Jayant D. Ekhe
      Pages: 38 - 47
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Raju Dutta, Sunit Kumar Singh, Sachin A. Mandavgane, Jayant D. Ekhe
      A superacidic mesoporous catalyst WOX/RHS-MCM-41 was synthesized using high purity biogenic silica extracted from an agro-waste, rice husk ash. Catalyst acidity was enhanced by dispersion of surface WOX groups on mesoporous support and was used for methanolysis of soybean oil and free fatty acid. Catalyst activity was found to depend upon the structure of WOX species formed over catalyst surface. Characterization with XRD, SEM, TEM, UV–vis DRS, Raman spectroscopy and acidity determination revealed that formation of highly dispersed amorphous polyoxotungstate phase on the catalyst surface developed with a specific tungsten loading and originated strong acidic sites showing high activity. Kinetic analysis revealed that pseudo-first order kinetics was followed up to the optimum reaction time with an activation energy 42.7kJmol−1. Catalyst showed high activity giving ∼90% FAME yield and reusability for multiple cycles without regeneration. The high catalytic activity was retained even in presence of free fatty acid also.
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      PubDate: 2017-04-11T02:09:53Z
      DOI: 10.1016/j.apcata.2017.03.032
      Issue No: Vol. 539 (2017)
       
  • δ-Alumina supported cobalt catalysts promoted by ruthenium for
           Fischer-Tropsch synthesis
    • Authors: Olga A. Kungurova; Alexander A. Khassin; Svetlana V. Cherepanova; Andrey A. Saraev; Vasily V. Kaichev; Natalya V. Shtertser; Galina K. Chermashentseva; Еvgeny Yu. Gerasimov; Еvgeny A. Paukshtis; Оlga V. Vodyankina; Tatyana P. Minyukova; Georges Abou-Jaoudé
      Pages: 48 - 58
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Olga A. Kungurova, Alexander A. Khassin, Svetlana V. Cherepanova, Andrey A. Saraev, Vasily V. Kaichev, Natalya V. Shtertser, Galina K. Chermashentseva, Еvgeny Yu. Gerasimov, Еvgeny A. Paukshtis, Оlga V. Vodyankina, Tatyana P. Minyukova, Georges Abou-Jaoudé
      The paper presents the low-temperature nitrogen adsorption, TG, XRD, IR spectroscopy, XPS, TEM and SEM data for ruthenium promoted (0.2–1wt.%) Сo-δAl2O3 catalysts and characteristics of the catalysts in Fischer-Tropsch synthesis after their activation under the conditions ensuring the reduction of comparable fractions of metallic cobalt. It was shown that cobalt in oxide precursors is a component of the spinel-like Со3-xAlxO4 phase containing the impurity anions СО3 2−, NO3 −, ОН−, and NO in promoted samples, which belong to the thermolysis product of the Ru precursor. Average sizes of Со3-xAlxO4 crystallites are in a range of 5–10nm. As ruthenium content in the catalyst increases upon reduction, the temperature of metallic phase formation decreases substantially (by more than 150°C). After the reduction, selectivity of promoted catalysts for α-olefins and high-molecular hydrocarbons was higher in comparison with unpromoted catalysts, without a noticeable decrease in catalytic activity. Therewith, in 0.5–1.0wt.% catalysts, a part of ruthenium forms individual ultradispersed metallic particles ca. 1nm in size that are located on the surface of oxide support and are not active in Fischer-Tropsch synthesis. The oxide layer decorating the surface of metallic cobalt particles is also strongly enriched with ruthenium. In the 0.2wt.% catalyst, the major part of ruthenium resides in metallic cobalt particles. Although the ruthenium-cobalt alloy segregates with enrichment of the surface with cobalt, the presence of ruthenium in the metallic particles and probably in the decorating oxide layer exerts a considerable effect on selectivity of the catalysts.
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      PubDate: 2017-04-18T14:02:15Z
      DOI: 10.1016/j.apcata.2017.04.003
      Issue No: Vol. 539 (2017)
       
  • Structure evolution of mesoporous silica supported copper catalyst for
           dimethyl oxalate hydrogenation
    • Authors: Yujun Zhao; Yaqing Zhang; Yue Wang; Jian Zhang; Yan Xu; Shengping Wang; Xinbin Ma
      Pages: 59 - 69
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Yujun Zhao, Yaqing Zhang, Yue Wang, Jian Zhang, Yan Xu, Shengping Wang, Xinbin Ma
      A modified ammonia evaporation method with an ordered mesoporous silica as the precursor of the support was applied to prepare the well dispersed copper-based catalysts. Appropriate amount of ammonia was used during the aging stage to prevent the destruction of the ordered mesoporous structure, which can ensure the homogeneous pre-distribution of the copper precursor ([Cu(NH3)4]2+) in the mesopores. Then the formation of copper phyllosilicate or surface Cu–O–Si species can be prompted during the ammonia evaporation stage, resulting in large surface areas of both Cu0 and Cu+ species in the final catalysts. It was also revealed that the formation of copper phyllosilicate led to the destruction of mesoporous silica structure in the ammonia evaporation stage especially at the higher copper loading. The catalysts with various copper loading were systematically characterized and applied in the hydrogenation of dimethyl oxalate to ethylene glycol (EG). An excellent low-temperature catalytic performance and stability were achieved on 20Cu/OMS with EG selectivity of 98.2% at 453K, due to the superior surface areas of both Cu0 and Cu+, as well as the highest ratio of Cu+/(Cu0 +Cu+).
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      PubDate: 2017-04-18T14:02:15Z
      DOI: 10.1016/j.apcata.2017.04.001
      Issue No: Vol. 539 (2017)
       
  • Efficient green catalysis for the conversion of fructose to levulinic acid
    • Authors: Indira Thapa; Brian Mullen; Ammar Saleem; Cora Leibig; R. Tom Baker; Javier B. Giorgi
      Pages: 70 - 79
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Indira Thapa, Brian Mullen, Ammar Saleem, Cora Leibig, R. Tom Baker, Javier B. Giorgi
      Highly efficient and selective production of levulinic acid has been achieved from D-fructose in the presence of polystyrene-based sulphonic acid resin catalyst, Dowex 50×8-100, at mild reaction conditions of 120°C, over 24h in a 50:50 mixture of water/GVL resulting in 72mol% yield under optimized reaction conditions. Optimization of the effect of reaction temperature, time, pressure, catalyst to substrate ratio, fructose concentration and solvent was performed. Various polystyrene-based sulfonic acid resins were also investigated for quantitative production of LA from 5-hydroxymethylfurfural (5-HMF) in pure water. Catalyst recycling was carried out up to 6 cycles. Significant mechanistic information was obtained for the formation of “humins”, which are the primary cause of catalyst fouling, by the identification of soluble by-products and polymerization presursors using Q-Tof mass spectrometry based on accurate masses.
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      PubDate: 2017-04-18T14:02:15Z
      DOI: 10.1016/j.apcata.2017.03.016
      Issue No: Vol. 539 (2017)
       
  • Sn and Zn modified HZSM-5 for one-step catalytic upgrading of glycerol to
           value-added aromatics: Synergistic combination of impregnated Sn
           particles, ALD introduced ZnO film and HZSM-5 zeolite
    • Authors: Fei Wang; Xuan Kang; Ma-xi Zhou; Xing-hui Yang; Li-jing Gao; Guo-min Xiao
      Pages: 80 - 89
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Fei Wang, Xuan Kang, Ma-xi Zhou, Xing-hui Yang, Li-jing Gao, Guo-min Xiao
      The chemoselective catalytic conversion of glycerol into high value-added aromatics (GTA) can greatly enhance the economic profits in biodiesel and biomass industry chain. In order to enhance the aromatization activity, stability and conversion efficiency of carbon in glycerol into aromatics during the GTA process, Zn species, which could directly convert alkenes originated from deoxygenation of glycerol into aromatics through dehydrogenation reaction, was introduced into Sn/HZSM-5 zeolite via atomic layer deposition (ALD) and incipient wet impregnation (IWI) method. Compared with impregnated ZnO modified Sn/HZSM-5, ZnO introduced by 20 ALD cycles into Sn/HZSM-5 deposited in the form of thin film, which not only fully coated both HZSM-5 external and internal surface, but also partially covered impregnated Sn particles. This film stabilized the oxidation state of loaded SnOx species which acted as catalytically active materials and further healed HZSM-5 structural defects, leading to the better synergistic effect among HZSM-5 zeolite, impregnated Sn particles and ALD introduced ZnO films. Besides, the reusability of this catalyst could be tremendously improved due to the protective effect of introduced ALD ZnO film which could prevent irreversible dealumination of HZSM-5 from exposure of HZSM-5 framework to steam during GTA reaction and regeneration procedure. However, when the deposited ZnO ALD cycle number reached 40, Sn particles on HZSM-5 could be completely packaged by ZnO film, on which occasion Sn could not participate in the GTA process, thereby leading to the reduction in both aromatics yields and catalyst lifetime.
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      PubDate: 2017-04-18T14:02:15Z
      DOI: 10.1016/j.apcata.2017.04.005
      Issue No: Vol. 539 (2017)
       
  • Synthesis of N,N-dimethylformamide from carbon dioxide in aqueous biphasic
           solvent systems
    • Authors: R. Kuhlmann; S. Schmitz; K. Haßmann; A. Prüllage; A. Behr
      Pages: 90 - 96
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): R. Kuhlmann, S. Schmitz, K. Haßmann, A. Prüllage, A. Behr
      This paper presents the homogeneous catalyzed hydrogenation of carbon dioxide to N,N-dimethylformamide (DMF) with an in-situ generated ruthenium catalyst based on RuCl3 ×H2O and the phosphine ligand 2,2′-bis(diphenylphosphinomethyl)-1,1′-biphenyl (BISBI). Investigations showed that the complex formation of an active species requires the presence of an amine. The catalyst was recycled by immobilization in a nonpolar alcoholic solvent while the formed product was extracted in-situ into the aqueous phase. The self-assembling reaction system showed stability for 10 recycling runs without a significant loss of activity resulting in an average yield of 31% DMF at 40bar and 140°C without the occurrence of any byproducts. Furthermore, a combination of the developed reaction system with ternary amines enables the application of wash amine solutions as carbon dioxide carrier.
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      PubDate: 2017-04-18T14:02:15Z
      DOI: 10.1016/j.apcata.2017.03.037
      Issue No: Vol. 539 (2017)
       
  • Liquid phase oxidation of cinnamyl alcohol to cinnamaldehyde using
           multiwall carbon nanotubes decorated with zinc-manganese oxide
           nanoparticles
    • Authors: Mohammad Sadiq; Khalid Saeed; Saima Sadiq; Sundas Munir; Mashooq Khan
      Pages: 97 - 103
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Mohammad Sadiq, Khalid Saeed, Saima Sadiq, Sundas Munir, Mashooq Khan
      Zinc-manganese (Zn-Mn) oxide nanoparticles were prepared and loaded on functionalized multiwall carbon nanotubes (FMWCNTs) (Zn-Mn oxide/FMWCNT) using co-precipitation and developing condensation methods, respectively. The Zn-Mn oxide and Zn-Mn oxide/FMWCNTs were characterized using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The catalytic efficiencies of the prepared catalysts were tested for liquid phase oxidation of cinnamyl alcohol (CnOH) to cinnamaldehyde (CnHO) in a modified batch reactor. The reaction parameters were optimized and compared in green (water and heptane), blue (toluene, acetonitrile, and cyclohexane), and red (benzene) solvents and molecular oxygen. The maximum CnOH-to-CnHO conversion of 97.2 and 99.9% with productivity of 63.2 and 65mmolg−1 h−1 was achieved with 0.1g of each Zn-Mn oxide and Zn-Mn oxide/FMWCNT, respectively in water at 60°C and time=120min. Both catalysts showed high conversion, high productivity, low cost, recyclability, and true heterogeneous behavior and therefore, can be used effectively for the conversion of CnOH-to-CnHO.
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      PubDate: 2017-05-02T03:30:39Z
      DOI: 10.1016/j.apcata.2017.04.007
      Issue No: Vol. 539 (2017)
       
  • Fabrication of an all solid Z-scheme photocatalyst g-C3N4/GO/AgBr with
           enhanced visible light photocatalytic activity
    • Authors: Xuli Miao; Xiaoping Shen; Jiajia Wu; Zhenyuan Ji; Jiheng Wang; Lirong Kong; Miaomiao Liu; Chunsen Song
      Pages: 104 - 113
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Xuli Miao, Xiaoping Shen, Jiajia Wu, Zhenyuan Ji, Jiheng Wang, Lirong Kong, Miaomiao Liu, Chunsen Song
      In this work, an excellent ternary visible-light all solid Z-scheme photocatalytic heterojunction of g-C3N4/GO/AgBr has been prepared by the attachment of graphene oxide (GO) to the surface of g-C3N4, followed by in-situ growth of AgBr nanoparticles on GO sheets. The g-C3N4/GO/AgBr heterojunction exhibits excellent photocatalytic efficiency for RhB degradation, which is about 17.5, 7.9, 3.5, 4.0 and 2.2 times as high as that of P25, g-C3N4, AgBr, g-C3N4/GO and g-C3N4/AgBr heterojunction, indicating the introduction of GO into the system largely improved the capability of the photocatalysis since GO acted as the charge transmission bridge between g-C3N4 and AgBr. Moreover, the photocatalytic performance of g-C3N4/GO/AgBr just showed a slight decrease after 4 degradation cycles, demonstrating a high stability of the g-C3N4/GO/AgBr photocatalyst. The photocatalytic mechanism investigation indicated that O2 − and h+ are the major active species in the photocatalytic process. It is expected that the GO-inserted Z-scheme photocatalytic heterojunction could be applied to practical pollutant degradation.
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      PubDate: 2017-05-02T03:30:39Z
      DOI: 10.1016/j.apcata.2017.04.009
      Issue No: Vol. 539 (2017)
       
  • Preparation of Ni-Mo2C/carbon catalysts and their stability in the HDS of
           dibenzothiophene
    • Authors: Haiyan Wang; Shida Liu; Rubenthran Govindarajan; Kevin J. Smith
      Pages: 114 - 127
      Abstract: Publication date: 5 June 2017
      Source:Applied Catalysis A: General, Volume 539
      Author(s): Haiyan Wang, Shida Liu, Rubenthran Govindarajan, Kevin J. Smith
      The HDS activity and stability of Ni-Mo2C/AC catalysts, prepared by carbothermal hydrogen reduction (CHR) at different temperatures and with different Ni:Mo ratios, is reported. The highest HDS activity occurred for catalysts with Ni:Mo ratios of 0.38 and 0.19, when prepared at the relatively low CHR temperature of 550 and 600°C, respectively. Partial sulfidation of the Ni-Mo2C/AC catalysts occurred rapidly upon reaction in 2wt% dibenzothiophene (DBT) at 350°C and 2.1MPa H2. Uptake of S was enhanced with increased Ni content, resulting in the formation of Mo2C-MoS2 core-shell structures. The stack height of the MoS2 shell increased with increased Ni content and promoted the direct desulfurization of DBT.
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      PubDate: 2017-05-02T03:30:39Z
      DOI: 10.1016/j.apcata.2017.04.008
      Issue No: Vol. 539 (2017)
       
  • Enhanced electrocatalytic hydrogen evolution performance of MoS2 ultrathin
           nanosheets via Sn doping
    • Authors: Cuicui Du; Hao Huang; Juan Jian; Yue Wu; Mengxiang Shang; Wenbo Song
      Pages: 1 - 8
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Cuicui Du, Hao Huang, Juan Jian, Yue Wu, Mengxiang Shang, Wenbo Song
      Two-dimensional (2D) transition-metal dichalcogenides (TMDs) have drawn much attention due to their unique physical and chemical properties. Molybdenum disulfide (MoS2) is particularly promising in hydrogen evolution reaction (HER) as a substitute for noble-metal catalysts. Although numerous attempts have been made to improve the HER activity of MoS2, engineering the MoS2-based electrocatalysts with activities similar to noble-metal catalysts remains challenging. Herein, we synthesize high-quality tin doped molybdenum disulfide (Sn-MoS2) ultrathin nanosheets by a g-C3N4 sacrificial template assisted thermolytic approach, and detailly investigate the role of Sn doping on the HER activity. The porous Sn-MoS2 nanosheets displays superior HER performance, exhibiting an overpotential of 28mV at 10mAcm−2 and a Tafel slope of 37.2mVdec−1 with an admirable stability. Compared to pristine MoS2 nanosheets, the significantly improved catalytic activity is ascribed to the increased active edge sites, enhanced intrinsic catalytic activity for each active site as well as accelerated electron transfer upon Sn doping. This work may provide guidelines for the design and synthesis of efficient non-precious HER catalysts.
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      PubDate: 2017-03-28T03:54:08Z
      DOI: 10.1016/j.apcata.2017.03.010
      Issue No: Vol. 538 (2017)
       
  • Amine-functionalized hyper-crosslinked polyphenanthrene as a metal-free
           catalyst for the synthesis of 2-amino-tetrahydro-4H-chromene and pyran
           derivatives
    • Authors: Reddi Mohan Naidu Kalla; Anuraj Varyambath; Mi Ri Kim; Il Kim
      Pages: 9 - 18
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Reddi Mohan Naidu Kalla, Anuraj Varyambath, Mi Ri Kim, Il Kim
      The hyper-crosslinked microporous polyphenanthrene spheres were fabricated simply by the polymerization of phenanthrene using bromomethyl methyl ether as a bridging agent in the absence of any templates. The organic spheres were subjected to amine-functionalizing on the periphery of them using unreacted bromomethyl groups. The amine-functionalized microporous polyphenthrene could be employed as a highly effective and stable solid basic catalyst for the syntheses of functionalized 2-amino-tetrahydro-4H-chromene and pyran derivatives. The significant features of these reactions are high product yields, environmental benignity, short reaction time, broad substrate scope, and non-requirement of toxic solvents. Furthermore, the catalyst can be reused up to four times without significant loss of activity.
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      PubDate: 2017-03-28T03:54:08Z
      DOI: 10.1016/j.apcata.2017.03.009
      Issue No: Vol. 538 (2017)
       
  • Heterogeneously catalyzed persulfate by CuMgFe layered double oxide for
           the degradation of phenol
    • Authors: Yun Chen; Jingchun Yan; Da Ouyang; Linbo Qian; Lu Han; Mengfang Chen
      Pages: 19 - 26
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Yun Chen, Jingchun Yan, Da Ouyang, Linbo Qian, Lu Han, Mengfang Chen
      CuMgFe layered double oxide (CuMgFe-LDO) was successfully obtained from CuMgFe layered double hydroxide (CuMgFe-LDH) and employed to degrade phenol in the heterogeneous catalysis of persulfate (PS). The effects of CuMgFe-LDO dosage, PS concentration, initial pH (pH0) and the presence of common inorganic anions on the removal of phenol were comprehensively evaluated in this study. It was revealed that CuMgFe-LDO performed excellently in activating PS to remove phenol with a great stability under a wide range of pH0 values ranging from 5.0 to 11.0. With 0.5g/L CuMgFe-LDO and 0.5mmol/L PS at pH0 6.4, 95.3% of 0.1mmol/L phenol was removed within 30min. Based on the results of electron paramagnetic resonance (EPR) and radical quenching experiments, it was inferred that free radicals bounded to the surface of CuMgFe-LDO was the dominant oxidant for the degradation of phenol. Furthermore, p-benzoquinone was considered to be the major intermediate in the oxidation process. Finally, the CuMgFe-LDO exhibited excellent stability after 3 times recycling with the concentration of the leached copper ion at 0.19mg/L, being lower than the drinking water standard of U.S Environmental Protection Agency (1.3mg/L). The findings of the work provided a new insight into the remediation of phenol polluted water within the system of CuMgFe-LDO/PS.
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      PubDate: 2017-03-28T03:54:08Z
      DOI: 10.1016/j.apcata.2017.03.020
      Issue No: Vol. 538 (2017)
       
  • Mechanistic insight into the facet-dependent selectivity of ethylene
           epoxidation on Ag nanocatalysts
    • Authors: Lin Zhu; Wei Zhang; Jiqin Zhu; Daojian Cheng
      Pages: 27 - 36
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Lin Zhu, Wei Zhang, Jiqin Zhu, Daojian Cheng
      Ethylene epoxidation reaction to selectively produce the ethylene oxide (EO) is a crucial heterogeneous catalytic chemical process in industry. However, the intrinsic catalytic selectivity depending on the facet of commonly used Ag catalysts is still far from understanding. In this work, we used the periodical density functional theory (DFT) calculations to gain an atomistic insight into the facet-dependent reaction selectivity of the ethylene epoxidation on Ag catalysts. We investigated the adsorption of atomic or molecular oxygen and oxametallacycle (OMC) intermediate, and further study the dissociation of molecular oxygen and the reaction mechanism of ethylene epoxidation on (111), (110), (100), and (211) surfaces of Ag catalysts. Our results indicate that the adsorption of the O atom is not facet-dependent under low oxygen coverage. Moreover, although the adsorption of molecular oxygen is facet-dependent, the dissociation of molecular oxygen would not have the essential influence on selectively producing EO in the ethylene epoxidation reaction. In addition, the catalytic selectivity of ethylene epoxidation reaction is facet-dependent, following the order of (110)>(100)>(111)>(211), which is consistent with the order of the adsorption strength of the OMC intermediate. Our results show that the stability of the OMC intermediate has an essential effect on the selectivity to EO in the ethylene epoxidation reaction. We have faith in that our results can provide useful information which would guide the intellectual design of the catalysts for ethylene epoxidation by controlling their morphologies.
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      PubDate: 2017-03-28T03:54:08Z
      DOI: 10.1016/j.apcata.2017.03.011
      Issue No: Vol. 538 (2017)
       
  • Highly dispersed CuyAlOx mixed oxides as superior low-temperature alkali
           metal and SO2 resistant NH3-SCR catalysts
    • Authors: Qinghua Yan; Yu Nie; Ruoyan Yang; Yuhan Cui; Dermot O’Hare; Qiang Wang
      Pages: 37 - 50
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Qinghua Yan, Yu Nie, Ruoyan Yang, Yuhan Cui, Dermot O’Hare, Qiang Wang
      For NO x removal from the exhaust gases of municipal solid waste (MSW) incinerators by selective catalytic reduction (SCR) technology, a suitable SCR catalyst which is active at low temperatures and robust to the presence of alkali metals and SO2 is highly desired. In this contribution, we report the successful fabrication of a highly dispersed CuyAlO x (y =2–4) mixed oxides for NH3-SCR catalyst using high surface area, flower-like highly dispersed AMO-Cu-Al-CO3 LDHs precursors. The influence of the Cu/Al ratio (2, 3, 4, and 5), calcination temperature (400, 500, 600, and 700°C), and testing temperature (150, 200, 250, and 300°C) on the activity of the CuyAlO x mixed oxide catalysts were systematically investigated. Among all samples, Cu4AlO x showed the highest NO x conversion of 91.1% at 200°C. After being thermally treated at 700°C, the NO x conversion of Cu4AlO x was still as high as 84.7%, which is much higher than that of the control catalyst 10wt% CuO/γ-Al2O3 (57.5%). XRD and HR-TEM analyses suggested that the highly dispersed CuO nanoparticles are the active species for the SCR reaction. The catalytic De-NO x performance of Cu4AlO x in the presence of alkali metals (K and Na) and SO2 was also studied. In the presence of 50ppm SO2, the NO x conversion of Cu4AlO x (78.4%) was much higher than that of CuO/γ-Al2O3 (48%). The selectivity of NO x conversion to N2 and resistance to H2O (and co-existence of H2O and SO2) for Cu4AlO x catalyst were also evaluated. In all, we have demonstrated that the newly obtained Cu4AlO x catalyst not only possesses higher thermal stability and higher low temperature (150–250°C) catalytic activity, but also has much better alkali metal (K and Na), SO2, and H2O resistance than a conventional CuO/γ-Al2O3 catalyst.
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      PubDate: 2017-03-28T03:54:08Z
      DOI: 10.1016/j.apcata.2017.03.021
      Issue No: Vol. 538 (2017)
       
  • β-Diimine nickel complexes in BMI·AlCl4 ionic liquid: a catalytic
           biphasic system for propylene oligomerization
    • Authors: Katiúscia Machado Nobre Borba; Michèle Oberson de Souza; Roberto Fernando de Souza; Katia Bernardo-Gusmão
      Pages: 51 - 58
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Katiúscia Machado Nobre Borba, Michèle Oberson de Souza, Roberto Fernando de Souza, Katia Bernardo-Gusmão
      β-Diimine nickel complexes have been synthesized using phenyl-amino-based ligands (NPh) substituted with none, two or three methyl groups. The resulting complexes, NiNPh, NiNPhMe2 and NiNPhMe3, which associated with ethylaluminum sesquichloride (EASC) as a co-catalyst, were tested for propylene oligomerization conducted under homogeneous and biphasic conditions using cyclohexane and the ionic liquid 1-methyl-3-butylimidazolium tetrachloroaluminate (BMI·AlCl4), respectively. The cocatalyst/nickel complex ratio was evaluated (Al/Ni=100 and 200) for both systems. Under homogeneous conditions, the highest activity was obtained with NiNPh and Al/Ni=100 (9s−1), and the highest selectivity in propylene dimers was attained with NiNPhMe3 (91%). Under biphasic conditions, all the catalysts showed activities similar or slightly superior to those obtained under homogeneous conditions; the highest activity was attained with NiNPh (10.8s−1), and the highest selectivity for propylene dimers was attained with NiNPhMe3 (98.3%). Under both reaction conditions, i.e., homogeneous and biphasic, 2-methyl-2-pentene was the major product. However, when reactions were conducted under biphasic conditions, less products were formed by isomerization in comparison with those formed using homogeneous systems. For the recycling reactions, no significant changes in the activity of the system were observed for each new cycle.
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      PubDate: 2017-03-28T03:54:08Z
      DOI: 10.1016/j.apcata.2017.03.014
      Issue No: Vol. 538 (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
      Pages: 59 - 65
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      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.
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      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.028
      Issue No: Vol. 538 (2017)
       
  • Layer effect on catalytic activity of Pd-Cu bimetal for CO oxidation
    • Authors: Ji Liu; Xiaofeng Fan; Chang Q. Sun; Weiguang Zhu
      Pages: 66 - 73
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Ji Liu, Xiaofeng Fan, Chang Q. Sun, Weiguang Zhu
      The bimetallic nanoparticles with core-shell structure have attracted much attention due to the excellent catalytic performance recently. We examined the thickness effect of the Pd overlayer/shell on Cu substrate/core on the catalytic ability of the overlayer using first-principle calculations and d-band center theory. It is found that overlayer thickness has the important effect on the d-band center of Pd layer. There is a quasi-linear relationship between the adsorption energies of O, O2, and CO and energy level of d-band center which is modulated by the overlayer thickness. The energy barriers of isolated O2 dissociation and CO oxidation are found to have an opposite trend with the shift of the d-band center. With this rule, the dissociation of O2 with the assistant of nearby CO is found to be easier on the surface of 2L-Pd/Cu(111).
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      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.019
      Issue No: Vol. 538 (2017)
       
  • Enhanced selective catalytic reduction of NO over Mn-Ce catalysts with the
           acetic-acid-chelated titania support at low temperature
    • Authors: Bo-Tau Liu; Chung-Jie Huang; Yu-Xuan Ke; Wei-Hong Wang; Han-Lin Kuo; Darren Lin; Vincent Lin; Sung-Hwa Lin
      Pages: 74 - 80
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Bo-Tau Liu, Chung-Jie Huang, Yu-Xuan Ke, Wei-Hong Wang, Han-Lin Kuo, Darren Lin, Vincent Lin, Sung-Hwa Lin
      In the study, we used the titania chelated with acetic acid (TAc) as the supports to prepare the highly active titania supported Mn-Ce catalysts for selective catalytic reduction of NO at low temperature. Characterization of the titania supported catalysts and the corresponding catalytic activity for NO removal were analyzed and evaluated. The TAc supported catalysts showed better Mn-Ce dispersion and catalytic activity for NO removal than the commercial TiO2 supported ones. Besides, the TAc supported catalysts also showed strong bonding at the TAc/TAc and the TAc/substrate interfaces, maintaining the integrity of the film after peeling test. We evaluated the catalytic activity for selective catalytic reduction of NO over the Mn-Ce catalysts wash-coated on ceramic monolith. Compared to the commercial TiO2 supported catalyst, the TAc supported one significantly enhanced the NO conversion by a factor of 1.25 and 1.58 times at 150 and 210°C, respectively. We speculate that the enhancement may arise from highly/uniformly-dispersed active centers on the surface of the TAc and the solidified structure of the coating layer. The well-dispersed active centers and the firm structure led to higher real space time when the NO stream flowed through the channels of the honeycombs, thereby resulting in a higher NO conversion.
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      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.029
      Issue No: Vol. 538 (2017)
       
  • Total oxidation of methane over supported CuO: Influence of the MgxAlyO
           support
    • Authors: Ionel Popescu; Nathalie Tanchoux; Didier Tichit; Ioan-Cezar Marcu
      Pages: 81 - 90
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Ionel Popescu, Nathalie Tanchoux, Didier Tichit, Ioan-Cezar Marcu
      Copper oxide supported on Al2O3, MgO and Mg(Al)O mixed oxides with Mg/Al atomic ratios of 1, 3 and 5 were prepared by coprecipitation followed by calcination at 750°C. These catalysts have been characterized by XRD, EDX, N2 adsorption, TG-DTG, NH3-TPD, CO2-TPD and H2-TPR, and their catalytic properties in the total oxidation of methane were investigated. Correlations between the physico-chemical properties and the catalytic activities were established. The best activity was obtained for the catalyst presenting a distribution of CuO species going from well distributed and aggregated CuO particles to CuAl2O4 phase on a Mg(Al)O support composed of a mixture of γ-alumina and periclase phases. It also possesses high relative amounts of strong acid and of medium and strong basic sites in this series. All the catalysts tested exhibited very good stabilities for the reaction conditions chosen and time-on-stream up to more than 50h.
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      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.012
      Issue No: Vol. 538 (2017)
       
  • 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
      Pages: 91 - 98
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      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.
      Graphical abstract image

      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.018
      Issue No: Vol. 538 (2017)
       
  • Mechanistic study of CO oxidation by N2O over Ag7Au6 cluster investigated
           by DFT methods
    • Authors: Yutthana Wongnongwa; Supawadee Namuangruk; Nawee Kungwan; Siriporn Jungsuttiwong
      Pages: 99 - 106
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Yutthana Wongnongwa, Supawadee Namuangruk, Nawee Kungwan, Siriporn Jungsuttiwong
      The potential of Ag7Au6 alloy nanocluster to be a catalyst for the oxidation of CO by N2O has been examined by density functional theory calculations. In the first mechanistic step, an N2O molecule decomposes at the Ag facet site of the Ag7Au6 cluster, yielding an N2 molecule and an Ag7Au6 O intermediate. In the second step, the Ag7Au6‐O intermediate readily reacts with CO to form CO2. The product CO2 desorbs easily from the active Ag7Au6 site, thus avoiding catalyst poisoning. The potential energy surfaces of the doublet- and quartet-states have been systematically elucidated. There is no spin crossing found for the entire reaction and the results show that the reaction preferably follows the doublet state pathway. The activation Gibbs free energy barrier for the first and second steps are 24.6 and 10.6 kcal/mol, respectively, while the Gibbs free energy of the overall reaction is −81.2 kcal/mol. The results reveal that this catalyzed reaction is both thermodynamically and kinetically favorable. Therefore, the Ag7Au6 nanocluster is predicted to be a promising and highly active catalyst for conversion of CO and N2O pollutants to non-harmful products under ambient conditions.
      Graphical abstract image

      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.025
      Issue No: Vol. 538 (2017)
       
  • 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 Naaresh Reddy; Santanab Giri; Priyabrat Dash
      Pages: 107 - 122
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Lipeeka Rout, Aniket Kumar, Rajendra S. Dhaka, G Naaresh 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–vis, 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 s−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.
      Graphical abstract image

      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.017
      Issue No: Vol. 538 (2017)
       
  • Pd3Cu coupling with nitrogen-doped mesoporous carbon to boost performance
           in glycerol oxidation
    • Authors: Wei Wang; Wangli Jing; Li Sheng; Dan Chai; Yumao Kang; Ziqiang Lei
      Pages: 123 - 130
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Wei Wang, Wangli Jing, Li Sheng, Dan Chai, Yumao Kang, Ziqiang Lei
      An electrocatalyst made by Pd3Cu alloy nanoparticles (NPs) supporting on nitrogen-doped mesoporous carbon (NMC), Pd3Cu/NMC, is applied to glycerol oxidation reaction (GOR). In this study, the nano-Al2O3 as a hard template, phenolic resin and melamine as nitrogen-containing carbon precursor afford a nitrogen-doped mesoporous carbon support that shows satisfactory effect in stabilizing Pd3Cu alloy NPs. Owing to the strong superimposed effect among nitrogen-doping, mesoporous structure and alloying action, the as-prepared Pd3Cu/NMC catalyst has high catalytic performance for GOR in alkaline medium. Notably, compared with Pd/C, the Pd3Cu/NMC exhibits higher oxidation peak current, better stability and lower activation energy. It is also found that glycerol electrooxidation on Pd3Cu/NMC catalyst is a diffusion controlled irreversible process. All results demonstrate Pd3Cu/NMC is an excellent electrocatalyst in GOR.
      Graphical abstract image

      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.027
      Issue No: Vol. 538 (2017)
       
  • Effect of hydrogen and propylene on the hydrogen peroxide decomposition
           over Pt, PtO and Au catalysts
    • Authors: E. Kertalli; J.C. Schouten; T.A. Nijhuis
      Pages: 131 - 138
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): E. Kertalli, J.C. Schouten, T.A. Nijhuis
      The decomposition of hydrogen peroxide (H2O2) on Pt, PtO and Au catalysts has been investigated in the presence of nitrogen, propylene and hydrogen. H2O2 formation on the catalyst is known to be a key intermediate step for the direct synthesis of propylene oxide (PO) from hydrogen, propylene and oxygen. Therefore, during this reaction, H2O2 is in contact with the catalyst on which it is produced, propylene and hydrogen. In this work we investigate the effect of the simultaneous presence of a metal catalyst (Pt, Au) and these gases on the H2O2 decomposition. The presence of hydrogen favors the decomposition of H2O2 over all the studied catalysts. This is attributed to the combination of direct decomposition and hydrogenation reactions. Furthermore, hydrogen changes the catalyst from an oxidized to a more metallic state accelerating the H2O2 decomposition. We also observed the positive effect of propylene on decreasing the decomposition activity of Pt and Au. The experimental results were used to estimate reaction rate constants. The obtained rate constants hinted to changes of the catalyst during the decomposition as the main reason for reaction rate changes. This was confirmed to happen for Pt but not for the Au catalyst. The decrease of H2O2 decomposition on Au in the presence of propylene is due to their interaction where propylene blocks the Au active sites responsible for the H2O2 decomposition.
      Graphical abstract image Highlights

      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.023
      Issue No: Vol. 538 (2017)
       
  • K- and Ca-promoted ferrosilicates for the gas-phase epoxidation of
           propylene with O2
    • Authors: Jaime García-Aguilar; Diego Cazorla-Amorós; Ángel Berenguer-Murcia
      Pages: 139 - 147
      Abstract: Publication date: 25 May 2017
      Source:Applied Catalysis A: General, Volume 538
      Author(s): Jaime García-Aguilar, Diego Cazorla-Amorós, Ángel Berenguer-Murcia
      In the propylene epoxidation reaction with Fe-SiO2 catalysts the presence of iron oxide particles has a detrimental effect due to the total combustion of propylene on these iron species. Thus, the complete elimination of the iron oxide particles is presented as a preliminary strategy in order to increase the selectivity towards propylene oxide in iron-based catalysts. In this sense, a simple post-treatment of the catalysts with alkali or alkaline-earth elements (such as K or Ca, respectively) has proven effective in the total elimination of these iron oxide particles. Furthermore, the addition of K and Ca has modified the physico-chemical properties of the catalysts, decreasing their superficial acidity and (for higher K or Ca loadings) masking/blocking the active sites responsible for the catalytic reaction. With all this, it is shown that K has a higher efficiency removing the iron oxide particles compared with Ca (for the same molar ratios) and that a higher amount of K (compared to Fe) is required for the complete elimination of the iron oxide particles. A considerable propylene oxide selectivity enhancement (up to 65%) has been obtained for the K-promoted Fe0.005SiO2 and Fe0.01SiO2 catalysts using O2 as sole oxidant.
      Graphical abstract image

      PubDate: 2017-04-04T03:14:28Z
      DOI: 10.1016/j.apcata.2017.03.031
      Issue No: Vol. 538 (2017)
       
 
 
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