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  Subjects -> ENGINEERING (Total: 2431 journals)
    - CHEMICAL ENGINEERING (210 journals)
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    - ENGINEERING (1271 journals)
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ENGINEERING (1271 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 8)
3D Research     Hybrid Journal   (Followers: 21)
AAPG Bulletin     Hybrid Journal   (Followers: 8)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 3)
ACS Nano     Full-text available via subscription   (Followers: 277)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 3)
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: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 7)
Advanced Journal of Graduate Research     Open Access  
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 5)
Advanced Science Letters     Full-text available via subscription   (Followers: 10)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
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Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 43)
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Advances in Remote Sensing     Open Access   (Followers: 44)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 3)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 6)
AIChE Journal     Hybrid Journal   (Followers: 35)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 26)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 10)
American Journal of Engineering Education     Open Access   (Followers: 10)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 24)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
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)
Antarctic Science     Hybrid Journal   (Followers: 1)
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: 18)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 11)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 5)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
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Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
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: 9)
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: 9)
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: 5)
Batteries     Open Access   (Followers: 6)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 28)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 1)
BER : Motor Trade Survey     Full-text available via subscription  
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 1)
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)
Beyond : Undergraduate Research Journal     Open Access  
Bhakti Persada : Jurnal Aplikasi IPTEKS     Open Access  
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Bilge International Journal of Science and Technology Research     Open Access  
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
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: 21)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 37)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal   (Followers: 1)
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 40)
Bitlis Eren University Journal of Science and Technology     Open Access  
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 13)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal   (Followers: 2)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 31)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 42)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Thermal Engineering     Open Access   (Followers: 5)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal  
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: 3)
CienciaUAT     Open Access   (Followers: 1)
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: 13)
City, Culture and Society     Hybrid Journal   (Followers: 22)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
Clinical Science     Full-text available via subscription   (Followers: 9)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 6)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 2)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 14)
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: 28)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Composite Structures     Hybrid Journal   (Followers: 282)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 210)
Composites Part B : Engineering     Hybrid Journal   (Followers: 247)
Composites Science and Technology     Hybrid Journal   (Followers: 196)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 16)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 20)
Computers & Geosciences     Hybrid Journal   (Followers: 31)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 8)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 5)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 7)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 34)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)

        1 2 3 4 5 6 7 | Last

Journal Cover
Applied Catalysis A: General
Journal Prestige (SJR): 1.237
Citation Impact (citeScore): 4
Number of Followers: 6  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0926-860X
Published by Elsevier Homepage  [3162 journals]
  • Enhancement of the 1-butanol productivity in the ethanol condensation
           catalyzed by noble metal nanoparticles supported on Mg-Al mixed oxide
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Jorge Quesada, Laura Faba, Eva Díaz, Salvador Ordóñez The role of the addition of a noble metal (Ru and Pd) on the surface of a basic mixed oxide (MgAl) used as ethanol condensation catalyst is studied in this work. The activity trends for all the reaction steps (dehydrogenation, condensation, dehydration, and hydrogenation) were analyzed, concluding that dehydrogenation step is the rate-determining one under inert conditions whereas hydrogenations also take a relevant role under reducing conditions. Ruthenium has shown very promising 1-butanol productivities at soft conditions (15 times higher than the parent material) whereas palladium performance is limited by the lateral decarbonylation reaction, and its high hydrogenation activity is only determining at temperatures higher than 650 K.Graphical abstractGraphical abstract for this article
       
  • Hydrodesulfurization of dibenzothiophene over NiW/(SnAlPO4-5+Al2O3)
           catalyst, the tuning effect of SnAlPO4-5 to the desulfurization reaction
           pathway
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Houxiang Sun, Qian Wang, Xinyue Zhang, Qianqian Yu, Lei Li, Yandan Wang, Baojian Shen SnAlPO4-5 molecular sieves were hydrothermally synthesized using SnCl2·2H2O as the tin source, and were verified that divalent tin was incorporated into the framework by isomorphous substitution of trivalent aluminum, and increasing the numbers of Brønsted and Lewis acid sites relative to those in AlPO4-5. The molecular sieves were used to fabricate hybrid supports with alumina and then were loaded with active metals to obtain NiW catalysts. The hydrodesulfurization (HDS) of dibenzothiophene (DBT) were evaluated for the catalytic activity of the catalysts. Because of the higher number of weak acid sites, much greater average number of slab layers and higher dispersion of WS2, the HDS rate of DBT at 280 °C is improved from 49.6% for the NiW/(AlPO4-5+Al2O3) catalyst to 82.2% for the NiW/(Sn0.12AlPO4-5+Al2O3) catalyst. Moreover, the highly active NiW/(Sn0.12AlPO4-5+Al2O3) catalyst obviously increases the product of the direct desulfurization route in the DBT HDS, which is beneficial for reducing hydrogen consumption in the industrial applications.Graphical abstractGraphical abstract for this article
       
  • Levulinic acid upgrade to succinic acid with hydrogen peroxide
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Davide Carnevali, Marco G. Rigamonti, Tommaso Tabanelli, Gregory S. Patience, Fabrizio Cavani Levulinic acid is produced from the acidic aqueous degradation of 5-hydroxymethylfurfural, with potential applications in bio-value added chemicals synthesis. Here, we report for the first time, the Baeyer-Villiger oxidation of levulinic acid to succinic acid, with hydrogen peroxide and tungstic acid at mild conditions and without any organic solvent. We investigated the effects of time, amount of reagent-to-catalyst molar ratio and H2O2-to-levulinic acid molar ratio. The maximum succinic acid selectivity was 75% with a levulinic acid conversion as high as 48%, after 6 h at 90 °C. We propose a reaction mechanism based on results obtained from the reactivity of the intermediates. The catalyst interacts with the substrate, forming a cyclic species that enhances the formation of succinic acid versus 3-hydroxypropanoic acid.Graphical abstractGraphical abstract for this article
       
  • Selective direct desulfurization way (DDS) with CoMoS supported over
           mesostructured titania for the deep hydrodesulfurization of
           4,6-dimethydibenzothiophene
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Issam Naboulsi, Benedicte Lebeau, Carlos F. Linares Aponte, Sylvette Brunet, Martine Mallet, Laure Michelin, Magali Bonne, Cedric Carteret, Jean-Luc Blin Mesostructured titania as support for the CoMoS active phase in deep HDS of 4,6-dimethydibenzothiophene leads to a modification of the main desulfurization way in contrast with the conventional CoMoS/alumina catalyst. Indeed, the dispersion of MoS2 active phase onto mesostructured titania supports leads to catalysts, which favor the direct desulfurization of 4,6-dimethydibenzothiophene. We demonstrate that this unexpected behavior is related to the intrinsic acid properties of the supports, arising from the coexistence of amorphous phase with semi-crystalline anatase. Indeed, these solids present both Lewis and Brönsted acidities, which are conserved after the impregnation of cobalt and molybdenum. The characteristic and the efficiency of the mesoporous titania catalysts have been compared either with conventional Al2O3, used for hydrotreatment, or P25, a commercial TiO2 support used as titania reference.Graphical abstractGraphical abstract for this article
       
  • Influence of silica sources on structural property and activity of
           Pd-supported on mesoporous MCM-41 synthesized with an aid of microwave
           heating for partial hydrogenation of soybean methyl esters
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Artita Na Rungsi, Apanee Luengnaruemitchai, Sujitra Wongkasemjit, Nuwong Chollacoop, Shih-Yuan Chen, Yuji Yoshimura MCM-41 has been hydrothermally synthesized using fumed silica (SiO2) and silatrane [Si(TEA)2] as silica sources. Pd nanoparticles were successfully impregnated to the mesoporous MCM-41 supports. Soybean oil methyl ester was partially hydrogenated by the Pd/MCM-41-SiO2 and Pd/MCM-41-silatrane catalysts under a mild condition (low temperature and pressure). Both catalysts could rapidly and selectively convert the polyunsaturated fatty acid methyl esters (C18:3 and C18:2) to monounsaturated fatty acid methyl esters (C18:1) at 100 °C and 0.4 MPa H2 within 4 h. The results verified that the Pd/MCM-41-silatrane catalyst with the greater surface of Pd active sites had higher catalytic activity, representing in term of turnover frequency (TOF), in partial hydrogenation than Pd/MCM-41-SiO2 under both C18:2 conversions of 40% and 60%. Even if the lower selectivity toward cis-C18:1 was obtained for the former. In addition to the better stable structure of MCM-41-silatrane support as compared to MCM-41-SiO2 support, silatrane precursor is more favorable to diminish the extent of complete hydrogenation than fumed silica as it provided the lower index. Even though, this silica precursor sues for more synthetic step. Due to the higher oxidative stability of Pd/MCM-41-SiO2, MCM-41-SiO2 support was further studied for the later research. When varying the Pd loadings in 0.5–2 wt.% on MCM-41-SiO2 support, the Pd(2)/MCM-41-SiO2 catalyst gave the highest performance (TOF) whether the complete hydrogenation was concurrently accompanied. Results signify that the nature of the silica source and the Pd concentration modified the surface active sites and size distribution of metallic particles, which determine the catalytic reactivity and selectivity.Graphical abstractGraphical abstract for this article
       
  • One-pot photoreforming of cellulosic biomass waste to hydrogen by merging
           photocatalysis with acid hydrolysis
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Jing Zou, Guan Zhang, Xiaoxiang Xu Environmental-friendly utilization and conversion of abundant lignocellulosic biomass waste into chemical fuels is considered as one of the efficient approaches developing renewable energy. Herein, we merge photocatalysis and acid hydrolysis to solve problems in biomass conversion and hydrogen production. Specifically, photocatalytic reforming cellulose to hydrogen has been accomplished by hydrolysis of cellulose in 0.6 M sulfuric acid solution at 403 K in the presence of a photocatalyst (e.g. platinized TiO2) under UV-light irradiation. Carbohydrates as the sacrificial electron donors are in situ generated via acid hydrolysis of cellulose. An unexpected production of 5-hydroxyl methyl furfural (HMF) has also been found during the combined process. In addition, efficient and repeatable hydrogen production has been achieved from photoreforming of raw biomass waste (paper pulp) as continuous supply of electron donors. Compared to traditional thermochemical gasification or pyrolysis of cellulose in high temperature and pressure, this work provides an alternative approach for producing hydrogen and valuable chemicals from lignocellulosic biomass.Graphical abstractEfficient photocatalytic reforming cellulosic biomass to hydrogen has been accomplished via merging photocatalysis and acid hydrolysis.Graphical abstract for this article
       
  • Highly oriented SnS2/RGO/Ag heterostructures for boosting
           photoeletrochemical and photocatalytic performances via schottky and RGO-n
           dual-heterojunctions interfacial effects
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Mingmei Zhang, Xinyong Li, Shiying Fan, Libin Zeng, Zhifan Yin, Tingting Lian, Guohua Chen A single semiconductor remains a great challenge for photocatalysis due to highly recombination of charge carriers. However, construction of multiple heterojunctions photocatalysts is an effective way for photocatalysis technique. Herein, two-dimensional sheet-like highly oriented SnS2/RGO/Ag (SRA) nanocomposites with multiple junctions including schottky- and RGO-n junctions designed and synthesized via hydrothermal strategy followed by in situ sequential UV reductions. The as-prepared SRA nanocomposites exhibited superior photoelectrochemical conversion efficiencies and photocatalytic activities for the degradation of typical antibiotics Norfloxacin (NOR) under simulated solar light condition, with the highest removal ratio of 94%. XPS and low temperature EPR technology demonstrates the existence of oxygen vacancies and chemical bond effect among SnS2, Ag and RGO components. Highly oriented crystal facet and efficient spatial charge carrier separations and interfacial transfers in the photo-induced redox reactions are evidenced by various physical techniques. Interestingly, in this paper, RGO was proposed to act as holes trapper to improve photo responsive charge separation in great extent. The mechanism of photoinduced redox reactions including the pathways of interfacial charges transfers and ROS species generations have been proposed in terms of the Density Functional Theory (DFT) quantum calculations and the outcomes of various physicochemical characterizations over SRA nanocomposites.Graphical abstractGraphical abstract for this article
       
  • Coupling Ru nanoparticles and sulfonic acid moieties on single MIL-101
           microcrystals for upgrading methyl levulinate into γ-valerolactone
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Zhenzhen Lin, Mengting Luo, Yindi Zhang, Xiaoxue Wu, Yanghe Fu, Fumin Zhang, Weidong Zhu Heterogeneous catalytic conversion of biomass-derived methyl levulinate (ML) to γ-valerolactone (GVL) is highly attractive as a sustainable route to mitigating the dependence on nonrenewable fossil resources. However, this route is limited by its low selectivity toward GVL and severe reaction conditions. Here, we present a synergistic catalytic process that offers exclusive GVL selectivity with complete ML conversion under mild conditions (80 °C, 0.5 MPa of H2 pressure). This is achieved over a dual-functionalized catalyst of Ru nanoparticles (Ru-NPs) and Brønsted acid SO3H groups in a Cr-based metal-organic framework (MIL-101). The Ru-NPs served as metal sites for the hydrogenation of ML to methyl-3-hydroxyvalerate (MHV) and the acidic SO3H moieties promoted the cyclization of MHV to generate GVL via lactonization. In contrast, GVL production was significantly suppressed over the physically mixed congener (2.0 wt% Ru/MIL-101 + MIL-101-SO3H). This result demonstrates an unrivalled advantage of the dual integration of metal/acid sites in a single MOF crystal, and the relative amount of sulfonic acid groups in the catalyst can exert significant influence on the overall catalytic performances. The activation energies for the hydrogenation and lactonization steps with the developed catalyst were 29.5 and 42.1 kJ/mol, respectively, which are much lower than those observed with the traditional 5.0 wt% Ru/AC catalyst.Graphical abstractGraphical abstract for this article
       
  • Focus on the catalytic performances of Cu-functionalized hydroxyapatites
           in NH3-SCR reaction
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): M. Schiavoni, S. Campisi, P. Carniti, A. Gervasini, T. Delplanche Hydroxyapatite loaded with different amounts of copper (from 2 to 11 wt.%, by using different Cu-precursors) was investigated as catalytic material for the NH3-SCR reaction. The method of copper addition affected the location and distribution of the copper phase in the hydroxyapatite samples as well as the aggregation state (isolated Cu2+ or CuxOy or CuO nano-aggregates). Ionic exchange procedure gave rise to Cu2+ stabilization in the exchange sites of HAP lattice, irrespective of the amount of Cu addition. Incipient wetness impregnation procedure provided samples with copper aggregation up to formation of CuO species at the highest Cu-loading. Sample characterization was performed by N2-adsorption/desorption, acidity measurement, EDX, TGA-DTGA, XRPD, UV–vis-DRS, and EPR to study the morphological and structural aspects of the copper phase.Catalytic tests of NH3-SCR revealed significant differences between the samples prepared by ionic exchange and impregnation, with activity that was dependent on the copper concentration on hydroxyapatite. Presence of 6 wt.% Cu was associated to the most active catalysts, in any case. Use of Cu-chloride and Cu-nitrate as precursors of Cu-phase, with the ionic exchange procedure, gave copper-hydroxyapatite catalysts with high activity/selectivity. Use of Cu-acetate as Cu-precursor caused some modification of the hydroxyapatite surface with enrichment of carbonate groups that were detrimental for the SCR activity.Graphical abstractGraphical abstract for this article
       
  • Borate-assisted liquid-phase selective oxidation of n-pentane
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Samson M. Aworinde, Kun Wang, Alexei A. Lapkin Oxidation of n-pentane with molecular oxygen to sec-pentanols was performed in the presence of a free radical initiator (di-tert-butyl peroxide) and a boron compound (sec-butyl metaborate), with in situ adsorption of water on molecular sieve 3 A. Kinetics of the reaction was studied in a laboratory-scale batch reactor over a broad range of conditions (130–150 °C, 20–30 bar, 5–10 vol% O2) in order to establish the optimum parameters for maximising the selectivity and yield of sec-pentanols. Results show that the initiator markedly improves the rate of oxidation, and hence yield, compared to thermal oxidation without an initiator, while the boron species enhances the selectivity to sec-pentanols. Under the conditions investigated, maximum sec-pentanol selectivity is 56% with an alcohol-to-ketone ratio of 3.6:1 for the borate-assisted oxidation compared to 33% and 1.1:1, respectively, for the oxidation without borate. This work demonstrates the feasibility of oxyfunctionalization of n-pentane with industrially relevant selectivity and yield.Graphical abstractGraphical abstract for this article
       
  • A study on structural features of bimetallic Pd-M/C (M: Zn, Ga, Ag)
           catalysts for liquid-phase selective hydrogenation of acetylene
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Daria V. Glyzdova, Aleksey A. Vedyagin, Anna M. Tsapina, Vasily V. Kaichev, Alexander L. Trigub, Mikhail V. Trenikhin, Dmitry A. Shlyapin, Pavel G. Tsyrulnikov, Alexander V. Lavrenov The present work is devoted to the study of doping effects of zinc, gallium and silver on the structure of active sites and catalytic properties of carbon-supported 0.5 wt% Pd catalysts in the liquid-phase selective hydrogenation of acetylene to ethylene. Carbonaceous graphite-like material Sibunit was used as a support. The reaction was performed in a medium of N-methyl-2-pyrrolidone at 55 °C. It was shown that the bimetallic Pd-Zn/C, Pd-Ga/C and Pd-Ag/C catalysts exhibit better activity and selectivity towards target product if compare with the monometallic Pd/C catalyst. The ethylene yield increases in a row as follows: Pd/C (19%) < Pd-Ag/C (34%) < Pd-Ga/C (42%) < Pd-Zn/C (53%). Using X-ray absorption spectroscopy and transmission electron microscopy it was found that an improvement of the selectivity is stipulated by the formation of bimetallic PdZn, PdxGay and PdAg nanophases. In the case of Pd-Zn/C and Pd-Ag/C systems, an increased distance between neighboring Pd atoms (2.82–2.89 Å) in relation with monometallic Pd/C, where this distance is 2.72 Å, was observed. The higher activity of modified bimetallic systems is connected with increased number of active sites due to enhanced dispersity of supported palladium doped with second metal.Graphical abstractGraphical abstract for this article
       
  • Rapid inkjet printing of high catalytic activity Co3O4/N-rGO layers for
           oxygen reduction reaction
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Victor Costa Bassetto, Jingjing Xiao, Emad Oveisi, Véronique Amstutz, Baohong Liu, Hubert H. Girault, Andreas Lesch The accurate and reproducible large-scale production of catalyst layers containing low-cost, abundant electrocatalysts gains in importance. Herein, pivotal factors are discussed that need to be considered when a combined inkjet printing and photonic curing platform is used as a promising fabrication method for catalyst layers based on a model low-cost catalyst, i.e., nitrogen-doped reduced graphene oxide supported cobalt oxide nano sheets (Co3O4/N-rGO), specifically prepared to formulate an inkjet ink. The ink is stable for weeks and can reproducibly be printed with piezoelectric printheads. Ink composition and printing parameters are optimized to achieve high-resolution printing and good adhesion on glassy carbon substrates. Polyvinylpyrrolidone and ethyl cellulose are used as catalyst stabilizers in the ink and must be removed through thermal post-processing to avoid a decrease of the electrical conductivity of the catalyst layer and a degradation of the catalytic activity of the Co3O4 nanocrystals. Conventional slow oven curing (i.e., hours) and photonic curing with a Xe flash lamp (seconds) are compared to generate temperatures above 400 °C under ambient conditions. Both techniques can increase the size of the Co3O4 nanocrystals from ∼7 nm up to ∼15 nm. Photonic curing with pulses above 2 J·cm–2 shot energy density initiates the reduction of the oxidation states of cobalt from (II,III) to (II). Residues and side products of polymeric stabilizers can be found using photonic curing pulses below 10 J·cm–2. This work highlights the advances made in digital printing and post-processing for catalyst layer production and demonstrates the importance of proper design of the ink, the printing and the post-processing for the large-scale production of catalyst layers for the ORR based on low-cost materials. The findings can be transferred to other metal and mixed metal oxide nanocatalysts.Graphical abstractGraphical abstract for this article
       
  • Partial oxidation of methane over monometallic and bimetallic Ni-, Rh-,
           Re-based catalysts: Effects of Re addition, co-fed reactants and catalyst
           support
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Chanittar Cheephat, Pornlada Daorattanachai, Sakamon Devahastin, Navadol Laosiripojana Partial oxidation reactions of CH4 over monometallic Ni, Rh, Re and bimetallic Re-Ni catalysts supported by Al2O3 were studied at 400–700 °C. Among monometallic catalysts, Rh/Al2O3 exhibited the highest catalytic activity. Lower CH4 conversion and H2 yield were observed over Ni/Al2O3 catalyst, while Re/Al2O3 catalyst did not promote the reaction under the studied condition. Addition of Re over Ni to form a bimetallic catalyst considerably promoted the activity of Ni/Al2O3 catalyst, particularly at a higher temperature (600 °C). Re-Ni proportion was then optimized; Re-Ni/Al2O3 at Re:Ni ratio of 3:7 resulted in a significantly higher CH4 conversion as well as H2 and CO yields when compared to noble-metal Rh/Al2O3 catalyst. Stability testing of Re-Ni/Al2O3, Ni/Al2O3 and Rh/Al2O3 catalysts was also conducted. After 18-h operation, Re-Ni/Al2O3 catalyst still exhibited high stability with slight deactivation in terms of H2 yield, whereas Ni/Al2O3 and Rh/Al2O3 catalysts showed higher deactivation rates. Post-reaction temperature programmed oxidation confirmed the better resistance toward carbon deposition of Re-Ni/Al2O3 catalyst. The effect of steam and CO2 addition on the Re-Ni/Al2O3 catalyst performance was also investigated. The presence of a suitable H2O content could increase H2 and CO yields and reduce the amount of carbon deposition, whereas the presence of CO2 showed undesirable influence on the reaction by reducing CH4 conversion and H2/CO ratio. Lastly, Re-Ni/Gd-CeO2 catalyst was prepared and tested to study the effect of catalyst support. The catalyst stability and resistance toward carbon deposition were significantly improved, which could be due to the high oxygen storage capacity of Gd-CeO2.Graphical abstractGraphical abstract for this article
       
  • Copper octacarboxyphthalocyanine as sensitizer of graphitic carbon nitride
           for efficient dye degradation under visible light irradiation
    • Abstract: Publication date: 5 August 2018Source: Applied Catalysis A: General, Volume 563Author(s): Seydou Ouedraogo, Bilel Chouchene, Christophe Desmarets, Thomas Gries, Lavinia Balan, René Fournet, Ghouti Medjahdi, Karifa Bayo, Raphaël Schneider In this paper, copper octacarboxyphthalocyanine (CuPc) was demonstrated to be an efficient photosensitizer of graphitic carbon nitride (g-CN) for the degradation of dyes like Orange II or Methylene Blue under visible light irradiation. UV–vis absorption, photoluminescence and photocurrent measurements demonstrate that CuPc not only allows to extend the absorption to wavelengths up to 1000 nm but also enhances the charge-transfer efficiency. The high photocatalytic efficiency of CuPc/g-CN nanohybrids originates from the strong association between the carboxylic acid groups of CuPc with g-CN which favor the transfer of photo-excited electrons from CuPc to g-CN. The CuPc/g-CN catalyst is stable, can be reused up to five times without significant loss of activity and is therefore of high potential for photocatalytic applications like wastewater treatment or hydrogen production under visible or near-infrared irradiation.Graphical abstractGraphical abstract for this article
       
  • Graphical abstract TOC
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s):
       
  • Graphical abstract TOC
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s):
       
  • Corrigendum to “Electrocatalytic removal of humic acid using
           cobalt-modified particle electrodes” [Appl. Catal. A, Gen. 559 (2018)
           75–84]
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Wenwen Zhang, Di Xie, Xue Li, Wenjian Ye, Xiaoxue Jiang, Yuanyuan Wang, Wenyan Liang
       
  • An ordinary nickel catalyst becomes completely selective for partial
           hydrogenation of 1,3-butadiene when coated with
           tributyl(methyl)phosphonium methyl sulfate
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Ahsan Jalal, Alper Uzun Performance of an ordinary supported nickel catalyst was tuned to reach an almost complete selectivity for partial hydrogenation of 1,3-butadiene by coating it with a phosphonium-type ionic liquid (IL), tributyl(methyl)phosphonium methyl sulfate, [P4441][MeSO4]. Thanks to high chemical and thermal stability of [P4441][MeSO4], the reaction conditions could be pre-optimized for high partial hydrogenation performance before the deposition of the IL coating. When the catalyst was coated with IL, it provided a total butene selectivity of 99.5 ± 0.2%, a record high partial hydrogenation selectivity ever reported for a nickel-based catalyst. X-ray photoelectron spectroscopy results illustrated that the IL donates electrons to nickel sites and makes them selective for partial hydrogenation. The conductor like screening model for realistic solvents (COSMO-RS) calculations indicated that the IL coating also exerts a filter effect, which helps to maintain this high partial hydrogenation selectivity at all conversion levels.Graphical abstractGraphical abstract for this article
       
  • Design and synthesis of Pt/ZSM-22 catalysts for selective formation of
           iso-Dodecane with branched chain at more central positions from n-Dodecane
           hydroisomerization
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Pengyu Niu, Ping Liu, Hongjuan Xi, Jun Ren, Minggui Lin, Qiang Wang, Xiaoyan Chen, Litao Jia, Bo Hou, Debao Li The formation of centrally branched iso-dodecane was controlled by absorption modes of alkene intermediates on ZSM-22, which included pore mouth type and key lock type. In this paper, we have designed and synthesized two kinds of ZSM-22 catalysts for selective formation of iso-dodecane with branched chain at more central positions from n-dodecane hydroisomerization. Aluminosilicate ZSM-22 was modified via carbonization of template to block the micropores and borosilicate ZSM-22 was synthesized. The characterization results and performance evaluation validated that micropore blockage could limit the pore mouth type at low reaction temperatures which favored the formation of iso-dodecane with side chain near the end of the carbon chain. Owing to the weak acid strength, higher temperatures, which favored the key lock mode, were needed to run the n-dodecane hydroisomerization over Pt/borosilicate ZSM-22. Both the two strategies for catalyst design achieved key lock adsorption mode and improvement of the selectivity for centrally branched iso-dodecane. Most importantly, weak acid sites on borosilicate ZSM-22 could catalyze double-bond isomerization reactions, which enhanced centrally branched iso-dodecane distribution up to more than 47%. Our research provides a prospective strategy for selective formation of centrally branched iso-alkanes and Pt/borosilicate ZSM-22 is expected to have potential applications in n-alkane hydroisomerization.Graphical abstractGraphical abstract for this article
       
  • Ni/HZSM-5 catalyst preparation by deposition-precipitation. Part 2.
           Catalytic hydrodeoxygenation reactions of lignin model compounds in
           organic and aqueous systems
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): R.R. Barton, M. Carrier, C. Segura, J.L.G. Fierro, S. Park, H.H. Lamb, N. Escalona, S.W. Peretti Nickel metal supported on HZSM-5 (zeolite) is a promising catalyst for lignin depolymerization. In this work, the ability of catalysts prepared via deposition-precipitation (DP) to perform hydrodeoxygenation (HDO) on two lignin model compounds in organic and aqueous solvents was evaluated; guaiacol in dodecane and 2-phenoxy-1-phenylethanol (PPE) in aqueous solutions. All Ni/HZSM-5 catalysts were capable of guaiacol HDO into cyclohexane at 523 K. The role of the HZSM-5 acid sites was confirmed by comparison with Ni/SiO2 (inert support) which exhibited incomplete deoxygenation of guaiacol due to the inability to perform the cyclohexanol dehydration step. The catalyst prepared with 15 wt% Ni, a DP time of 16 h, and a calcination temperature of 673 K (Ni(15)/HZSM-5 DP16_Cal673), performed the guaiacol conversion with the greatest selectivity towards HDO products, with an intrinsic rate ratio (HDO rate to conversion rate) of 0.31, and 90% selectivity to cyclohexane. Catalytic activity and selectivity of Ni/HZSM-5 (15 wt%) in aqueous environments (water and 0.1 M NaOH solution) was confirmed using PPE reactions at 523 K. After 30 min reaction time in water, Ni/HZSM-5 exhibited ∼100% conversion of PPE, and good yield of the desired products; ethylbenzene and phenol (∼35% and 23% of initial carbon, respectively). Ni/HZSM-5 in NaOH solution resulted in significantly higher ring saturation compared to the Ni/HZSM-5 in water or the NaOH solution control.Graphical abstractGraphical abstract for this article
       
  • Preparation, characterization, and catalytic performance of PdPt/3DOM
           LaMnAl11O19 for the combustion of methane
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Peng Xu, Xing Zhang, Xingtian Zhao, Jun Yang, Zhiquan Hou, Lu Bai, Huaiqiu Chang, Yuxi Liu, Jiguang Deng, Guangsheng Guo, Hongxing Dai, Chak-Tong Au Three-dimensionally ordered macroporus LaMnAl11O19 (3DOM LMAO) and its supported Pd, Pd–Pt, and Pt nanoparticles were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. The 1100 °C-calcined 3DOM LMAO support possessed a hexaaluminate phase, and its supported noble metal samples displayed a high surface area of 26–29 m2/g. A Pd–Pt alloy was generated in the PdPt/3DOM LMAO samples, and the particle sizes of the noble metal nanoparticles (NPs) were 3–5 nm. The 0.97 wt% Pd/3DOM LMAO (0.97 P d/3DOM LMAO) sample possessed the highest surface adsorbed oxygen concentration and the best low-temperature reducibility, showing the highest catalytic activity (T10% = 259 °C, T50% = 308 °C, and T90% = 343 °C at SV = 20,000 mL/(g h)) for methane combustion. The 1.14 wt% Pd2.8Pt/3DOM LMAO (1.14Pd2.8Pt/3DOM LMAO) sample performed the best (T10% = 284 °C, T50% = 372 °C, and T90% = 456 °C at SV = 20,000 mL/(g h)) among the PdPt/3DOM LMAO samples. Doping of Pt to the Pd-based catalyst could improve the H2O-, CO2-, and SO2-resistant ability without significant influence on thermal stability, although 1.14Pd2.8Pt/3DOM LMAO was less active than 0.97 P d/3DOM LMAO for methane combustion. The ex situ X-ray photoelectron spectroscopy was used to explore the formation of active PdO species during the oxidation processes of Pd in 1.14Pd2.8Pt/3DOM LMAO and 0.97Pd/3DOM LaMnAl11O19 at different temperatures.Graphical abstractGraphical abstract for this article
       
  • Structural stabilization and characterization of active peroxo species on
           TiO2-nanotube based materials in mild catalytic wet peroxide oxidation
           process
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Nina Drašinac Pajić, Petar Djinović, Goran Dražić, Jože Grdadolnik, Primož Šket, Janez Cerkovnik, Albin Pintar Amorphous TiO2 based nanotubes (TN) obtained through alkaline hydrothermal restructuring of P25 were treated with various acids and functionalized with hydrogen peroxide in order to tailor formation of structurally distinctive titanium peroxo species. Obtained solids were used as catalysts in the catalytic wet peroxide oxidation (CWPO) of model methyl orange (MO) aqueous solution under mild conditions. With the usage of 2 g/L of peroxide modified TN/ClO4p 0.01 catalyst and double stoichiometric amount of hydrogen peroxide, 50 ppm MO solution was purified up to 93% during 1 h at 40°C. No decay of catalyst activity was observed in 5 consecutive runs using the same catalyst batch. 17O NMR and TPD/MS analyses have revealed that catalytic activity of TN/ClO4p 0.01 sample can mainly be assigned to bidentate η2 surface peroxo species whose amount during 5 consecutive catalytic runs is almost constant, namely 5.9×10−7 and 5.2×10−7 mol/m2 prior and after usage, respectively. In addition, it has been observed that considerable amount of thermally labile oxygen species is used during 5 consecutive runs. From 17O NMR analysis we have observed that these species can be attributed to two coordinated (OTi2) oxygen formed on the place of terminal intra/interlayered −OH groups. Former can serve as structural stabilizing agents which enable formation of new η2 surface peroxo species during CWPO runs. To the best of our knowledge, this study is the first attempt to explain the possibility for η2 peroxo species structural stabilization during CWPO under mild conditions.Graphical abstractGraphical abstract for this article
       
  • Synthesis of glycerol carbonate from glycerol and dimethyl carbonate over
           DABCO embedded porous organic polymer as a bifunctional and robust
           catalyst
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Yali Wan, Yizhu Lei, Guosong Lan, Dingfu Liu, Guangxing Li, Rongxian Bai A large surplus of glycerol from the rapidly growing biodiesel industry has led to the conversion of glycerol into higher value-added products being of great industrial importance. In this paper, a promising route for the synthesis of glycerol carbonate from glycerol and dimethyl carbonate is described using DABCO (1,4-diazabicyclo[2.2.2]octane) embedded porous organic polymer as an efficient and robust catalyst. The porous catalyst with base sites and hydrophilic units (monoquaternized DABCO) was facilely synthesized through a one-pot radical copolymerization of divinylbenzene and vinyl functionalized DABCO monomer. By simply varying the mass ratio between divinylbenzene/DABCO monomer, the surface area, pore volume and surface wettability of the catalyst can be easily adjusted. Results of activity evaluations indicated that the catalyst with high surface area and excellent amphiphilicity exhibits much higher activity than other samples due to the enhanced accessibility of catalytic sites and mass transfer efficiency. Under the optimum reaction conditions, a 0.75 mol% catalyst loading is sufficient for excellent yield of glycerol carbonate in 60 min. Moreover, the optimized catalyst also shows excellent reusability and could be reused up to 13 consecutive recycles without obvious deactivation in activity.Graphical abstractGraphical abstract for this article
       
  • Mesoporous Al-promoted sulfated zirconia as an efficient heterogeneous
           catalyst to synthesize isosorbide from sorbitol
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Yi Zhang, Tong Chen, Gang Zhang, Gongying Wang, Hua Zhang Mesoporous aluminum-promoted sulfated zirconia (named as mAl-SZ) was directly prepared by grind method, and firstly used to catalyze the solvent-free dehydration of sorbitol to isosorbide. The physicochemical properties of as-prepared catalysts were characterized by FT-IR, TGA, XRD, N2 sorption, NH3-TPD and pyridine-infrared (IR) spectroscopy techniques in order to elucidate the relevance of the catalyst properties and the catalytic performance. It was found that the catalysts prepared by grind method possessed mesoporous structures with high surface area, pure tetragonal phase as well as high sulfur contents, which were advantage to eliminate diffusion limitation and generate abundant acidic sites, especially Brönsted acidic sites. Furthermore, aluminum promoters could contribute to the considerable increase of the strong acidic sites and ratio of Brönsted to Lewis acidic sites. Consequently, the mesoporous sulfated zirconia with 6 mol% Al-promoter (6Al-SZ) attained porous structure with improved acidic properties, thus showing the optimal catalytic behavior. The full sorbitol conversion with 73% isosorbide selectivity was achieved under milder conditions (175 °C, 2 h) than those of similar type of catalysts. In addition, the 6Al-SZ exhibited favorable reusability with insignificant drop in isosorbide yield during five reaction cycles.Graphical abstractGraphical abstract for this article
       
  • Pd core-shell alloy catalysts for high-temperature polymer electrolyte
           membrane fuel cells: Effect of the core composition on the activity
           towards oxygen reduction reactions
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Dae Jong You, Do Hyung Kim, Jeffrey Roshan De Lile, Chengbin Li, Seung Geol Lee, Ji Man Kim, Chanho Pak Pd-based core-shell alloy-supported catalysts were prepared sequentially via a microwave-assisted polyol method and galvanic replacement. To investigate the effect of the core composition on the catalytic activity of such catalysts, three different Pd alloy cores (PdNi, PdCu, and PdNiCu) were prepared on carbon supports using a polyol method. Then, Pd and Ir were introduced simultaneously to form shells on the Pd alloy cores by galvanic replacement in aqueous solution, thereby producing catalysts designated as PdNi@PdIr/C, PdCu@PdIr/C, and PdNiCu@PdIr/C. X-ray diffraction revealed that all three catalysts exhibited the face-centered cubic structure of Pd without the presence of individual phases for Ni, Cu, and Ir. The core-shell structure of the Pd-based alloy nanoparticles on the carbon support was verified by the electron energy loss spectroscopy line profile of a 25 nm nanoparticle of PdNiCu@PdIr/C. Among the three Pd-based core-shell catalysts, the highest electrochemical surface area and oxygen reduction reaction (ORR) activity was observed for PdNiCu@PdIr/C. In addition, the membrane electrode assembly employing the PdNiCu@PdIr/C catalyst displayed a significantly improved voltage compared to the other two catalysts under high-temperature polymer electrolyte membrane fuel cell conditions at 150 °C. Single-cell durability tests conducted to measure the voltage change at a constant current density of 0.2 A cm−2 showed a decay ratio of 12.3 μV h−1. These results suggest that the composition of the core in core-shell nanoparticles has an important influence on both the electronic properties in the Pd alloy core and compressive lattice strain on the PdIr shell. Control of these synergistic effects provides a new approach for developing catalysts with high ORR activity.Graphical abstractGraphical abstract for this article
       
  • Effects of a combination of lipases immobilised on desilicated and
           thiol-modified ZSM-5 for the synthesis of ethyl esters from macauba pulp
           oil in a solvent-free system
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Carina Akemi Araki, Sílvio Miguel Parmegiani Marcucci, Lidiane Sabino da Silva, Celso Hissao Maeda, Pedro Augusto Arroyo, Gisella Maria Zanin Lipases from Thermomyces lanuginosus (TLL) and Burkholderia cepacia (BCL) were immobilised on desilicated and thiol-modified ZSM-5 via covalent binding. These biocatalysts were tested, both alone and combined, in a reaction for the production of fatty acid ethyl esters from macauba pulp oil. A higher yield of esters was obtained with TLL combined with BCL, and the synergic effect was investigated systematically. Under the best conditions for the reaction, using a mixture of lipases (1% water content, 3:1 M ratio of ethanol to oil, at 30°C), the yield of ethyl esters was 93.1% ± 1.4% over48 h. The mixed lipases could be used in six operation cycles with a retained relative activity of higher than 60%. The combined biocatalysts were also evaluated using reactions carried out with macauba pulp oils with lower free fatty acid content, resulting in lower yields than those obtained with the initial oil.Graphical abstractGraphical abstract for this article
       
  • Monolithic Ni5Ga3/SiO2/Al2O3/Al-fiber catalyst for CO2 hydrogenation to
           methanol at ambient pressure
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Pengjing Chen, Guofeng Zhao, Ye Liu, Yong Lu A series of Ni5Ga3/m-SiO2/Al2O3/Al-fiber (m = 0, 0.5, 1.0, 3.0 and 5.0 wt%) catalysts have been developed for CO2 hydrogenation to methanol at ambient pressure. Microfibrous-structured SiO2/Al2O3/Al-fiber supports are obtained though endogenous growth of free-standing boehmite (AlOOH) nanosheets onto a three-dimensional (3D) network of 60 μm-Al-fiber thin felt with the aid of steam-only hydrothermal oxidation reaction between Al metal and H2O (2 Al + 4H2O → 2 AlOOH + 3H2), followed by calcination and SiO2-modification using silica sol. The bimetallic Ni5Ga3 nanoparticles are then placed onto the pore surface of as-obtained SiO2/Al2O3/Al-fiber support by co-impregnation method using Ni and Ga nitrates as precursors followed by reduction in H2 at 630 °C. The promising Ni5Ga3/1-SiO2/Al2O3/Al-fiber catalyst is capable of converting 2.3% CO2 into CH3OH with a high selectivity of 86.7% as well as 10.3%/3.0% selectivities to CO/CH4 at 210 °C, for a feed of CO2/H2/N2 (2/6/1, molar ratio). Such microfibrous-structured catalyst design combines the promising catalytic performance of Ni5Ga3 with the enhanced heat transfer and high permeability of the Al2O3/Al-fiber support. The effect of SiO2 loading on the formation of Ni5Ga3 alloy nanoparticles is also discussed.Graphical abstractGraphical abstract for this article
       
  • Adjustment of active sites in catalytic ammonia synthesis over metal
           alloys and clusters: A theoretical study
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Alexander R. Cholach Earlier, a theoretical model was suggested to discriminate catalytic sites Mn (each consisting of n adjacent atoms M on the metal surface) according to their undercoordination Σ. It has been shown that the maximum activity of a site Mn (M = Pt, Rh, Ir, Fe, Ru, Re; n = 2, 3, 4) in the catalytic synthesis of ammonia requires the “resonant” Σ, whose major part is inaccessible at perfect planes because of steric restrictions. The current study applies this model to binary alloys and clusters to construct an advanced catalytic site by adjustment of real Σ to the resonance. The catalytic activity of a site Mn has been estimated by the Brønsted-Evans-Polanyi relation with respect to the formation of NH species. It was found that on alloy surfaces, sites M3 and M4 demonstrate synergetic behavior. This suggests that the most active catalyst (Ru or Re) can be improved by its alloying with the least active one (Pt or Rh). In the case of the noble metals, the sites M3 and M4 at 4-, 5-, and 11- atomic clusters are ∼10–103 times more active than such sites at perfect planes, whereas the sites of Ru and Re show the opposite behaviour. The model was verified by comparison of the calculated specific catalytic activities of metals, centers Fe-C7 and Ru-B5, and single crystals with the published data. The superior activity of a catalytic site is generally enabled by its optimal thermodynamics, which is affected deeply by the first coordination shell. A correlation between local structure, thermodynamics, and activity of a site is likely valid for other catalytic systems.Graphical abstractGraphical abstract for this article
       
  • Advanced oxidation process for coke removal: A systematic study of
           hydrogen peroxide and OH-derived-Fenton radicals of a fouled zeolite
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): María V. Morales, Kinga Góra-Marek, Hermen Musch, Antonio Pineda, Blaine Murray, Stelios Stefanidis, Lorena Falco, Karolina Tarach, Ekaterina Ponomareva, Jan Henk Marsman, Ignacio Melián-Cabrera The regeneration process of a fouled catalyst typically involves treatments at high temperature which often cause irreversible damages on the catalyst’s properties. In this work, Fenton chemistry-derived OH species, and H2O2, are proposed as oxidizing agents to reactivate a porous catalyst at mild conditions, below 100 °C. The chosen catalyst is a microporous ZSM-5 zeolite, which is a challenging candidate due to the mass transfer limitations with possible recombination of the hydroxyl radicals; thereby being an obstacle to oxidize organics occluded in the micropores. The organics deposition over a ZSM-5 zeolite during the D-glucose dehydration reaction was confirmed by a number of characterization techniques, which revealed a considerable decrease in the surface area, pore volume and acid site density in the fouled catalyst. By properly selecting the regeneration conditions, reactivation via Fenton or H2O2 was highly effective in terms of removal of the organics as well as recovery of the initial catalytic activity. The properties of the H2O2 treated-zeolite, the optimal treatment in this case study, were preserved with similar structural and textural features and improved acidity. Hot water extraction was ineffective to remove the humins from ZSM-5. Mechanistically, the presence of Fe impurities in the zeolite structure did not allow to discriminate between a homo, heterogeneous, or a direct H2O2 pathway, or a combination of them. The exhibited conversion by the regenerated zeolite was comparable to that of the fresh one.Graphical abstractGraphical abstract for this article
       
  • An intermetallic Pd2Ga nanoparticle catalyst for the single-step
           conversion of CO-rich synthesis gas to dimethyl ether
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Manuel Gentzen, Dmitry E. Doronkin, Thomas L. Sheppard, Jan-Dierk Grunwaldt, Jörg Sauer, Silke Behrens Well-defined Pd/Ga-nanoparticles were prepared and used as a precursor for the methanol active component in a bifunctional syngas-to-dimethyl ether catalyst. In situ X-ray absorption spectroscopy experiments were employed both to unravel the initial formation of the active catalyst phase in reductive H2 atmosphere and to further monitor changes of the nanoparticles under conditions of dimethyl ether synthesis at a pressure up to 20 bar (250 °C). The catalytic studies were conducted using simulated biomass-derived, CO-rich syngas in a continuous-flow reactor, with the bifunctional catalyst offering the two types of active sites, i.e. for methanol synthesis (Pd/Ga nanoparticles) and its subsequent dehydration (γ-Al2O3), in close proximity. As compared to the conventional Cu/Zn-based reference catalyst prepared via a similar procedure, the Pd/Ga-based catalyst showed a promising activity together with a notable stability with time on stream and a high temperature tolerance (up to 300 °C). A kinetic model which considers the individual reactions involved in direct DME synthesis based on power law equations was used to fit the experimental data, and the apparent activation energies were compared to the Cu/Zn-based catalyst.Graphical abstractGraphical abstract for this article
       
  • Xylene isomerization side reactions over Beta zeolite: Disproportionation
           and transalkylation of C8 aromatics and toluene
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Qian Shi, Jonathan C. Gonçalves, Alexandre F.P. Ferreira, Marta G. Plaza, Alírio E. Rodrigues An experimental and parametric behavior study of disproportionation and transalkylation between C8 aromatics and toluene were carried out over mono-functional acid Beta zeolite with a SiO2/Al2O3 ratio of 35 (BEA35). The experiments were performed in liquid phase under the following conditions: 453, 473, and 493 K and 2.1 MPa. Ethylbenzene disproportionation and ethylbenzene-toluene transalkylation were identified as the main side reactions; therefore, the kinetics of both reactions were estimated. Both reactions were verified to be second-order with no signs of competition for the adsorption sites under the studied conditions. Additionally, ethylbenzene disproportionation and ethylbenzene-toluene transalkylation, undergo through a deethylation-ethylation mechanism, the activation energies were 66 and 57 kJ/mol respectively. Furthermore, the existence of parallel reactions, as well as the feed concentration, showed no effect on the p-diethylbenzene selectivity. Selectivity towards the para-isomer was observed only at very low conversions. Finally, an analytical solution was developed for the system showing excellent agreement with the experimental data.Graphical abstractGraphical abstract for this article
       
  • Comparison between the catalytic and photocatalytic activities of Cu/Al2O3
           and TiO2 in the liquid–phase oxidation of methanol–ethanol mixtures:
           Development of a kinetic model for the preparation of catalyst
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Francisco José Morales-Leal, Javier Rivera De la Rosa, Carlos J. Lucio-Ortiz, Diana Bustos Martínez, David A. De Haro Del Rio, Marco A. Garza-Navarro, Daniela Xulú Martínez-Vargas, Carlos D. Garcia This work presents the preparation and characterization of copper supported on gamma alumina (γ–Al2O3) as a catalyst and compared with the photocatalytic activity of titania (TiO2) in the oxidation of methanol and ethanol mixtures; the ratio of both alcohols in the mixture was according to the commercial alcoholic beverages. In order to understand the thermal transformations of Cu/Al2O3 catalyst, a kinetic model of its synthesis has been developed and analyzed in terms of the oxidation of the precursor CuCl2∙2H2O impregnated onto Al2O3 to form CuO/Al2O3, and also its reduction to form the metallic copper supported on alumina (Cu/Al2O3) catalyst. The sequence of reactions was considered according to the X–ray diffraction (XRD) at different temperatures and thermal characterizations. The kinetic parameters revealed how the alumina support intervened in some steps to form the catalyst through chemical metal–support interactions. It was also verified that during the chemical changes that the active phase undergoes, its good dispersion is maintained on the support and the activation energy values of the model can predict that these metal–support chemical interactions were also preserved from the salt added to the formation of elementary copper. These kinetic model’s predictions were accurately demonstrated by High–resolution transmission electron microscopy (HRTEM) micrographs and X–ray photoelectron spectra (XPS) techniques, where the appearance of the copper aluminate phase (CuAl2O4) is an evidence of the metal–support interaction, which could have contributed to the elementary copper nanoparticles formation and the catalytic activity as an active phase in the oxidation of alcohols. Cu/Al2O3 catalyst showed a higher yield of acetic acid from ethanol than formic acid from methanol. In comparison, the TiO2 in the photocatalytic oxidation presented a higher yield of formic acid from methanol than acetic acid from ethanol. A similar behavior was observed in the oxidation tests of each alcohol separately, since, the photocatalytic oxidation of methanol, using TiO2, showed nearly the 100% of selectivity in the formation of formic acid from methanol, and the Cu/Al2O3 catalyst exhibited similar results but, in this case, the selectivity towards to acetic acid from ethanol. Stable acetate intermediates detected by FTIR in ethanol oxidation to acetic acid on Cu/Al2O3 showed that this oxidation proceeds via acetaldehyde intermediates.Graphical abstractGraphical abstract for this article
       
  • Structured microreactor with gold and palladium on titania: Active,
           regenerable and durable catalyst coatings for the gas-phase partial
           oxidation of 1-butanol
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Yaseen Khan, Minna Marin, Tiia Viinikainen, Juha Lehtonen, Riikka L. Puurunen, Reetta Karinen Structured microreactors coated with catalytically active porous layers have emerged as a promising replacement for conventional reactors because they are inherently safe to operate in nearly isothermal conditions within the kinetic regime. Bio-based 1-butanol is commonly produced by acetone-butanol-ethanol (ABE) fermentation and is considered an important platform chemical that will benefit in the share of value-added chemicals through the development of new catalytic processes. In this study, monometallic gold (Au) and palladium (Pd), as well as bimetallic Au-Pd nanoparticles, supported on titania (TiO2) were prepared by a sol-immobilization method, characterized, coated on structured microreactor plates and tested for their catalytic activity in the gas-phase partial oxidation of 1-butanol to n-butyraldehyde. A customized structured catalyst testing microreactor was used. The average noble metal particle size for the catalyst coatings was determined to be approximately 3.6 nm for Au and Au-Pd catalysts, and the noble metal nanoparticles were evenly distributed. The catalyst coating was 17 ± 7 μm in thickness. The studied coated catalysts (TiO2, Au/TiO2, Pd/TiO2, and Au-Pd/TiO2) were all active for the partial oxidation of 1-butanol. The Au/TiO2 (0.6 wt%) catalyst showed the highest yield (20%) of n-butyraldehyde at 300 °C. The introduction of Pd onto Au/TiO2 or TiO2 shifted the product distribution at 250 °C towards retro-hydroformylation and oxidation products (propene, carbon monoxide and carbon dioxide). All of the coated catalysts that were tested were mechanically stable. The nano Au/TiO2 could be regenerated in situ and showed reproducible activities and yields in over 50 test runs. Structured microreactors coated with gold nanoparticles supported on titania show promise as a reusable and mechanically stable device for the process development of n-butyraldehyde production in ABE fermentation plants.Graphical abstractGraphical abstract for this article
       
  • Tailoring the structure and acid site accessibility of mordenite zeolite
           for hydroisomerisation of n-hexane
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Jana Pastvova, Radim Pilar, Jaroslava Moravkova, Dalibor Kaucky, Jiri Rathousky, Stepan Sklenak, Petr Sazama Mordenite zeolites with diffusion-restricted access to the acid sites located in mono-dimensional 12-ring channels and 8-ring side pockets have found broad applications as catalysts for hydroisomerisation of linear C5 and C6 alkanes and other highly relevant acid-catalysed processes. The accessibility of the porous structure of mordenite (MOR) zeolite is traditionally enhanced by dealumination, but this is invariably connected with a dramatic reduction in the aluminium content and corresponding concentration of the acid sites in the zeolites. Here we describe the preparation of MOR zeolite with high micropore volume, three-dimensional supermicropores (d ∼ 7.5 Å) and good acid site accessibility by concurrent extraction of Si and Al using postsynthesis fluorination-alkaline-acid treatment. The concurrent extraction of Si and Al enables formation of more developed supermicroporous structure and preservation of the molecular Si/Al. The procedure yields MOR with a crystalline structure in which the Si/Al ratio and the micropore volume can be tailored (Si/Al from ∼ 6, VMI up to 0.25 cm3.g−1) by the chemical conditions of the treatment. The Al-rich 3D supermicroporous structure with accessible Brønsted and Lewis active sites provides strongly enhanced activity, selectivity and long-term catalytic stability in the transformation of n-hexane into the corresponding branched isomers.Graphical abstractGraphical abstract for this article
       
  • Experimental and theoretical studies of a greener catalytic system for
           saturated hydrocarbon chlorination composed by trichloroisocyanuric acid
           and a copper(II) compound
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Isis L. Melo, Leonardo M. Lube, Eduardo S. Neves, Wagner S. Terra, Christiane Fernandes, Carlos R.R. Matos, Roberto W.A. Franco, Jackson A.L.C. Resende, Daniel C.A. Valente, Bruno A.C. Horta, Thiago M. Cardozo, Adolfo Horn We are describing herein a new environmentally friendly catalytic system able to convert cyclohexane to chlorocyclohexane with 100% selectivity. The method was also applied to the chlorination of n-hexane and adamantane. The catalytic system employs thichloroisocyanuric acid (TCCA) as halogenating agent and a mononuclear copper(II) complex [Cu(BPAH)(H2O)](ClO4)2, 1, as catalyst (BPAH = 1,4-bis(propanamide)homopiperazine), whose molecular structure was solved by monocrystal X-ray diffraction. For cyclohexane, at a ratio catalyst:substrate:TCCA of 1:1000:333, the system reached a conversion of 32.0 ± 1% at 25 °C and 44.7 ± 0.4% at 50 °C, with 100% selectivity for chlorocyclohexane. With n-hexane, a similar conversion was observed at 50 °C, resulting in mixture of monochlorides. Employing adamantane as substrate, the isomers 1-chloroadamantane and 2-chloroadamante were preferentially formed, together with traces of dichloroadamantane. EPR and ESI-(+)-MS analyses indicate the formation of a Cu-hypochlorite intermediate species, which is supported by theoretical calculations.Graphical abstractGraphical abstract for this article
       
  • Enhanced liquid phase catalytic hydrogenation reduction of bromate over
           Pd-on-Au bimetallic catalysts
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Juan Zhou, Xin Zhou, Liyuan Li, Quanyuan Chen Pd-Au/TiO2 bimetallic catalysts with varied Au contents were prepared by the sequential photocatalytic deposition method and the liquid phase catalytic hydrogenation reduction of bromate over these catalysts was investigated. The catalysts were characterized using X-ray diffraction, transmission electron microscope, UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, H2 chemisorption and energy dispersive spectroscopy. Characterization results showed that Pd atoms were site-deposited on the surface of varied size Au cores and formed Pd-on-Au core-shell like bimetallic nanoparticles on TiO2. The bimetallic catalysts showed higher Pd dispersions and more exposed active sites than that of Pd/TiO2, and the amount of exposed active sites first increased then decreased with Au content. For a similar Pd loading, the bimetallic catalyst exhibited volcano-shape activity as a function of Au loading and the highest activity was identified on Pd-Au(1.0)/TiO2 with Au core size around 8.4 nm. In addition, the catalytic reduction of bromate could be well-fitted by the Langmuir-Hinshelwood model, reflecting an adsorption controlled mechanism.Graphical abstractThe catalytic bromate reduction TOF first increased and then decreased with Au core size.Graphical abstract for this article
       
  • The effect of tungsten doping on the catalytic activity of α-MnO2
           nanomaterial for ozone decomposition under humid condition
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Yajie Yang, Jingbo Jia, Yang Liu, Pengyi Zhang Ozone is a universal air pollutant and its stable decomposition under humid condition is still a challenge. In this work, the effect of tungsten doping on the activity of α-MnO2 for ozone decomposition was first investigated. Tungsten was doped into MnO2 with addition of tungstate in a hydrothermal reaction solution. The as-synthesized catalysts were characterized by XRD, SEM, TEM, BET, XPS, ICP-AES, Raman, H2-TPR, O2-TPD, NH3-TPD and EPR. The results indicated that doping of tungsten made the morphology change from nanorods to nanoparticles with great increase of specific surface area. In addition, more oxygen vacancies were formed, and the surface acidity was greatly enhanced, accordingly the tungsten-doped MnO2 exhibited enhanced activity and stability at room temperature under dry and particularly under humid condition (RH = 65%). It indicates that the doping with a high valence metal such as W6+ into MnO2 is a promising method to obtain efficient ozone-decomposition catalyst.Graphical abstractGraphical abstract for this article
       
  • Promotional effect of Al addition on the Co/ZrO2 catalyst for dry
           reforming of CH4
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Jung-Hyun Park, Suyeon Yeo, Iljeong HeO, Tae-Sun Chang The dry reforming of methane (DRM) was performed on the Al-promoted CoAl(x)/ZrO2 catalysts (x = 0 − 2 wt.%). The addition of a small amount of Al led to an apparent promotional effect on the catalytic activity and stability of the Co-based catalyst. The largest promotional effect was observed for the Co/ZrO2 catalyst with 1 wt.% of Al loading. Although the Co/ZrO2 catalyst exhibited considerable catalytic activity, it was rapidly deactivated during the DRM, while the Al-promoted catalysts exhibited a stable catalytic activity. The addition of appropriate amount of Al species might be caused the strong interaction with the cobalt species at either the ZrO2 surface or near the interfacial region. Thus, the Al promoter led to the enhancement of the catalytic performance of Co/ZrO2 catalyst system by acting as a structural stabilizer.Graphical abstractAddition of an appropriate amount of Al to the Co/ZrO2 catalyst enhance the oxidation resistance of active cobalt species during the dry reforming of methane.Graphical abstract for this article
       
  • Effects of metal or metal oxide additives on oxidative coupling of methane
           using Na2WO4/SiO2 catalysts: Reducibility of metal additives to manipulate
           the catalytic activity
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Sangseo Gu, Hyung-Suk Oh, Jae-Wook Choi, Dong Jin Suh, Jungho Jae, Jungkyu Choi, Jeong-Myeong Ha The oxidative coupling of methane using silica-supported Na2WO4 (Na2WO4/SiO2) catalysts is observed by adjusting additives in order to understand the roles of additives and to design more efficient catalysts. By observing the effects of additives on the catalytic OCM activity of Na2WO4/SiO2 catalysts, the reducibility of metal additives, quantified by the standard reduction potentials, is observed to improve the methane conversion and olefin selectivity, indicating that the active sites of activating methane and dehydrogenating paraffin are identical. The supply of oxygen atoms from more easily reducible additives to tungsten oxide manipulate the OCM activity as described by the standard reduction potentials of the additives. The crystal and electronic structures of the catalysts depend on the additives, which can also be used to adjust the catalytic activity.Graphical abstractGraphical abstract for this article
       
  • Deposition–precipitation approach for preparing core/shell SiO2@Ni-Rh
           nanoparticles as an advanced catalyst for the dehydrogenation of
           2-methoxycyclohexanol to guaiacol
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Junbo Feng, Wei Jiang, Caicai Yuan, Xiancai Shi, Kai Zang, Yadong Zhang A novel core/shell nano-bimetallic catalyst SiO2@Ni-Rh was successfully prepared by deposition–precipitation method, using liquid ammonia as a precipitating agent. SEM, TEM, XRD, XPS, H2-TPR, H2-TPD and adsorption/desorption of nitrogen were employed to systematically investigate the surface morphology, size, chemical composition, reducibility, Ni dispersion and structure of the as-synthesized nanoparticles. It is found that the nickel and rhodium are uniformly dispersed on the silica surface to form core/shell SiO2@Ni-Rh nanoparticles with Ni atoms and Rh atoms as the outer shell and SiO2 as the core, which possess high dispersion of Ni on the surface and high specific surface area (234.063 m2/g) of the catalyst with the mean particle size of ca. 130 nm. The dehydrogenation of 2-methoxycyclohexanol to guaiacol was used as the model reaction for evaluating the catalytic activity of the as-synthesized core/shell various Ni and Rh-containing bimetallic nanoparticles in a tubular stainless steel reactor. SiO2@15Ni-0.4Rh nanoparticles have exhibited remarkable catalytic performance, with 98.3% conversion and 93.6% selectivity of guaiacol, due to high dispersion of metal nanoparticles and synergistic effect of bimetallic Ni-Rh over the special core/shell SiO2@Ni-Rh by the addition of rhodium. Furthermore, turn over frequency value of SiO2@15Ni-0.4Rh nanoparticles achieves 0.47 s−1, showing high catalytic efficiency. In general, the dehydrogenation of 2-methoxycyclohexanol over the core-shell-like SiO2@Ni-Rh nanoparticles in a continuous fixed-bed reactor is a more promising, high atom economy, high efficient, easy separation, environmental friendliness, green synthetic pathway of guaiacol.Graphical abstractSchematic illustration of the formation of core/shell SiO2@Ni-Rh nanoparticles and their catalytic activity.Graphical abstract for this article
       
  • Nanocarbons as platforms for developing novel catalytic composites:
           overview and prospects
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Yen Nan Liang, Wen-Da Oh, Yongmei Li, Xiao Hu Nanocarbons (e.g. graphene, carbon nanotubes, ordered mesoporous carbon, carbon nanofiber, etc.) are widely regarded as promising platforms for developing novel catalytic composites. These catalytic nanocarbon composites have performed exceptionally well in various catalysis processes including chemical catalysis, photocatalysis, and electrocatalysis. This is contributed by their unique intrinsic and extrinsic properties such as high graphitization degree, versatile surface chemistry, and novel morphology. In this review, we provide a short overview on the recent status of the nanocarbons used for preparing various novel catalytic composites. The criteria for developing a high performance nanocarbon composites are assessed and the challenges are critically identified. Finally, we discuss potential future research directions in this field which include developing robust fabrication methodologies, improving the interface and charge transfer, improving the durablity of the catalyst, minimizing the environmental impact, and investigation by advanced characterization methods and modelling.Graphical abstractGraphical abstract for this article
       
  • Ni/SIRAL-30 as a heterogeneous catalyst for ethylene oligomerization
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Maeum Lee, Ji Woong Yoon, Youngmin Kim, Ji Sun Yoon, Ho-Jeong Chae, Yo-Han Han, Dong Won Hwang The oligomerization of ethylene is an important catalytic process for the production of higher olefins, and is also a key step for jet-fuel production from bioethanol. We herein investigated the use of Ni/SIRAL-30 as a heterogeneous catalyst for ethylene oligomerization, as it can be prepared easily and cheaply by the simple impregnation of a Ni precursor on a commercial SIRAL-30 support with a high Brønsted acid site (BAS) density. Pyridine-infrared spectroscopy confirmed that proton species in the bridge-type Si-OH-Al frameworks of SIRAL-30 were partially exchanged with Ni2+ cations without interfering with the Al3+ sites. In addition, the Ni species following catalyst calcination under air and pretreatment with N2 was identified to be the isolated Ni2+ by XPS, EXAFS and CO adsorption. The Ni/SIRAL-30 catalyst gave almost complete ethylene conversion and stability over 100 h at 200 °C, 10 bar pressure, and at a weight hourly space velocity of 0.375 h−1 during continuous ethylene oligomerization. A Ni loading of 4 wt% on SIRAL-30 was optimal for both ethylene conversion and for maximizing the proportion of C10+ products formed, while the pretreatment of Ni(4 wt%)/SIRAL-30 at 550 °C under N2 resulted in the best catalytic activity. Although a degree of deactivation was observed due to the adsorption of heavy oligomers, the initial catalytic activity was restored by heating the used catalyst at 550 °C under air. These results confirm that the Ni(4 wt%)/SIRAL-30 catalyst is both recyclable and an efficient heterogeneous catalyst for continuous ethylene oligomerization.Graphical abstractGraphical abstract for this article
       
  • Structural, electronic and catalytic properties of palladium nanoparticles
           supported on poly(ionic liquid)
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Nathália M. Simon, Gabriel Abarca, Jackson D. Scholten, Josiel B. Domingos, David Mecerreyes, Jairton Dupont The structural, electronic and support effect on palladium nanoparticles (Pd NPs) prepared by sputtering deposition and chemical reduction of a Pd(II) precursor in/on a poly(ionic liquid) (PIL) was investigated in the selective hydrogenation of α,β-unsaturated carbonyl compounds and dienes. Sputtering deposition generates naked NPs with a narrow size distribution (3.2–3.8 nm) that are predominantly composed of Pd(0) (85–100%). Conversely, chemical reduction produces PIL-covered NPs with almost twice the average size (6.6 nm) and only 15% Pd(0). Regard the catalytic performance, support composition (by ionic liquid (IL) addition or not) and NP location are decisive. The best activity and selectivity was obtained with imprinted Pd NPs on a PIL/IL mixture (D-MPIL.NTf2/IL-Pd catalyst). A kinetic investigation was conducted using 2-cyclohexen-1-one (CHN) and D-MPIL.NTf2/IL-Pd catalyst revealing that this reaction follows the Langmuir-Hinshelwood mechanism. Enthalpies obtaining from a Van't Hoff plot show that the adsorption of the CHN substrate on the surface of the PIL-Pd catalyst is an exothermic process (-9 kJ mol−1), whereas H2 adsorption occurs by an endothermic process (12 kJ mol−1). This distinct behavior is consistent with the rate determining step proposed, in which the independent adsorption of reagents is followed by the hydrogenation of a π-allyl intermediate on the catalyst surface.Graphical abstractGraphical abstract for this article
       
  • Controlled manipulation of selectivity between O- versus C-alkylation in
           methylation of phenol using ZrO2-WO3- SiO2 catalysts
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Kalpesh H. Bhadra, Ganapati D. Yadav Anisole and o-cresol are very important chemicals which could prepared from phenol using different catalytic routes favoring either O- or C-alkylation. In the methylation of phenol with methanol, the selectivity to either anisole or o-cresol could be manipulated using a suitable tailor-made catalyst having a proper balance of acidic and basic sites. In the current work, a series of compositions based on zirconium, tungsten and silicon oxides (xZrO2-yWO3-SiO2) were prepared and employed as catalysts in fixed bed methylation of phenol. In the absence of silica as support, methylation of phenol over 20% WO3-ZrO2 and 40% WO3-ZrO2 favored predominantly C-alkylated product o-cresol. Among various combinations 10% ZrO2-30% WO3-SiO2 gave the best results and selectivity to the desired product anisole. Effect of various parameters affecting selectivity to anisole or o-cresol were studied systematically. The mechanism of formation of different products with reference to catalyst structure and functionality was explored in detail. The process parameters could be optimized to get the desired product. Thus, the proper choice can be made to choose the selectivity of O-versus C-alkylation using a single catalyst. The time on stream study was carried out for 16 h to find that the catalyst was stable and could be regenerated.Graphical abstractGraphical abstract for this article
       
  • B+bond+cleavage+of+arylboronic+acids&rft.title=Applied+Catalysis+A:+General&rft.issn=0926-860X&rft.date=&rft.volume=">Size-tunable ZnO nanotapes as an efficient catalyst for oxidative
           chemoselective CB bond cleavage of arylboronic acids
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Shreemoyee Phukan, Abhijit Mahanta, Md. Harunar Rashid Herein, we report a simple but effective chemical approach for the synthesis of size-tunable ZnO nanotapes by precipitation method in the presence of phytochemicals present in the flower extract of Lantana camara plant. The electron microscopic study confirmed that the size of ZnO nanotapes can be systematically controlled by varying the concentration of either flower extract or metal ions and the flower extract played the key role in controlling the growth of ZnO nanotapes. The phase and crystalline analysis was carried out by X-ray diffraction method which indicated that ZnO nanostructures are highly crystalline in nature and are free from any impurities. The synthesized ZnO nanostructures exhibited interesting optical properties as investigated by UV–vis absorption and photoluminescence spectroscopy. Further the surface functionalities affect the optical properties of ZnO nanostructures which possess relatively strong UV emissions; a blue emission and a green emission. The synthesized ZnO nanostructures showed excellent catalytic properties in the ipso-hydroxylation of different aryl/ hetero-arylboronic acid to phenol in a relatively greener reaction conditions. These catalysts are highly stable and are re-usable upto six cycles of ipso-hydroxylation without losing its catalytic properties.Graphical abstractGraphical abstract for this article
       
  • Catalytic decomposition of ammonia to COx-free hydrogen over Ni/ZSM-5
           catalysts: A comparative study of the preparation methods
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Zhong-Pan Hu, Chen-Chen Weng, Chong Chen, Zhong-Yong Yuan A series of Ni/ZSM-5 catalysts are prepared by the methods of wet impregnation (IM), deposition-precipitation (DP), solid state ion exchange (SSIE), and modified solid state ion exchange (MSSIE), and used for catalytic decomposition of ammonia to COx-free hydrogen. Their physicochemical properties are characterized by XRD, N2 sorption, TEM, NH3-TPD, H2-TPR, solid-state NMR, and XPS techniques. It is revealed that the preparation methods could obviously influence the Ni species and catalytic performance of Ni/ZSM-5 catalysts, and the catalyst prepared by MSSIE method exhibits the best catalytic activity due to the presence of strong metal-support interaction between highly dispersed Ni nanoparticles and ZSM-5 support. The stability testing results showed almost no activity loss over Ni/ZSM-5(MSSIE) catalyst at 650 °C for 60 h, indicating a very promising catalyst for ammonia decomposition.Graphical abstractGraphical abstract for this article
       
  • The effect of ionic liquid on alumina supported copper catalysts for the
           competitive hydrogenation of octanal in the presence of octene
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Letisha Naicker, Holger B. Friedrich, Alisa Govender, Pheladi Mohlala The influence of 1-butyl-3-methylimidazolium bis(trifluromethanesulfonyl)imide ([BMIM][NTf2]) on Cu/γ-Al2O3 was investigated for the competitive hydrogenation of octanal in the presence of octene in a continuous flow reactor. The role of the solid catalyst was investigated by comparing the activities of one-step (N15Cu) vs two step (2N15Cu) wet impregnated catalyst. Characterization techniques included nitrogen physisorption, temperature programmed studies, electron microscopy and X-Ray Photoelectron Spectroscopy which were used to determine the catalyst properties and metal-ionic liquid interaction of the uncoated and IL coated catalysts. The Cu SCILL catalyst (solid catalyst with an ionic liquid layer) showed enhanced catalytic performance as compared to the uncoated catalyst. Under optimized conditions, the 2N15Cu SCILL catalyst favoured the desired hydrogenation of the octanal, whilst minimizing the undesired octene hydrogenation. The octene conversion decreased from 26% to 6% over the SCILL catalyst. The presence of the ionic liquid also increased the selectivity towards the desired product, 1-octanol, from 93.5% over the uncoated catalyst to 99.8% over the SCILL catalyst. Investigation into the interaction between the copper and the ionic liquid revealed that the ionic liquid is physically adsorbed onto the catalyst’s surface, and induced changes in the SCILL catalysts surface acidity, BET surface area and hydrogen-metal interaction. It seems likely that the thermal and chemical properties of the ionic liquid also contributed to the SCILL catalyst behaviour, for example, the polar nature of the ionic liquid favours the diffusion of octanal as opposed to octene within the ionic liquid layer. This results in a greater selectivity towards CO hydrogenation which is desired.Graphical abstractGraphical abstract for this article
       
  • CuOx/CeO2 catalyst derived from metal organic framework for reverse
           water-gas shift reaction
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Maria Ronda-Lloret, Soledad Rico-Francés, Antonio Sepúlveda-Escribano, Enrique V. Ramos-Fernandez Herein, we have studied an alternative route for preparing CuOx/CeO2 catalysts using metal organic frameworks (MOFs) as precursors. Usually, CuOx/CeO2 materials are prepared by wet impregnation of ceria support. In this study, we have impregnated a Cu-MOF with a ceria precursor and then pyrolized the impregnated MOF using different conditions and procedures. The prepared catalysts have been characterized by using a wide range of techniques such as XRD, XPS, Raman, and TPR. We have found that the pyrolysis method determines the dispersion of the oxidized copper species on the ceria surface what, in turn, controls the catalytic activity and selectivity of the catalysts in the reverse water-gas shift (RWGS) reaction. We have compared the behavior of the MOF-derived catalysts against an optimized catalyst prepared by a conventional method (wet impregnation), finding that the MOF-derived catalyst shows better catalytic performance.Graphical abstractGraphical abstract for this article
       
  • The superior performance of Nb-modified Cu-Ce-Ti mixed oxides for the
           selective catalytic reduction of NO with NH3 at low temperature
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Xiaoqiang Wang, Yue Liu, Qingji Ying, Weiyuan Yao, Zhongbiao Wu In this paper, a series of Nb modified Cu-Ce-Ti mixed oxides (NbyCCT) were synthesized using wetness impregnation method for the selective catalytic reduction of NO with ammonia (NH3-SCR). The activity tests indicated that NbyCCT catalysts had shown superior SCR performances. Among which, Nb0.05CCT catalyst exhibited a NO conversion of more than 90% within a broad operation temperature window (180–360 °C) under the GHSV of 40,000 h−1. After that, corresponding characterizations were performed to correlate the physical structures and surface properties to catalytic performances. These results revealed that the strong interactions among the active phases induced by Nb addition could not only enhance the redox property of the catalysts but also inhibit the over-oxidation of NH3, which would be beneficial to SCR performance within a wide temperature range and good reaction selectivity. Furthermore, DRIFTS results suggested that the doping of Nb could promote the formation of NO2, thereby enhancing the “fast” SCR reaction process (Langmuir-Hinshelwood reaction pathway). Moreover, the Nb0.05CCT catalyst showed a better sulfur tolerance compared to Nb free catalyst that over 85% NO conversion could be retained after 12 h SCR reaction in the presence of SO2 and H2O.Graphical abstractGraphical abstract for this article
       
  • Selective production of 1,3-butadiene in the dehydration of 1,4-butanediol
           over rare earth oxides
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Yuchao Wang, Daolai Sun, Yasuhiro Yamada, Satoshi Sato Vapor-phase dehydration of 1,4-butanediol and 3-buten-1-ol to produce 1,3-butadiene was investigated over rare earth oxides such as Lu2O3, Yb2O3, Tm2O3, Er2O3, and Sc1.0Yb1.0O3. In the dehydration of 3-buten-1-ol, heavy rare earth oxides such as Lu2O3, Yb2O3, and Er2O3 showed high catalytic performance for the selective formation of 1,3-butadiene with producing small amount of propylene whereas acidic catalysts such as alumina decomposed 3-buten-1-ol into propylene. In particular, over Yb2O3 calcined at 800 °C, 3-buten-1-ol was converted with a yield of 1,3-butadiene higher than 95% at 340 °C. In the dehydration of 1,4-butanediol, furthermore, we developed an efficient catalytic system: 1,3-butadiene was produced via an intermediate, 3-buten-1-ol, over Yb2O3 with an excellent yield of 96% at 360 °C and a high contact time of 2.26 h. Yb2O3 successfully inhibited the major side reaction such as decomposition of 3-buten-1-ol to propylene and provided the selective production of 1,3-butadiene from 1,4-butanediol.Graphical abstractGraphical abstract for this article
       
  • A comparative study on Ce–Pr and Ce–Mn mixed oxide catalysts toward
           soot catalytic combustion
    • Abstract: Publication date: 25 July 2018Source: Applied Catalysis A: General, Volume 562Author(s): Bing Zhou, Kang Xi, Li-Jia Fan, Ying Zhou, Yue Wang, Qiu-Lian Zhu, Han-Feng Lu CePr and CeMn mixed oxide catalysts were synthesized by inserting Pr and Mn atoms into CeO2. Catalytic performance on soot combustion was investigated, and several characterizations were carried out using X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area analysis, H2 temperature-programmed reduction, and X-ray diffraction. Results show that a cubic fluorite structure solid solution can be formed with Pr and Mn doped into CeO2 lattice. Three oxygen species, namely, lattice oxygen OI (O2−), defect oxygen species OII (O2−, O22−, and O−), and hydroxyl-like groups and adsorbed molecular water OIII, exist in the solid solution structure. In general, the defect oxygen species OII is responsible for soot combustion. CePr exhibits fast oxidation rate because of the presence of open oxygen migration channel (OI↔OII↔OIII), and reactive oxygen species OII can continue to be replenished. CeMn possesses a large amount of surface active oxygen, which results in excellent low-temperature catalytic activity.Graphical abstractGraphical abstract for this article
       
  • Improving activity of ZSM-5 zeolite catalyst for the production of
           monomeric aromatics/phenolics from hydrolysis lignin via catalytic fast
           pyrolysis
    • Abstract: Publication date: Available online 6 July 2018Source: Applied Catalysis A: GeneralAuthor(s): Hooman Paysepar, Kasanneni Tirumala Venkateswara Rao, Zhongshun Yuan, Hengfu Shui, Chunbao (Charles) Xu This work aimed to further enhance the activity of ZSM-5 zeolite catalyst for the production of monomeric aromatics/phenolics from hydrolysis lignin via catalytic fast pyrolysis. To this end, various treatment approaches including acidification with H2SO4 and H3PO4 and metal (Ni) loading were performed on the ZSM-5 zeolite. Catalytic fast pyrolysis (CFP) of hydrolysis lignin (HL) was conducted at 450 ᵒC using ZSM-5 zeolites with various strengths of acidity (ZSM-5 and Ni-ZSM-5 with moderate Lewis and Bronsted sites, H2SO4-ZSM-5 and H3PO4-ZSM-5 with more Bronsted sites). The results show that the yield of monomeric aromatic compounds increased considerably by increasing the Bronsted acid site and total acidity of the catalyst. With the best catalyst, H2SO4-ZSM-5, the total monomeric aromatics/phenolics yield increased to 151 mg/g-HL, compared to 68 mg/g-HL without catalyst, 84 mg/g-HL with ZSM-5, 96 mg/g-HL with H3PO4-ZSM-5, and 85 mg/g-HL with Ni-ZSM-5. The H2SO4-ZSM-5 demonstrated to be thermally stable and has superb resistance to carbon/coke deposition, owing to its microporous structure, relative large BET surface area and presence of strong Bronsted acid sites.Graphical Graphical abstract for this article
       
  • Highly Selective Production of Olefins from Syngas with Modified ASF
           Distribution Model
    • Abstract: Publication date: Available online 4 July 2018Source: Applied Catalysis A: GeneralAuthor(s): Fei Yu, Tiejun Lin, Xinxing Wang, Shenggang Li, Yongwu Lu, Hui Wang, Liangshu Zhong, Yuhan Sun The Fischer-Tropsch to olefins (FTO) process is a promising alternative non-petroleum route to produce value-added olefins. In this study, Co2C nanoprisms formed via the CoMn spinel structure were used as the active phase for the FTO reaction and the product distribution was thoroughly investigated. A break from the traditional ASF model was found with much lower methane selectivity than that predicted by the ideal ASF law. In addition, the as-obtained hydrocarbons were mainly concentrated in the range of C2 to C12 with the C2-12 selectivity as high as 91% while the C13+ selectivity as low as 5%, indicating a much narrower distribution, which was rarely observed in the FT reaction. Moreover, ~86% of the hydrocarbon products were olefins with very high olefin to paraffin ratios, suggesting a promising route for the selective production of olefins directly from syngas. A modified ASF distribution model was proposed with three different chain growth probabilities to rationalize the non-ASF phenomenon.Graphical abstractGraphical abstract for this articleCo2C nanoprisms benefited for highly selective production of olefins from syngas with modified ASF distribution model.
       
  • Copper-Gold Nanoparticles Encapsulated Within Surface-Tethered Dendrons as
           Supported Catalysts for the Click Reaction
    • Abstract: Publication date: Available online 4 July 2018Source: Applied Catalysis A: GeneralAuthor(s): Aibolat Koishybay, Daniel F. Shantz The synthesis, characterization, and catalytic testing of copper and copper:gold nanoparticles in melamine-based dendrons supported on SBA-15 is reported. It was found that by first making small gold nanoparticles using the dendrons as templates, stable copper(0) overlayers could then be successfully deposited. These samples were used as catalysts for the click reaction, with the most active samples possessing rates of 8.9 mol triazole produced/(mol copper – hour), nearly 50 times high than literature reports of copper nanoparticles in solution. In constrast, the gold nanoparticles themselves are inert for this reaction, consistent with the copper being deposited as an overlayer on the gold nanoparticles. Copper leaching was shown to be less pronounced for particles formed in the dendrons versus copper simply deposited on SBA-15. Larger dendrons lead to suppressed rates due to diffusion resistance with rates decreasing from 8.9 to 5.2 to 0.69 mole triazole produced/(mole Cu-hour) for G1, G2, and G3 respectively. Infrared spectroscopy was used to monitor the reaction in real time, and provided information about the various surface intermediates formed.Graphical Graphical abstract for this article
       
  • Effect of the operating parameters on the simulation of acetylene
           hydrogenation reactor with catalyst deactivation
    • Abstract: Publication date: Available online 2 July 2018Source: Applied Catalysis A: GeneralAuthor(s): Mohammad Samavati, Habib Ale Ebrahim, Yousef Dorj In the present study, the pseudo-homogeneous and heterogeneous models of fixed bed reactor using Pd − Ag/Al2O3 catalyst for acetylene hydrogenation were simulated. The high compatibility of both models with experimental data was obtained. The effect of operating conditions such as inlet temperature (302, 310 and 318 K), hydrogen/acetylene ratio (1, 1.4, 2 and 2.5), total pressure (15, 20 and 25 bar) and gas flow (270, 300 and 365 m3/h) was calculated on the conversion of acetylene and selectivity of ethylene. The obtained results revealed that the maximum conversion of acetylene was accomplished in an inlet temperature of 318 K, the hydrogen/acetylene ratio of 2.5, total pressure of 25 bar and the gas flow of 270 m3/h. The catalyst deactivation behavior was simulated as functions of time and temperature. To compensate the catalyst deactivation after 6 and 12 months, the effect of temperature enhancement on the acetylene conversion was investigated.Graphical abstractGraphical abstract for this articleOperating condition: Tin = 308 k, PT = 19 bar, H2/C2H2 = 1
       
  • Plasmonic Au-Ag Bimetallic Alloy Nanoparticles decorated ZnO nanorod with
           enhanced photocatalytic activity for ethylene-oxidation
    • Abstract: Publication date: Available online 12 June 2018Source: Applied Catalysis A: GeneralAuthor(s): Huishan Zhai, Peng Wang, Qianqian Zhang, Xiaolei Liu, Zeyan Wang, Yuanyuan Liu, Zhaoke Zheng, Baibiao Huang Au-Ag Bimetallic alloy nanoparticles (NPs) with 5-10 nm diameter modified ZnO nanorod was synthesized via simple photo-deposition procedure. In this work, the photocatalytic ethylene-oxidation activity of ZnO co-decorated by 0.8 wt% Au-Ag alloy was 94.8 times higher than that of pure ZnO, while loaded by single 0.8 wt% Au or Ag NPs was only 17.5 or 26.8 times higher than that of ZnO. Furthermore, the AuAg/ZnO showed significant better stability in five times of tests. Obviously, the AuAg/ZnO exhibits great photocatalytic activity and stability compared to mono-metal loaded ZnO. The as-prepared products were characterized by XRD, SEM, EDS, TEM, UV-vis DRS and photoelectrochemical measurements. Characterization results explained that the Au-Ag NPs modified ZnO showed great visible-light absorption because of the surface plasmon resonance (SPR) effect. Meanwhile, the higher photocurrent density showed the effective carrier separation ability in AuAg/ZnO. Therefore, the cooperative action of plasmonic Au-Ag Bimetallic Alloy NPs and efficient carrier separation capability result in the outstanding photoactivity of ethylene-oxidation.Graphical Graphical abstract for this articleThe excitation of surface plasmon and electron transfer process under the irradiation of UV-vis light.
       
  • Synthesis of solution processed f-CNT@Bi2S3 hybrid film coated linen
           fabric as a free-standing textile structured photo catalyst
    • Abstract: Publication date: Available online 10 June 2018Source: Applied Catalysis A: GeneralAuthor(s): Anam Ali Memon, Alvira Ayoub Arbab, Supriya A. Patil, Naveed Mengal, Kyung Chul Sun, Iftikhar Ali Sahito, Sung Hoon Jeong, Hak Sung Kim A unique metallic carbon hybrid film, synthesized with synchronized distribution of bismuth sulfide (Bi2S3) and exfoliated multiwall carbon nanotubes (MWCNTs), has been proposed for use as freestanding textile electrodes in photo catalysts. The defect-rich morphology of Bi2S3 nanowire decorated MWCNT hybrid enhances the photocatalytic activity, electronic properties, cyclic stability, and electron pathways. The proposed f-CNT@Bi2S3-hybrid linen fabric electrode demonstrated a defect-rich morphology synchronized with high electrical conductivity. These properties greatly enhanced the photocatalytic activity and electron transfer. The high photocatalytic activity is attributed to the synergistic effect of the high electron affinity of MWCNTs and the structural distortion caused by Bi2S3 nanowires. Degradation of methylene blue dye was accelerated owing to the elevated activity of Bi2S3 nanowires, which provides fast absorption of contaminants and reduction of oxidative species. Our proposed system of metallic carbon freestanding textile electrode opens the broad applications of textile-based photochemical devices.Graphical Graphical abstract for this article
       
  • Excellent low-temperature catalytic performance of nanosheet Co-Mn oxides
           for total benzene oxidation
    • Abstract: Publication date: Available online 31 May 2018Source: Applied Catalysis A: GeneralAuthor(s): Xiaolan Zhang, Ye Junhui, Yuan Jing, Cai Ting, Xiao Bei, Liu Zhe, Zhao Kunfeng, Yang Ling, He Dannong A series of CoaMnbOx oxides (a/b = 1:1~7:1) at 500 °C and Co2Mn1Ox at a temperature range of 300-700 °C were prepared by an oxalate co-precipitation method and evaluated of catalytic performance for benzene total oxidation. It is found that Co2Mn1Ox catalyst displays the best activity among all the CoaMnbOx oxides. The typical uniform nanosheet morphology plays a vital role in achieving the relatively high activity of Co2Mn1Ox. A detailed characterization has illustrated that the calcination temperature is also an important factor to influence the structure, physico-chemical properties and thus catalytic performance of Co2Mn1Ox. Co2Mn1Ox calcinated at 300 °C (CM300) presents pretty thin nanosheet and small particle size of 6.6 nm. It displays a better low-temperature catalytic activity than those obtained at temperatures of>300 °C: under the conditions of 20,000 mL·g-1·h-1 and 1500 ppm of benzene, the temperature at 90% conversion of benzene oxidation is 191 °C, which is lower than that of some related reports in the literatures. Furthermore, CM300 performed excellent long-term stability. It is concluded that the superior catalytic performance of CM300 is associated with its relatively large specific surface area, good low-temperature redox property, abundant active oxygen species and active components (Co2+ and Mn4+). Co-Mn oxides will be the potential alternative of precious metals for the removal of volatile organic compounds in the industrial field.Graphical abstractGraphical abstract for this articlefx1
       
  • New Insights on the role of sulfur vacancies on dibenzothiophene
           hydrodesulfurization over MoS2 edges
    • Abstract: Publication date: Available online 28 May 2018Source: Applied Catalysis A: GeneralAuthor(s): Seyyedmajid Sharifvaghefi, Bo Yang, Ying Zheng Experimental and computational studies were performed to investigate the effect of varying sulfur coverage over MoS2 in hydrodesulfurization (HDS) of dibenzothiophene (DBT). Hematite and iron particles were employed as H2S scavengers. MoS2 showed high hydrogenation (HYD) preference in HDS of DBT which was explained by the DFT calculations showing that HYD pathway is more favorable in brim adsorption. The addition of hematite drastically shifted this preference to direct desulfurization (DDS) pathway. DFT calculations showed that MoS2 forms edges with 25% sulfur coverage in presence of hematite. The hydrogen dissociation was found to be energetically unfavorable (deactivated) over the Mo-edge with such sulfur coverage and becomes exothermic (reactivated) only after sigma adsorption of DBT on a vacancy site. In agreement with experimental results, calculations also showed that in the presence of vacancies, the sigma adsorption of DBT and therefore DDS pathway is more favorable. MoS2 with iron particles present, favored the HYD reaction route, however, compared to MoS2 the biphenyl (BP) selectivity increased while the selectivity for isomerized products was reduced. DFT calculations showed that in the presence of iron, Mo-edge has 37% coverage with a vacancy site formed over this edge which explains the higher DDS activity for this catalyst compared to MoS2. A difference was observed in the ability of H2 and H2S in creation of acid sites upon their dissociation at the edges. This was attributed to the difference in S-H bond energies in each molecule and the change in oxidation sate of neighboring Mo atoms.Graphical abstractGraphical abstract for this article
       
  • A dual acidic hydrothermally stable MOF-composite for upgrading xylose to
           furfural
    • Abstract: Publication date: Available online 18 April 2018Source: Applied Catalysis A: GeneralAuthor(s): Amrita Chatterjee, Xijun Hu, Frank Leung-Yuk Lam This work presents the development of a new hybrid material composed of metal-organic-framework, MIL-101 (Cr) and mesoporous tin phosphate nanoparticles. The phosphate groups of the composite impart Brønsted acidity, while the Cr and Sn atoms act as the Lewis acid sites, thus promoting it as a dual acid functionalized material suitable for solid acid catalysis of biomass. Simultaneously, the issues of hydrothermal stability and degradation in acidic medium as faced by pristine MIL-101 (Cr), have been fairly alleviated. In order to demonstrate our claims, the composite has been used as a solid acid catalyst for the dehydration of xylose to furfural. A remarkable performance of 86.7% furfural yield with 92.3% selectivity has been achieved in 180 minutes at 150°C. The composite can sustain minimum of 10 cycles of run while pristine MIL-101 (Cr) loses its functional properties after 4 cycles of run. In presence of 35 ppt NaCl solution, the yield and selectivity improved to 92.4% and 96.6% respectively.Graphical abstractGraphical abstract for this article
       
 
 
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