for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> ENGINEERING (Total: 2417 journals)
    - CHEMICAL ENGINEERING (207 journals)
    - CIVIL ENGINEERING (202 journals)
    - ELECTRICAL ENGINEERING (111 journals)
    - ENGINEERING (1267 journals)
    - ENGINEERING MECHANICS AND MATERIALS (400 journals)
    - HYDRAULIC ENGINEERING (56 journals)
    - INDUSTRIAL ENGINEERING (76 journals)
    - MECHANICAL ENGINEERING (98 journals)

ENGINEERING (1267 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: 14)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 275)
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: 18)
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: 17)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 43)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
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: 9)
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: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Archives of Foundry Engineering     Open Access  
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: 8)
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: 9)
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: 39)
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: 21)
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: 277)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 210)
Composites Part B : Engineering     Hybrid Journal   (Followers: 249)
Composites Science and Technology     Hybrid Journal   (Followers: 194)
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: 19)
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: 33)
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
Catalysis Today
Journal Prestige (SJR): 1.347
Citation Impact (citeScore): 5
Number of Followers: 7  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0920-5861
Published by Elsevier Homepage  [3163 journals]
  • Catalysis Today Special Issue: Catalysis for Sustainable Development,
           Peace and Prosperity
    • Authors: Ganapati D. Yadav; Mannepalli Lakshmi Kantam; Bhalachandra M. Bhanage
      First page: 1
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Ganapati D. Yadav, Mannepalli Lakshmi Kantam, Bhalachandra M. Bhanage


      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2018.03.067
      Issue No: Vol. 309 (2018)
       
  • Effect of calcium addition on Mg-AlOx supported Ni catalysts for hydrogen
           production from pyrolysis-gasification of biomass
    • Authors: Fangzhu Jin; Hongman Sun; Chunfei Wu; Huajuan Ling; Yijiao Jiang; Paul T. Williams; Jun Huang
      Pages: 2 - 10
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Fangzhu Jin, Hongman Sun, Chunfei Wu, Huajuan Ling, Yijiao Jiang, Paul T. Williams, Jun Huang
      Producing hydrogen from catalytic gasification of biomass represents an interesting process to facilitate the development of hydrogen economy. However, the design of catalyst is a key challenge for this technology. In this work, cost-effective Ca added Ni-based catalysts were developed and studied for producing hydrogen with a fixed-bed reactor. The relationship between Ca addition and the performance of catalyst in terms of the yield of hydrogen and catalyst deactivation (metal sintering and coke formation) was studied. The results showed that hydrogen production was largely enhanced when Ca was added, as the yield of hydrogen was enhanced from 10.4 to 18.2 mmol g−1 sample in the presence of Ca-based catalyst. However, the yield and concentration of hydrogen were kept at similar levels with the increase of Ca. By normalizing the yield of hydrogen in relation to the amount of Ni presented inside the catalyst, the hydrogen yield per mole of nickel was increased from 50 g Ni −1(0.1Ca catalyst) to 80 g Ni−1 (0.8Ca catalyst) when the Ca addition was increased from 10 mol% to 80 mol%. TPO-FTIR analysis of the experimented catalysts showed that 0.5 Ca catalyst had the highest amount of coke formation, in particular, most of the deposited carbons were amorphous which could deactivate the catalyst seriously. It is therefore concluded that the addition of cost-effective Ca could enhance the yield of hydrogen from biomass gasification. However, the concentration of Ca in the catalyst needs to be controlled to mitigate the generation of coke on the used catalyst.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2018.01.004
      Issue No: Vol. 309 (2018)
       
  • Mechanistic in-operando FT-IR studies for hydroprocessing of triglycerides
    • Authors: Mohit Anand; Saleem Akthar Farooqui; Jitendra Singh; Hari Singh; Anil Kumar Sinha
      Pages: 11 - 17
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Mohit Anand, Saleem Akthar Farooqui, Jitendra Singh, Hari Singh, Anil Kumar Sinha
      In-operando measurements were carried out for the first time to identify different intermediates and primary products formed during the conversion of lipids for catalytic as well as non-catalytic thermal hydroprocessing. Hydroprocessing of lipids was carried at 280–300 °C temperature, 40–60 bar pressure, 1500 Nl/L H2/Feed ratio and 1 h−1 space velocity in a fixed-bed tubular reactor. A high pressure metallic probe was used for collecting the FTIR spectra under these conditions. Under these conditions although the conversion of triglyceride molecules were complete, the deoxygenation reactions were less than 1%, with 6–7% carbon loss and 17–18% hydrogen loss into the gaseous phase corresponding to propane. In-operando FT-IR studies confirmed that depropanation (propane removal) is the primary reaction during catalytic hydroprocessing of triglycerides, along with formation of intermediates. For thermal hydroprocessing wide range of intermediates – alcohols, alkenes, ketones, anhydrides, ethers, acids, aldehyde and esters – were observed. Such intermediates indicate several undesirable coupling reactions such as CC bond formation, esterification, etherification and ketonization. For catalytic hydroprocessing only selective product intermediates were observed. Triglycerides hydroprocessing over Pd/Al2O3 catalyst predominantly produced carboxylic acid and aldehyde intermediates, along with very weak bands due to aromatics. Pd/C predominantly produced aldehydes with weak bands due to ketones. Sulfided CoMoP/Al2O3 catalyst also produced aldehydes predominantly, but also small quantities of carboxylic acids as intermediates, from trigycerides. IR bands due to alcohols, ethers, aromatics and cyclic ketones were observed at the later stage of reaction over CoMoP(S)/Al2O3 catalyst.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.12.021
      Issue No: Vol. 309 (2018)
       
  • Green catalytic processing of native and organosolv lignins
    • Authors: B.N. Kuznetsov; N.V. Chesnokov; I.G. Sudakova; N.V. Garyntseva; S.A. Kuznetsova; Yu.N. Malyar; V.A. Yakovlev; L. Djakovitch
      Pages: 18 - 30
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): B.N. Kuznetsov, N.V. Chesnokov, I.G. Sudakova, N.V. Garyntseva, S.A. Kuznetsova, Yu.N. Malyar, V.A. Yakovlev, L. Djakovitch
      Two ways of catalytic depolymerization of native and isolated wood lignins are described: the peroxide delignification of hardwood (aspen, birch) and softwood (abies) in the medium of acetic acid – water over TiO2 catalyst and the thermal dissolution of organosolv lignins (ethanol-lignin and acetone-lignin) in supercritical alcohols (ethanol and butanol) over solid Ni-containing catalysts. The catalyst TiO2 in rutile modification has the higher activity in wood peroxide delignification at 100 °C as compared to TiO2 in anatase modification. The results of kinetic studies and optimization of the processes of peroxide depolymerization of hardwood (aspen, birch) and softwood (abies) lignins in the medium of acetic acid – water over catalyst TiO2 (rutile) at mild conditions (≤100 °C, atmospheric pressure) are compared. The catalyst TiO2 initiates the formation of OH and OOH radicals from H2O2 which promote the oxidative fragmentation of wood lignin. In this case, the peroxide depolymerization of softwood lignin, constructed from phenylpropane units of guaiacyl-type proceeds more difficult than the hardwood lignins, mainly containing syringyl-type units. The solid and soluble products of peroxide catalytic delignification of wood under the optimized conditions were studied by FTIR, XRD, GC–MS and chemical methods. Regardless of the nature of wood the cellulosic products have a structure similar to microcrystalline cellulose. The soluble products mainly consist of monosaccharides and organic acids. Aromatic compounds are present only in a low amount which indicates the oxidative degradation of aromatic rings of lignin phenylpropane units under the used conditions of wood catalytic delignification. The processes of thermal dissolution of acetone-lignin and ethanol-lignin from aspen-wood in supercritical ethanol and butanol over Ni-containing catalyst (NiCu/SiO2, NiCuMo/SiO2) are compared. The composition, structure and thermal properties of organosolv lignins were studied with the use of FTIR, GPC, 1H – 13C HSQC NMR, DTA and elemental analysis. The influence of a composition of Ni-containing catalyst on the thermal conversion in supercritical butanol and ethanol of ethanol-lignin and acetone-lignin was established. The highest conversion of lignins (to 93% wt.) in supercritical alcohols and the highest yield of liquid products (to 90% wt.) were achieved at 300 °C in the presence of catalyst NiCuMo/SiO2. Scheme of green biorefinery of wood based on the use of non-toxic and low-toxic reagents (H2O2, H2O, acetic acid, ethanol, butanol) and solid catalysts (TiO2, NiCuMo/SiO2) is suggested.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.11.036
      Issue No: Vol. 309 (2018)
       
  • Benzyl methyl ether production from benzyl alcohol and methanol in
           carbonic water
    • Authors: Hidetaka Nanao; Hiroki Sasaki; Osamu Sato; Aritomo Yamaguchi; Masayuki Shirai
      Pages: 31 - 34
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Hidetaka Nanao, Hiroki Sasaki, Osamu Sato, Aritomo Yamaguchi, Masayuki Shirai
      Synthesis of benzyl methyl ether from benzyl alcohol and methanol in high-temperature carbonic water was studied in a batch reactor. Benzyl methyl ether formation was not observed by reacting benzyl alcohol with only methanol under supercritical conditions at 573K. On the other hand, benzyl methyl ether was formed by the treatment of benzyl alcohol in an aqueous methanol solution at 573K. 12% of benzyl methyl ether yield was obtained in aqueous methanol solution (methanol to water molar ratio of 0.025mol/0.11mol) at 573K in 60min and the yield enhanced to 33% by the addition of 18MPa of carbon dioxide to the aqueous solution. As the etherification is an acid catalyzed reaction, the protons derived from the dissociation of water molecules could be responsible for the etherification of benzyl alcohol in an aqueous methanol solution at 573K. The enhancement of benzyl methyl ether yield by the addition of carbon dioxide in aqueous methanol solution is caused by the increase of the number of protons derived from carbonic acid, which is formed in high-temperature liquid water under high-pressured carbon dioxide.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.11.021
      Issue No: Vol. 309 (2018)
       
  • Spectroelectrochemical analysis of TiO2 electronic states – Implications
           for the photocatalytic activity of anatase and rutile
    • Authors: Marcin Kobielusz; Kacper Pilarczyk; Elżbieta Świętek; Konrad Szaciłowski; Wojciech Macyk
      Pages: 35 - 42
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Marcin Kobielusz, Kacper Pilarczyk, Elżbieta Świętek, Konrad Szaciłowski, Wojciech Macyk
      The information on the electronic structure of nano- and microstructured semiconductors is crucial for their applications in photovoltaics, optoelectronics and photocatalysis. The distribution of intra-bandgap electronic states is one of the most relevant parameters which may be tuned in order to provide desired properties of a photoactive material. We propose the use of a modified spectroelectrochemical method for the characterisation of vacant electronic states distributed close to the edge of the titanium dioxide conduction band. These additional levels localized within the bandgap were semi-quantitatively characterized for several samples made of different polymorphs (or their blends) of TiO2. The applicability of the method for the determination of deep and shallow electron traps was confirmed. A quantitative analysis of the latter was also conducted for the selected samples. The presented approach provides also the information on the stability of electronic states, which is crucial for numerous practical applications.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.11.013
      Issue No: Vol. 309 (2018)
       
  • Second metals (Lanthanum, Cerium, and Yttrium) modified W/SiO2 catalysts
           for metathesis of ethylene and 2-butene
    • Authors: Narongrat Poovarawan; Kongkiat Suriye; Joongjai Panpranot; Wimonrat Limsangkass; Adisak Guntida; Francisco José Cadete Santos Aires; Piyasan Praserthdam
      Pages: 43 - 50
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Narongrat Poovarawan, Kongkiat Suriye, Joongjai Panpranot, Wimonrat Limsangkass, Adisak Guntida, Francisco José Cadete Santos Aires, Piyasan Praserthdam
      Lanthanum, cerium, and yttrium were added as a second metal on the WO3/SiO2 catalysts by the incipient wetness impregnation method with the atomic ratio between the second metal and tungsten 0.083 in order to improve the catalytic performances of W-based catalysts in the metathesis of ethylene and 2-butene. As revealed by various characterization results from X-ray diffraction, nitrogen physisorption, inductively coupled plasma optical emission spectrometry, ion-exchange titration, FT-Raman, ammonia temperature programmed desorption (NH3-TPD), and reactant-TPD, the dispersion of tungsten and adsorption properties were significantly improved by adding of the second metals, especially the adsorption of the mixed cis/trans-2-butene isomers. Hence, their catalytic performances were higher than the non-modified one when mixed cis/trans-2 butene isomers were used as the feeds. In addition, the presence of La as the second metal could also reduce coke formation on the catalysts probably by decreasing the ensemble site effect.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.11.012
      Issue No: Vol. 309 (2018)
       
  • One-pot synthesis of benzimidazole using DMF as a multitasking reagent in
           presence CuFe2O4 as catalyst
    • Authors: Kalidas B. Rasal; Ganapati D. Yadav
      Pages: 51 - 60
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Kalidas B. Rasal, Ganapati D. Yadav
      One pot synthesis of benzimidazole from o-nitroaniline was achieved by using CuFe2O4 as a catalyst. It comprises the reduction of o-nitroaniline followed by cyclization, without using an external H2 source. The thermal decomposition of DMF in situ generates CO, which undergo water gas shift reaction (WGSR) in the presence of CuFe2O4 to produce hydrogen. It reduces −NO2 (nitroaniline) to −NH2 (o-phenylenediamine, OPD). The further cyclisation of OPD to benzimidazole was done by using DMF as a C1 source, in the presence of magnetically separable CuFe2O4 as catalyst. This is the first example of its kind being reported here. The catalyst was prepared by a simple hydrothermal method, with an environmentally benign starting material. CuFe2O4 is cheap and reusable having very low toxicity. This is an economical synthetic protocol for benzimidazole from o-nitroaniline with 100% conversion in 12h with 97.5% selectivity. A variety of o-nitroaniline substrates were studied using the protocol with excellent conversion and selectivity in each case.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.10.014
      Issue No: Vol. 309 (2018)
       
  • Mesoporous tin oxide: An efficient catalyst with versatile applications in
           acid and oxidation catalysis
    • Authors: Pandian Manjunathan; Vijaykumar S. Marakatti; Prakash Chandra; Atul B. Kulal; Shubhangi B. Umbarkar; Raman Ravishankar; Ganapati V. Shanbhag
      Pages: 61 - 76
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Pandian Manjunathan, Vijaykumar S. Marakatti, Prakash Chandra, Atul B. Kulal, Shubhangi B. Umbarkar, Raman Ravishankar, Ganapati V. Shanbhag
      Mesoporous tin oxide was prepared by template assisted and template-free methods. As-prepared materials were calcined at various temperatures to generate different nature (Brønsted and Lewis), amount and strength of acidic sites. The physico-chemical properties of the catalysts were studied by XRD, N2 sorption, pyridine-FTIR, NH3-TPD, DRS UV-vis, TGA, SEM, TEM, 1H MAS and 119Sn MAS NMR analyses. The catalytic behavior of mesoporous tin oxide catalysts was evaluated for acetalization and ketalization of glycerol with benzaldehyde and acetone respectively under solvent free conditions. The catalytic performance of mesoporous tin oxide was compared with that of other conventional solid acid catalysts namely H-ZSM-5, H-mordenite, H-beta, Al-MCM-41, Al-SBA-15 and Al-TUD-1. The efficiency of mesoporous tin oxide was also tested for cyclohexene epoxidation reaction. The catalyst prepared by template assisted method showed excellent catalytic performance compared to other catalysts due the difference in nature and amount of acidic sites in the catalyst. Meso-SnO2-T-350 was stable and reusable catalyst for four cycles without any appreciable loss in activity, and therefore it offers a good catalyst for potentially wide applications.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.10.009
      Issue No: Vol. 309 (2018)
       
  • A study of CO2 reforming of CH4 for coal delivered gases over Ni-based
           catalysts
    • Authors: Wahab O. Alabi; Hui Wang; Wei Huang; Xiaodong Li
      Pages: 77 - 82
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Wahab O. Alabi, Hui Wang, Wei Huang, Xiaodong Li
      NiCo-Mg/Al-1.7, Ni-Mg/Al-1.6, Ni-Mg/Al-0, and NiCo-Mg/Al-0.3 Ni-based catalysts were used to test their performance in CO2 reforming of CH4 reaction for a coal gas feed mainly containing CO and H2 as well as CO2 and CH4 at 900°C and the ambient pressure. Compared to the performance in ideal feed of CO2 and CH4 balanced with N2, the smaller reaction rate in the coal gas observed over all the catalysts was barely due to the lower concentration of CO2 and CH4 in the feed. NiCo-Mg/Al-1.7 catalyst showed the highest activity and stability among the four catalysts owing to its right metallic NiCo alloy sites to activate CH4 and the strong basic sites to activate CO2. The TPO of the spent catalyst after 24h TOS showed no carbon formation. The other three catalysts facilitated more or less various formats of carbon formation depending on different surface properties, leading to the decay of catalytic activity along the TOS. The coal gas feed that contains very small amount of O2 helped mitigate the formation of the inactive graphitic carbon, possibly because O2 burned the carbon of this kind. This study will improve the efficiency of using coal gas by converting its to-be-emitted CO2 and CH4 into valuable CO and H2.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.10.008
      Issue No: Vol. 309 (2018)
       
  • The effect of titration time on the catalytic performance of Cu/CeO2
           catalysts for water-gas shift reaction
    • Authors: Hyun-Suk Na; Jae-Oh Shim; Won-Jun Jang; Kyung-Won Jeon; Hak-Min Kim; Yeol-Lim Lee; Da-We Lee; Seong-Yeun Yoo; Jong Wook Bae; Chandrashekhar V. Rode; Hyun-Seog Roh
      Pages: 83 - 88
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Hyun-Suk Na, Jae-Oh Shim, Won-Jun Jang, Kyung-Won Jeon, Hak-Min Kim, Yeol-Lim Lee, Da-We Lee, Seong-Yeun Yoo, Jong Wook Bae, Chandrashekhar V. Rode, Hyun-Seog Roh
      We herein report the preparation of ceria (CeO2) via a simple precipitation method for use as a catalyst support in the water-gas shift (WGS) reaction. More specifically, we optimized the titration time required to obtain highly active CeO2-supported catalysts for the WGS reaction. As such, Cu was employed as the active metal coupled with the CeO2 support. Notably, the CeO2–0 supported Cu catalyst (where the precipitant was immediately injected into a cerium nitrate solution) exhibited the highest CO conversion at a gas hourly space velocity of 36,050h−1. This high catalytic activity of the Cu/CeO2–0 catalyst was mainly due to its high Brunauer-Emmett-Teller (BET) surface area, enhanced Cu dispersion, high number of oxygen vacancies, and enhanced reducibility.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.10.007
      Issue No: Vol. 309 (2018)
       
  • Sensitizing with short conjugated molecules: Multimodal anchoring on ZnO
           nanoparticles for enhanced electron transfer characteristics, stability
           and H2 evolution
    • Authors: Leena George; Subrahmanyam Sappati; Prasenjit Ghosh; R. Nandini Devi
      Pages: 89 - 97
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Leena George, Subrahmanyam Sappati, Prasenjit Ghosh, R. Nandini Devi
      Sensitizing semiconductors with organic dyes is usually employed to improve efficiency of semiconductors towards visible light absorption and charge transport. However, till date most of the dyes are either noble metal based with complex and expensive synthesis procedure or have a very narrow absorption band. Further the photostability of the dyes is another important issue. In this work we have studied, using a combination of photophysical and computational methods, ZnO nanoparticles sensitized with transition metal free, cheap and easy to synthesize azoquinoline dye that has been designed to have multiple chelating sites, viz., carboxylic group and hydroxyl imine group as a photocatalyst for water splitting activity. We find that the presence of multiple chelating sites facilitates dual mode of anchoring on ZnO nanoparticles, which leads to enhanced photostability and H2 generation of the composite. This is attributed to the incorporation of resonance features in the dye that increases electron transfer between ZnO and dye in contrast to the charge accumulation and photo degradation observed in non-conjugated and single site anchoring counterparts. Electron transfer from ZnO to dye under UV light and reverse in visible light could be identified experimentally. Such simple designing aspects can aid in identifying better catalysts for photocatalytic water splitting.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.09.052
      Issue No: Vol. 309 (2018)
       
  • Understanding interactions between lignin and ionic liquids with
           experimental and theoretical studies during catalytic depolymerisation
    • Authors: Sandip Kumar Singh; Subhrashis Banerjee; Kumar Vanka; Paresh Laxmikant Dhepe
      Pages: 98 - 108
      Abstract: Publication date: 1 July 2018
      Source:Catalysis Today, Volume 309
      Author(s): Sandip Kumar Singh, Subhrashis Banerjee, Kumar Vanka, Paresh Laxmikant Dhepe
      Compared to H2SO4, Brønsted acidic ionic liquid (BAIL, [C3SO3HMIM][HSO4]) catalyzed depolymerization of lignin yielded higher concentration of low molecular weight products under mild conditions (120°C) as proven by GC and GC–MS. To comprehend this disparity in catalytic activity among H2SO4 and BAIL (at similar H+ concentration), experimental techniques [1D(1H) NMR, 2D(15N/1H HMBC) NMR and RAMAN] have been employed. Based on these studies, it has been proven that the transfer of electron density from substrate to the electron deficient imidazolium ring via formation of hydrogen bond between OH/OCH3 (substrate) and N1C2H2 N3− (cation) is possible, while the anion plays an important role. Further, density functional theory (DFT) calculations also corroborated this fact by showing a change in the bond angle and decrease in bond length (C2 H2 in imidazole), due to the presence of weak and strong hydrogen bonding between the substrate and IL.
      Graphical abstract image

      PubDate: 2018-04-25T00:47:41Z
      DOI: 10.1016/j.cattod.2017.09.050
      Issue No: Vol. 309 (2018)
       
  • C1 Catalysis Symposium
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Kunlun Ding, James J. Spivey, Nitin Kumar, Zi Wang


      PubDate: 2018-05-31T15:36:49Z
       
  • A perspective on chromium-Free iron oxide-based catalysts for high
           temperature water-gas shift reaction
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Minghui Zhu, Israel E. Wachs
      Recent efforts to replace toxic hexavalent chromium oxide in commercial copper-chromium-iron oxide catalysts for the High-Temperature Water-Gas Shift (HT-WGS) reaction are reviewed. Advances in understanding the fundamentals of the HT-WGS reaction catalyzed by copper-chromium-iron oxide reveal that the role of chromium is to act as textural promoter to stabilize the surface area of the iron oxide phase towards sintering. The lack of in situ/operando spectroscopic characterization of the bulk and surface phases of the newly designed promoted catalysts, however, severely hampers a thorough understanding of the chemical states as well as the exact role of the non-Cr promoters. Future research studies will need to perform in situ/operando spectroscopy studies to fill this void to allow for the rational design of advanced HT-WGS catalysts.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Recent advances in the investigation of nanoeffects of Fischer-Tropsch
           catalysts
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Wen Chen, Tiejun Lin, Yuanyuan Dai, Yunlei An, Fei Yu, Liangshu Zhong, Shenggang Li, Yuhan Sun
      Fischer-Tropsch synthesis (FTS) is a structure-sensitive reaction for sustainable production of green fuels and value-added chemicals via syngas derived from coal, biomass, shale gas and natural gas. The nanostructure of a Fischer-Tropsch (FT) catalyst plays a crucial role in its catalytic performance. This review summarizes recent advances in the investigation of nanoeffects of FT catalysts, especially the effects of the active phase, particle size and exposed facet on catalytic performance. Perspectives and challenges for further research in nanocatalysis for syngas conversion are also given.

      PubDate: 2018-05-31T15:36:49Z
       
  • Recent progress in the photocatalytic reduction of aqueous carbon dioxide
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Baiyin Wang, Wei Chen, Yanfang Song, Guihua Li, Wei Wei, Jianhui Fang, Yuhan Sun
      Using solar energy to convert CO2 to value-added chemicals and fuels can not only reduce carbon emission by the utilization of CO2 as feedstock, but also store solar energy as high-energy-density fuels, being considered an ultimate strategy to solve environment and energy issues. Developing efficient photocatalysts and photocatalytic systems for CO2 reduction is the most essential part in achieving this goal. Considerable developments in CO2 photocatalytic reduction have been made over past decades. This article reviews the latest progresses in aqueous CO2 photoreduction related to photocatalytically experimental design and photocatalyst materials, including TiO2-based photocatalysts, metal oxide-based photocatalysts, sulfide-based photocatalysts, graphene-based photocatalysts, oxometallate-based photocatalysts and other photocatalysts. In addition, experimental and theoretical studies on the possible mechanisms of CO2 photo-reduction reaction as well as the potential methods for mechanisms studies are also summarized. On the basis of the aforementioned discussions, we present the future prospects for further development of CO2 photocatalytic reduction.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Chemical looping as a reactor concept for the oxidative coupling of
           methane over the MnxOy-Na2WO4/SiO2 catalyst, benefits and limitation
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Samira Parishan, Patrick Littlewood, Aleks Arinchtein, Vinzenz Fleischer, Reinhard Schomäcker
      The chemical looping concept (CLC) has been implemented to suppress the formation of COX in an oxidative coupling of methane (OCM) reactor under a wide range of conditions. In comparison to the normal co-feeding strategy, this technique resulted in an enhanced C2 selectivity at the same methane conversions. Nevertheless, the obtained yield never exceeded 25% which is still lower than the minimum value needed for industrializing OCM. The CLC was applied in mechanistic studies to investigate the consecutive reaction of the main products of OCM, i.e. ethane and ethene. The performance of the reaction of C2 components at 750°C in the chemical looping reactor was compared with that obtained in the co-feeding experiments. The effect of the surface adsorbed oxygen species on the reaction of both ethane and ethene was investigated. The results of these experiments reveal that some of the mechanistic assumptions about the OCM reaction are not compatible with the nature of MnxOy-Na2WO4/SiO2, one of the most stable and best performing catalysts known for this reaction. The yield limitation is shown to be inherent to the catalyst. However, this limitation should be solvable through the modified process concept aiming at the production of ethane in a separated first step.

      PubDate: 2018-05-31T15:36:49Z
       
  • Complete Oxidation of Methane on Co3O4/CeO2 Nanocomposite: A Synergic
           Effect
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Jian Dou, Yu Tang, Longhui Nie, Christopher M. Andolina, Xiaoyan Zhang, Stephen House, Yuting Li, Judith Yang, Franklin (Feng) Tao
      Development of nonprecious metal-based catalysts highly active for complete oxidation of CH4 at a temperature ≤600 °C is significant for removing unburned CH4 at exhaust of engines of vehicles using natural gas or liquefied petroleum gas. CeO2 is active for complete oxidation of CH4. Co3O4 has been identified as a promising catalyst for this reaction. A Co3O4/CeO2 nanocomposite catalyst consisting of ceria nanorods supported on Co3O4 nanoparticles was prepared through a modified deposition precipitation method. The Co3O4/CeO2 nanocomposite exhibits high activity for complete oxidation of methane with an apparent activation energy of 43.9 kJ/mol, which is obviously lower than 95.1 kJ/mol of pure CeO2 and 89.7 kJ/mol of pure Co3O4, suggesting a synergetic effect between Co3O4 and CeO2. Surface of the Co3O4/CeO2 nanocomposite during complete oxidation of CH4 in the temperature range of 200–500 °C and potential stable intermediate of this catalysis were identified with ambient pressure X-ray photoelectron spectroscopy (AP-XPS).

      PubDate: 2018-05-31T15:36:49Z
       
  • Higher alcohol synthesis via syngas over CoMn catalysts derived from
           hydrotalcite-like precursors
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Peiyi Liao, Chen Zhang, Lijun Zhang, Yanzhang Yang, Liangshu Zhong, Hui Wang, Yuhan Sun
      A series of CoMn catalysts derived from hydrotalcite precursors with different Co/Mn molar ratios were prepared and applied for higher alcohols synthesis (HAS) via syngas. The physical and chemical properties of as-prepared catalysts were investigated by various characterization methods such as BET, XRD, TPR, TG, SEM, HRTEM and EDS. The results showed that the proper Co/Mn molar ratio can increase the specific surface area, improve the reducibility, and form regular layered structure to provide more uniform distribution of active sites, thereby enhancing the catalytic activity and alcohol selectivity. When the Co/Mn ratio of catalyst reached 2, the highest space time yield (STY) and selectivity of alcohol were obtained. Moreover, the CoMn catalyst with layered structure showed higher activity and yield of alcohol under high reaction temperature than that without layered structure. Characterization results indicated that the layered structure catalyst can provide larger surface area, smaller particles size, and stronger interaction between Co and Mn, as well as resist the separation of Co, Mn and prevent the aggregation, thus improving the catalytic performance of CoMn catalysts for higher alcohols synthesis. In addition, the CoMn catalyst obtain derived from hydrotalcite precursors presented great stability for keeping active site highly disperse on the layer during the long reaction time.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Direct conversion of CO2 to long-chain hydrocarbon fuels over
           K–promoted CoCu/TiO2 catalysts
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Zhibiao Shi, Haiyan Yang, Peng Gao, Xiaopeng Li, Liangshu Zhong, Hui Wang, Hongjiang Liu, Wei Wei, Yuhan Sun
      A series of TiO2 supported Co–Cu catalysts with the weight percent of potassium oxides ranged from 0 to 3.5wt.% were synthesized. This work investigates the influence of potassium promoter on CO2 hydrogenation to long-chain (C5+) hydrocarbons. The introduction of suitable amount of K into the CoCu/TiO2 catalyst remarkably promoted the formation of C5+ hydrocarbons and suppressed methane formation. The temperature-program desorption measurements demonstrate that the addition of K increases the chemisorption of CO2, whereas H2 adsorption is decreased, which enhanced production of liquid fuels. However, these effects were not obvious with the addition of excess amount of K due to the slight change of surface K content. A maximum C5+ yield with CO2 conversion of 13% and C5+ selectivity of 35.1 C-mol% is obtained over the CoCu/TiO2 catalyst with 2.5wt.% of potassium promoter loading, which also exhibits a substantial stability.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Methanol steam reforming over Ni-CeO2 model and powder catalysts: Pathways
           to high stability and selectivity for H2/CO2 production
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Zongyuan Liu, Siyu Yao, Aaron Johnston-Peck, Wenqian Xu, José A. Rodriguez, Sanjaya D. Senanayake
      Nickel-ceria has been reported as a very good catalysts for the reforming of methane. Here, the methanol steam reforming reaction on both powder (Ni-CeO2) and model (Ni-CeO2-x(111)) catalysts was investigated. The active phase evolution and surface species transformation on powder catalysts were studied via in situ X-ray diffraction (XRD) and diffuse reflectance infrared transform spectroscopy (DRIFTS). Phase transitions of NiO → NiC → Ni and CeO2 → CeO2-x were observed during the reaction. The simultaneous production of H2/CO2 demonstrates that the active phase of the catalysts contains metallic Ni supported over partially reduced ceria. The DRIFTS experiments indicate that a methoxy to formate transition is associated with the reduction of ceria whereas the formation of carbonate species results from the presence of metallic Ni. A study of the reaction of methanol with Ni-CeO2-x(111) by X-ray photoelectron spectroscopy (XPS) points to the essential role of metal-support interactions in an oxygen transfer from ceria to Ni that contributes to the high selectivity of the catalysts.

      PubDate: 2018-05-31T15:36:49Z
       
  • Dimethyl ether carbonylation over pyridine-modified MOR: Enhanced
           stability influenced by acidity
    • Abstract: Publication date: 1 August 2018
      Source:Catalysis Today, Volume 311
      Author(s): Ying Li, Qi Sun, Shouying Huang, Zaizhe Cheng, Kai Cai, Jing Lv, Xinbin Ma
      The stability of MOR zeolite in DME carbonylation is a primary constraint in the industrialization of ethanol synthesis from syngas. Pyridine adsorption is recognized as an efficient technique to improve stability and as such, this study focuses on the influence of Brønsted acid density and strength on the stability of H-MOR saturated with pyridine in the DME carbonylation process. The acid properties of H-MOR catalysts was adjusted by a simple but efficient procedure. The methods employed to generate quantitative results of the acid properties include FTIR for the OH region, IR spectra for pyridine adsorption, as well as Pyr-TPD (to monitor the quantity and strength of acid sites). The results indicated that the concentration of Brønsted acid site strongly influences the stability of pyridine adsorption, which was further expounded by DFT calculations. In addition, the deactivation behavior of the catalyst with respect to Brønsted acid site strength in 12-MR channels was also explored by use of the DFT modelling method. It suggested that the coke intermediate formed in the 12-MR will lead to the desorption of neighboring adsorbed pyridine due to the steric effect, which contribute to an accelerated deactivation.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Ruthenium tris bipyridine derivatives and their photocatalytic activity in
           [4+2] cycloadditions. An experimental and DFT study
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Sergio S. Rozenel, Carlos R. Azpilcueta, Martha M. Flores-Leonar, Juan P.F. Rebolledo-Chávez, Luis Ortiz-Frade, Carlos Amador-Bedolla, Erika Martin
      We report the study of a series of Ru-bipyridine (Ru-Bpy) complexes to correlate their photophysical and electrochemical properties to their performance in [4+2] cycloadditions, as a model reaction for electron transfer catalysis. Redox potentials, absorption and emission spectra, quantum yields and DFT calculations are presented to understand the catalytic transformation. The study shows that complex [Ru(Bpy)3](PF6)2 is the more active photocatalyst, giving complete conversion to the product after 2h reaction under white light. Any substitution in the para position of the Bpy ring decreases the reaction conversion. The [4+2] cycloaddition can be performed with different substrates and dienes, using either acetonitrile or nitromethane as solvents. Mechanistic studies suggest that the active catalyst for the transformation is [Ru(Bpy)3]3+ and that the rate determining step is the oxidation of [Ru(Bpy)3]2+ to generate the corresponding Ru3+ species.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Synthesis of Sm3+-doped graphitic carbon nitride nanosheets for the
           photocatalytic degradation of organic pollutants under sunlight
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Jesty Thomas, Ambili K.S., Radhika S.
      Sm3+-doped g-C3N4 nanosheets with efficient solar photocatalytic activity were synthesized and their structural and optical properties were characterized. UV–vis diffuse reflectance spectral studies revealed that the absorption edge is red shifted in all Sm3+-doped samples and Sm3+-doping decreases the band gap of g-C3N4, thereby increases visible light absorption. The separation efficiency of the electrons and holes was obtained from PL spectral studies. The solar photocatalytic activity of the synthesized catalysts was assessed by studying the degradation of different dyes under sunlight. The synthesized photocatalyst was applied for the degradation of a synthetic dye effluent and an endocrine disrupting organic compound, salicylic acid under sunlight and showed more efficiency than the commercial photocatalyst, Degussa P-25. Studies revealed that hydroxyl radicals and holes play significant role in the degradation of dye effluent under sunlight. Further, the possible mechanism of the photocatalytic degradation of pollutants using Sm3+-doped graphitic carbon nitride is also proposed.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Silver-modified octahedral anatase particles as plasmonic photocatalyst
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Z. Wei, M. Janczarek, M. Endo, C. Colbeau-Justin, B. Ohtani, E. Kowalska
      Octahedral anatase particles (OAPs) were modified with silver nanoparticles (NPs) by photodeposition method. The properties of OAPs influenced the properties of silver deposits, and thus the photocatalytic activity of the obtained silver-modified OAPs. Photocatalytic activities were tested under UV and vis irradiation for oxidative decomposition of acetic acid and oxidation of 2-propanol, respectively. The properties of silver-modified OAPs were investigated by XRD, STEM, DRS, XPS and time-resolved microwave conductivity (TRMC) method. It was found that electron traps (ETs) worked as nucleation sites for silver, resulting in formation of smaller silver NPs on smaller OAPs with larger content of ETs. The modification with silver resulted in enhanced photocatalytic activity under both UV and vis irradiation. It was found that larger crystallite size of silver NPs, and thus larger polydispersity of silver deposits resulted in broad and intense plasmon resonance peak causing enhanced visible activity. The correlation between photocatalytic activity and TRMC data, e.g., slower decay of TRMC signal for more active samples, allowed discussion on property-governed photocatalytic activities of silver-modified titania.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Facile synthesis of carbon- and oxygen-rich graphitic carbon nitride with
           enhanced visible-light photocatalytic activity
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Donald K.L. Chan, Jimmy C. Yu
      A facile method has been developed for the preparation of g-C3N4 with increased specific surface area and visible light absorption. Carbon- and oxygen- rich graphitic carbon nitride (C,O-g-C3N4) were fabricated by heating thiourea with a small quantity of citric acid. The products were then exfoliated by thermal oxidation of C,O-g-C3N4 in air. Both specific surface area and optical absorption increased with the incorporation of carbon and oxygen. Exfoliated C,O-g-C3N4 exhibited significantly enhanced photocurrent and excellent photocatalytic performance in hydrogen evolution reaction under visible-light irradiation.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Titania versus zinc oxide nanoparticles on mesoporous silica supports as
           photocatalysts for removal of dyes from wastewater at neutral pH
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Darja Maučec, Andraž Šuligoj, Alenka Ristić, Goran Dražić, Albin Pintar, Nataša Novak Tušar
      For the photocatalytic wastewater treatment containing lower concentrations of dyes as pollutants, a suitable photocatalyst may be selected for anionic or cationic dye removal according to the photocatalyst surface charging and desired adsorption/degradation ratio. Herein, for the first time, we evaluate mesoporous silica supported TiO2 versus mesoporous silica supported ZnO photocatalysts at neutral pH and at equal conditions. The evaluation shows that model anionic dye Reactive Blue 19 (RB19) was adsorbed onto silica supported ZnO nanoparticles at neutral pH in a much higher rate than on silica supported TiO2 nanoparticles, even though the surfaces of ZnO and TiO2–silica composite catalysts were negatively charged in both cases (ca. −20mV of zeta potential). This was ascribed to the strong positive zeta potential of pure ZnO nanoparticles at neutral pH value (ca. +37mV) and consequently to more mixed oxide (spinel-like) ZnO/silica composite behaviour if compared to the physical mixture of oxide TiO2/silica composites. The highest dye adsorption (50%) and the fastest dye degradation (kapp =0.0544min−1 at 25°C) was observed on disordered ZnO/silica with Zn:Si molar ratio 1:1. Pure TiO2 or silica supported TiO2 nanoparticles were stable under UV irradiation. On the other hand, the interaction between SiO2 and ZnO resulted in increased resistance of ZnO to photocorrosion, which was proven to be an issue in pure ZnO nanoparticles.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Plasma-catalytic decomposition of nitrous oxide over
           γ-alumina-supported metal oxides
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Jin-Oh Jo, Quang Hung Trinh, Seong H. Kim, Young Sun Mok
      This work investigated the decomposition of dilute N2O from gas streams with various oxygen contents by using a plasma-catalytic process over metal oxide catalysts supported on γ-Al2O3. Among the metals explored (Ru, Co, Cu, V, etc.), Ru was found to be the best catalyst for the decomposition of N2O in a plasma-catalytic reactor, and most of the experiments were conducted with alumina-supported Ru. The effects of applied voltage, reaction temperature, O2 content, gas flow rate and initial N2O content on the decomposition efficiency and byproducts formation were examined. Compared to the catalyst-alone case, the presence of plasma enhanced the decomposition efficiency by 30–50%, depending on the operating condition. The increase in the oxygen content from 0 to 20% largely decreased the catalytic decomposition efficiency, whereas in the presence of plasma N2O could be successfully decomposed even at 20% O2 content. The decomposition efficiency was not a strong function of the initial N2O concentration in the range of 225–1800ppm, exhibiting pseudo first-order reaction kinetics. Without O2, there were negligible byproducts, but in the presence of O2, NO and NO2 were formed mainly due to the plasma-induced reactions between background molecules such as N2 and O2. The results obtained in this work showed the feasibility of plasma-catalytic process for the abatement of N2O.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Connecting contact angle evolution to photocatalytic kinetics of self
           cleaning surfaces
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): David Ollis
      We demonstrate that the Cassie-Baxter model of contact angle for a composite surface consisting of “bare” and “covered” components (typically adventitious or purposeful carbonaceous deposits) can be used for quantitative determination of the kinetics of “self-cleaning” photocatalyst surfaces. In particular, literature data is analyzed to demonstrate examples of zero and first order reaction, as well as quantitative determination of rate constant values for two key processes: the initial activation of new photocatalysts, and the removal of purposeful fatty acid deposits such as that required in the ISO standard 27448: 2009 for activity determination of photocatalytic self-cleaning surfaces.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Stable reduced Ni catalysts for xylose hydrogenation in aqueous medium
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Ruddy Morales, Cristian H. Campos, J.L.G. Fierro, Marco A. Fraga, Gina Pecchi
      Precursor materials with 20wt.% nickel content and formula mater Nd1-xCexAl0.162Ni0.838O3 (x=0.0, 0.1, 0.5, 0.7) were successfully used to prepare reduced Ni nanoclusters to be used as catalysts in the catalytic hydrogenation of xylose to xylitol. Reduction at 500°C led to large reduced nickel content with almost no changes in the structure of the started mixed oxide precursors. The catalytic performance of the Ni-reduced catalysts did not show a clear relation with Ce content while a close dependence of the hydrogenated products with Ni° crystal size and the isomerization product with acidity was obtained. The well-known Ni leaching in aqueous medium was absent in the prepared Ni-reduced catalysts corroborating the promising use of crystalline mixed oxides as precursors to prepare stabilized Ni-reduced catalysts for aqueous-phase processing of biomass-derived compounds.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Anatase TiO2 co-doped with silver and ceria for antibacterial application
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Benjawan Moongraksathum, Yu-Wen Chen
      Anatase TiO2 co–doped with Ag and CeO2 (Ag/CeO2–TiO2) was prepared by the peroxo sol-gel method for antibacterial application. The as-prepared materials were characterised by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The antibacterial activities of the samples were tested against two different bacteria: Escherichia coli (OP50), a Gram-negative organism and Staphylococcus aureus (USA300), a Gram-positive organism. The antibacterial effectiveness of the Ag/CeO2–TiO2 coating was >99.99%, i.e. it was extremely effective against both E. coli (OP50) and S. aureus (USA300) after either 30min of illumination with UVA radiation or 24-h of incubation in the dark. The Ag/CeO2–TiO2 coating was found to be significantly more active than pure TiO2 and TiO2 doped with CeO2 or Ag alone. Therefore, Ag/CeO2–TiO2 can be used as a coating material for the disinfection of both Gram-positive and Gram-negative bacteria.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Valorization of chloromethanes by hydrodechlorination with metallic
           catalysts
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Luisa María Gómez-Sainero, José Palomar, Salama Omar, Carlos Fernández, Jorge Bedia, Ariadna Álvarez-Montero, Juan José Rodriguez
      The performance of Pd, Pt, Rh and Ru based catalysts in the hydrodechlorination of chloromethanes to obtain ethane and ethylene was evaluated by means of computational analysis and hydrodechlorination experiments. A computational analysis using density functional theory (DFT) was developed to obtain preliminary insight on the potential catalytic mechanisms for the reactions involved using palladium, platinum, rhodium and ruthenium metallic clusters. Stable catalytic intermediates were obtained by quantum-chemical calculations in the hydrodechlorination of dichloromethane on Pd6 and Rh6 clusters, presenting CH2 and CH3 radicals and C2H4, C2H6 and CH4 products. On the contrary, it was not possible to obtain all these stable intermediates using Pt6 and Ru6 clusters. Theoretical analysis revealed lower desorption energies for ethane and ethylene products in Pd6 than in Rh6 clusters, what indicates a favorable selectivity of Pd-based catalyst for desired C2 products. Then, carbon supported catalysts containing these four metals were prepared and experimentally evaluated in the hydrodechlorination of dichloromethane (DCM) and trichloromethane (TCM) at low H2 excess and a reaction temperature range of 150–400°C. In agreement with computational results, in experimental tests, the Pd based catalyst showed the best performance for the hydrodechlorination of chloromethanes to obtain C2 products, followed by Rh, Ru and Pt have a poor performance, in special Pt based catalyst, which shows almost no selectivity to C2 products. This computational and experimental study emphasizes, for the first time, the good performance (high activity and selectivity) of Pd carbon supported catalysts in the valorization of chloromethane compounds to obtain C2 hydrocarbon products.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • New solid oxo-rhenium and oxo-molybdenum catalysts for the
           deoxydehydration of glycols to olefins
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Bryan E. Sharkey, Alana L. Denning, Friederike C. Jentoft, Raju Gangadhara, Tirupathi V. Gopaladasu, Kenneth M. Nicholas
      Several new solid oxo-rhenium and oxo-molybdenum catalysts were tested for the deoxydehydration (DODH) of 1,2-diols to terminal olefins employing aromatic solvents and reaction temperatures of 150–200°C. A catecholato oxo-rhenium catalyst tethered to silica was prepared and found to have comparably high DODH activity to its soluble analog with triphenylphosphine as the reductant. Catalyst re-use and leach-test experiments show significant leaching into the liquid phase. Silica, ceria and, for the first time, alumina and iron oxide were tested as supports for perrhenate, with ceria producing the least active material in 1,2-decane diol DODH. Decene yields obtained with ReOx/SiO2, ReOx/Fe2O3, ReOx/Al2O3 were highest when triphenylphosphine was the reductant and reached 70−78% (at 90–100% conversion) at 150°C. These three catalysts were also effective with gaseous reductants H2 or CO. Leaching of rhenium species occurred for all supports and was most pronounced for SiO2. New solid oxo-molybdenum catalysts were synthesized. At 200°C, decene yields observed using MoOx/Fe2O3, MoOx/SiO2, MoOx/Al2O3, MoOx/TiO2 and MoOx/ZrO2 were comparable and did not exceed 20%. There were homogeneous contributions through leached molybdenum species.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Upgrading of stranded gas via non-oxidative conversion processes
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Hui Chen, Lili Li, Jianli Hu
      Ethane aromatization was carried out using metal promoted ZSM-5 catalysts. Desired products including ethylene and aromatics were obtained over Pt and Mo promoted ZSM-5 zeolite under reaction conditions of 600°C, 0.1MPa and GHSV=1000h−1. Results indicated that aromatics were formed via ethylene intermediate. Although ethane conversion and selectivity to aromatics were influenced by metal promoters, the distribution of benzene, toluene, xylenes and C9 aromatics depends mainly on the shape selective property of the ZSM-5. Ethane aromatization catalyst deactivated over time due to carbon deposition and metal leaching. Although oxidative regeneration could recovered 90% activity, the catalyst deactivated even faster after regeneration. For the purpose of economic comparison between direct and indirect natural gas conversion, the performance of edge coated Co-Re/γ-Al2O3 Fischer-Tropsch synthesis catalyst was presented. Even with capital savings on downstream refining, indirect natural gas conversion shows lower internal rate of return (IRR), largely because of higher capital and operating costs in syngas production.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Metal-based nanoparticles dispersed in glycerol: An efficient approach for
           catalysis
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Isabelle Favier, Daniel Pla, Montserrat Gómez
      The present mini-review describes the use of glycerol as solvent for the synthesis of metal and metal oxide nanoparticles exhibiting catalytic properties. This contribution specially underlines the ability of glycerol to both disperse and immobilize metal-based nanoparticles, increasing their lifetime. In other words, glycerol can act as a liquid support for nanocatalysts.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Regeneration study of Ni/hydroxyapatite spent catalyst from dry reforming
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Bruna Rego de Vasconcelos, Doan Pham Minh, P. Sharrock, A. Nzihou
      In the present work, the regeneration of a spent nickel hydroxyapatite-based catalyst (Ni/Ca-HA1_S) used in dry reforming of methane (DRM) was investigated. Three successive cycles of DRM/regeneration were performed. Two different gasifying agents were tested for the regeneration step: air and carbon dioxide (21%CO2/N2). The aim was to evaluate the ability of regeneration of the catalyst under different atmospheres. The regeneration was performed in situ at 700°C under 70mL/min of gasifying agent. Reproducible results were obtained between each cycle for the two atmospheres tested and only a small irreversible deactivation was noticed. Several characterizations (SEM, TEM, TPR, XRD) of the fresh and spent catalysts allowed proving that the irreversible deactivation was provoked by densification of nickel particles and core-shell carbon formation. Despite the slight decrease in reactants’ conversions, selectivity to syngas was around 80–90% during the three cycles of DRM/regeneration with both atmospheres and no changes in the selectivity were observed. The results proved that the Ni/Ca-HA1_S catalyst could be easily regenerated under different atmospheres and make it competitive for dry reforming of methane.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Study of cobalt molybdenum oxide supported on mesoporous silica for liquid
           phase cyclohexane oxidation
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Ashish P. Unnarkat, Tam Sridhar, Huanting Wang, Sanjay M. Mahajani, Akkihebbal K. Suresh
      Liquid phase oxidation of cyclohexane, by molecular oxygen, has been carried out using cobalt molybdenum oxide (CoMoO4) catalyst supported on mesoporous silica supports (SBA-15, KIT-6 and FDU-12). For each support, the catalyst activity has been studied as a function of loading, pore size, and calcination temperature. The catalysts were characterized using surface area analysis (BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Among the three supported catalysts, the one on FDU-12 shows the highest activity. The catalysts with lower loading, lower calcination temperature and lower pore size of support show higher activity but with lower selectivity. All the studied catalysts gave about 7–8% conversion, with selectivity of 85% for cyclohexanone and cyclohexanol (KA oil), before deactivation took over. The deactivated catalysts could be fully regenerated by re-calcination in every case. With such regeneration between runs, the catalysts are shown to retain their activity and selectivity over multiple cycles. The kinetic model which was proposed for the unsupported catalyst has been shown to work well for the supported catalysts as well.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Heterogeneously degradation of aniline in aqueous solution using
           persulfate catalyzed by magnetic BiFeO3 nanoparticles
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Imtyaz Hussain, Yongqing Zhang, Mingyu Li, Shaobin Huang, Waseem Hayat, Liangming He, Xiaodong Du, Guoqiang Liu, Meimei Du
      In this study, magnetic BiFeO3 nanoparticles (BFO MNPs) were successfully synthesized by simple sole-gel method. The BFO MNPs catalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) techniques. The prepared catalyst was used to activate persulfate (PS) to generate sulfate radicals (SO4 −) for the enhanced degradation of aniline from aqueous solution. It was found that BFO MNPs showed high catalytic activity toward PS decomposition for the degradation of aniline. The degradation efficiency of aniline (0.5 mM) was 100% within 120 min using initial dosage of 0.5 g/L BFO MNPs and concentration of 5 mM persulfate. Even at neutral pH (7.0), aniline was efficiently degraded in BFO MNPs /PS system. The effects of reaction parameters such as initial pH, PS concentration and dosage of BFO MNPs were investigated. The radical scavenging and electron paramagnetic resonance (EPR) results showed that sulfate radicals (SO4 −) and hydroxyl radicals (OH) were generated by the activation of PS with BFO MNPs for the degradation of aniline. The stability of catalyst was tested by means of successive reuse cycles. The results revealed that BiFeO3 catalyst exhibited high reusability and stability in degrading aniline through PS activation.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Preparation of alkylate gasoline in polyether-based acidic ionic liquids
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Feng-Li Yu, Gui-Xiao Li, Yu-Long Gu, Cong-Xia Xie, Bing Yuan, Shi-Tao Yu
      A series of novel polyether-based Brønsted acidic ionic liquids (ILs) have been synthesized, which contain both a polyoxyethylene (POE) chain and a sulfonic group (SO3H). The prepared ILs can well dissolve trifluoromethanesulfonic acid (TfOH), and IL/TfOH mixture has good intermiscibility with the reactants of isobutane and isobutene. Then, a new IL/TfOH catalytic system for the preparation of alkylate gasoline has been developed. The advantages of the new catalytic system are high selectivity for C8-alkylate product and the recyclability of TfOH catalyst. Under the optimal catalytic conditions (using the IL with the polymerization degree n=75, IL/TfOH(v/v)=5, reaction temperature 60°C, reaction time 30min, and stirring rate 800rpm), the C8-selectivity can reach 80%, and above 95% of C8-alkylate product is trimethylpentane (TMP). Therefore, the new IL/TfOH catalytic system can afford high-quality alkylate gasoline. In addition, the conversion of isobutene and C8-selectivity both have gradually a little drop during 6 recycles, which should attribute to a little loss of TfOH in every recycle.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Evaluation of the performance of α-alumina nano-porous ceramic composite
           membrane for esterification applications in petroleum refinery
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Edidiong Okon, Habiba Shehu, Edward Gobina
      The carrier gas permeation performance through α-alumina nano-porous ceramic membrane was investigated in this study. The four carrier gases used for the study were argon (Ar), helium (He), nitrogen (N2) and carbon dioxide (CO2). The experiments was carried out at the gauge pressure drop of 0.10–1.00bar at 80°C. The α-alumina membrane was prepared using the sol-gel dip-coating techniques. The dip-coated membrane exhibited a higher molar flux with He (0.046molm−2s−1) and Ar (0.037molm−2s−1) with a much lower flux for N2 (0.037molm−2s−1) and CO2 (0.035molm−2s−1) at 0.30bar. The membrane recorded a huge decrease of permeance with the four carrier gases in the range of 9.81783E-07molm−2 s−1 Pa−1 to 1.23237E-06molm−2 s−1 Pa−1 at 0.50bar. The gas flow rate increased with respect to the pressure drop across the membrane. A plot of the inverse square root of the gases molecular weight showed a linear dependence on the gas permeance. The order of the gas flow rate with respect to the mean pressure was He>Ar>CO2 >N2. The membrane was characterised using different methods including liquid nitrogen physisorption (Quantachrome instrument 2013) and scanning electron microscopy (Zeiss EVO LS10 SEM). The liquid nitrogen adsorption isotherm were described using the BET and BJH methods The BET surface area of the 7th dip-coated membrane was found to be higher (5.991m2/g) in contrast to the 8th dipped (3.840m2/g). The BJH pore size distribution of the membrane show a reduction pore size after the modification process. The BET isotherms of the membrane indicated a type IV isotherm with hysteresis on the curve indicating that the membrane can undergo a capillary condensation in the mesoporous region. The SEM/EDAX of support showed a clear surface without evidence of crack while the SEM micrograph of the silica membrane exhibit a bonding on the surface membrane as result of the modification process.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Electrocatalytic performance and carbon tolerance of ternary Au-Mo-Ni/GDC
           SOFC anodes under CH4-rich Internal Steam Reforming conditions
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Ch. Neofytidis, V. Dracopoulos, S.G. Neophytides, D.K. Niakolas
      The present work examines the effect of Au-Mo modification on the electrocatalytic performance and carbon tolerance of Ni/GDC for the internal CH4 steam reforming reaction. Comparative electrocatalytic measurements are presented between cells that comprise Ni/GDC and 3Au-3Mo-Ni/GDC as anodes under CH4-rich feed (S/C=0.3), without dilution in a carrier gas. Complementary electrochemical and physicochemical characterization was performed to investigate the possible modifications on the electrochemical and structural properties of the electrodes. In brief, the cell with Ni/GDC was more active catalytically, but exhibited worst electrocatalytic performance and operated for significantly shorter period with a degradation rate 5.5mV/h. The main degradation factor was the higher carbon formation rate, which increased gradually and affected the polarization resistance of the electrode. The cell with 3Au-3Mo-Ni/GDC was moderately active catalytically, but performed better and lasted for the double operating period with a degradation rate 2.6mV/h. In the latter case the carbon formation rate was almost negligible and degradation was attributed to the gradual re-oxidation of nickel, which affected the ohmic resistance of the electrode.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Mesoporous carbon aerogel supported PtCu bimetallic nanoparticles via
           supercritical deposition and their dealloying and electrocatalytic
           behaviour
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Sansim Bengisu Barim, Selmi Erim Bozbag, Haibo Yu, Rıza Kızılel, Mark Aindow, Can Erkey
      Mesoporous carbon aerogel (CA) supported PtCu bimetallic nanoparticles were prepared via a sequential supercritical deposition (SCD) method using supercritical carbon dioxide (scCO2). The effects of deposition order of the metal, annealing temperature and metal composition on the average PtCu particle size, size distribution and dispersion were investigated. Four sets of PtCu/CA samples were prepared with two Pt:Cu molar ratios (1:1 and 1:3) and with two different deposition orders (i.e. either Pt or Cu first). X-ray diffraction and electron microscopy data showed that all of the as-prepared samples formed homogeneously distributed disordered PtCu alloy nanoparticles with narrow particle size distributions on the CA support. Increasing annealing temperature in the range 600–950°C increased the average particle size from 1.8nm to 4.5nm and resulted in the elimination of separate Cu nanoparticles on the CA surface. The dealloying of the supported PtCu nanoparticles were carried out by cyclic voltammetry and the activity of the dealloyed nanoparticles (after 300 potential cycles) towards the oxygen reduction reaction (ORR) was investigated using rotating disc electrode (RDE) experiments. During dealloying, peaks associated with bulk dissolution and deposition of Cu and dissolution and re-deposition of Cu from the alloyed PtCu nanoparticles were observed at initial cycles along with peaks associated with creation of new Pt sites. Supported nanoparticles with Pt:Cu molar ratios of 1:1 and 1:3 which were prepared by deposition of Cu first had low activities towards ORR after dealloying. On the contrary, nanoparticles prepared by depositing Pt first exhibited promising electrocatalytic activities after dealloying. Samples with a Pt:Cu molar ratio of 1:3 showed higher activities than those with a molar ratio of 1:1. An enhanced ESA of 137m2/g and dealloying induced enhanced mass activity of 0.123A/mgPt was obtained using the sample with a Pt:Cu molar ratio of 1:3, which was annealed at 800°C. On the other hand, the same sample annealed at 950°C had the highest specific activity of 0.165mA/cm2.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • 3D characterization of gas phase reactors with regularly and irregularly
           structured monolithic catalysts by NMR imaging and modeling
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Jürgen Ulpts, Lars Kiewidt, Wolfgang Dreher, Jorg Thöming
      A heterogeneously catalyzed gas phase reaction process was characterized regarding temperature and concentration profiles by means of three dimensional (3D) 1H magnetic resonance spectroscopic imaging (MRSI), using the exothermal ethylene hydrogenation as an example. Here, temperature mapping was achieved by using specifically designed thermometers filled with ethylene glycol. The impact of heat and mass transfer on the process performance was investigated by using two different monolithic catalysts with completely different heat and mass transfer characteristics: a regularly structured honeycomb monolith and a irregularly structured open-cell foam packing. The influence of these characteristics on the reaction zones within the monolithic catalysts was demonstrated by simulations that were based on 2D reactor models. To evaluate the applicability of temperature and concentration mapping by 1H MRSI for model validation, a predictive two dimensional model of the process was applied. The resulting simulations of temperature profiles and concentration distributions were in very good agreement with the experimental data with deviations below 9%. Conventional mass spectroscopic measurements provided further evidence of the accuracy of 3D MRSI measurements as well as the 2D reactor model.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Design and operation of an ammonia-fueled microchannel reactor for
           autothermal hydrogen production
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Steven Chiuta, Dmitri G. Bessarabov
      The present work describes the design and operation of an autothermal microchannel reactor for portable and distributed hydrogen production via ammonia decomposition. The microreactor consists of an array of alternating catalytic plate channels where the heat for the endothermic ammonia decomposition reaction is supplied in adjacent microchannels via exothermic oxy-fuel combustion of ammonia. The reactor performance was investigated under various operating conditions, such as ammonia flow rate in the decomposition channel, combustible feed flow rate, and fuel equivalence ratios. The best operating conditions were obtained at ammonia flow rate of 0.4 NLPM, combustible feed flow rate of 0.8 NLPM, and fuel-rich operation corresponding to fuel equivalence ratio of 1.2. At these conditions, >99% NH3 conversion was obtained, and the reactor could generate enough hydrogen for a 45We fuel cell system at an equivalent reactor power density of 1.5kWe/L. Overall, the work reported here successfully demonstrated the feasibility of ammonia decomposition for distributed hydrogen generation and delineated the attainable operating region, results of which could be used further to advance and scale-up autothermal ammonia-fueled microchannel reactors in the kW-range.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
  • Superior catalytic performance of Mn-Mullite over Mn-Perovskite for NO
           oxidation
    • Abstract: Publication date: 15 July 2018
      Source:Catalysis Today, Volume 310
      Author(s): Sampreetha Thampy, Yongping Zheng, Sean Dillon, Chengfa Liu, Yasser Jangjou, Yun-Ju Lee, William S. Epling, Ka Xiong, Yves J. Chabal, Kyeongjae Cho, Julia W.P. Hsu
      The effects of complex-oxide crystalline phase on catalytic activity and the pathways of NO oxidation are investigated by comparing SmMn2O5 mullite and SmMnO3 perovskite crystals. Synthesized under the same conditions, SmMn2O5 shows activity at lower temperature (200°C) with a higher maximum conversion efficiency compared to SmMnO3 (52% vs. 36%), inspite of similar active site density. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results show nitrates as the primary surface reaction species. FTIR, XPS, and temperature programmed desorption (TPD) measurements all indicate that nitrate species are less stable on SmMn2O5 (<250°C) compared to SmMnO3 (>300°C). Results from density functional theory calculations show that the barrier for nitrate dissociation is much higher on the Sm-terminated (001) surface of SmMnO3. Combined experimental and theoretical findings suggest that the superior catalytic performance of SmMn2O5 mullite arises from the ability to regenerate its active sites with nitrate dissociation at lower temperatures for subsequent NO oxidation reactions.
      Graphical abstract image

      PubDate: 2018-05-31T15:36:49Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.198.158.24
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-