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  Subjects -> ENGINEERING (Total: 2410 journals)
    - CHEMICAL ENGINEERING (206 journals)
    - CIVIL ENGINEERING (201 journals)
    - ELECTRICAL ENGINEERING (112 journals)
    - ENGINEERING (1268 journals)
    - ENGINEERING MECHANICS AND MATERIALS (392 journals)
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    - MECHANICAL ENGINEERING (96 journals)

ENGINEERING (1268 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     Hybrid Journal   (Followers: 280)
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: 3)
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)
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: 14)
Advances in Polymer Science     Hybrid Journal   (Followers: 44)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 45)
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: 11)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 24)
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 3)
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)
Arab Journal of Basic and Applied Sciences     Open Access  
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: 9)
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     Hybrid Journal   (Followers: 1)
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)
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Open Access   (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: 43)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Thermal Engineering     Open Access   (Followers: 6)
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     Hybrid Journal   (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: 3)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 15)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Information Science and Management Engineering     Open Access   (Followers: 4)
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: 286)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 218)
Composites Part B : Engineering     Hybrid Journal   (Followers: 253)
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: 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: 34)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)

        1 2 3 4 5 6 7 | Last

Journal Cover
Applied Catalysis B: Environmental
Journal Prestige (SJR): 3.152
Citation Impact (citeScore): 11
Number of Followers: 18  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0926-3373
Published by Elsevier Homepage  [3159 journals]
  • Contrasting transient photocurrent characteristics for thin films of
           vacuum-doped “grey” TiO2 and “grey” Nb2O5
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Moisés A. de Araújo, Murilo F. Gromboni, Frank Marken, Stephen C. Parker, Laurence M. Peter, Josh Turner, Helen C. Aspinall, Kate Black, Lucia H. Mascaro Photo-catalytic performance for oxide films, here for inkjet-printed TiO2 (ca. 1 μm thickness on FTO) and for spray-pyrolysis-coated Nb2O5 (ca. 1 μm thickness on FTO), is affected by oxygen vacancies that form during vacuum-heat treatment at 550 °C. The effects of the oxygen vacancies are associated with formation of Ti(III) and Nb(IV) sites, respectively, and therefore optically visible as “grey” coloration. Photo-electrochemical light-on-off transient experiments are performed in the limit of thin film photoanodes, where front and back illumination result in the same photo-current responses (i.e. with negligible effects from internal light absorption gradients). It is shown that generally the magnitude of photo-currents correlates linearly with light intensity, which is indicative of dominant “photo-capacitive” behaviour. At an applied voltage of 0.4 V vs. SCE (in the plateau region of the photo-current responses) the potential and also the pH (going from 1.0 M KOH to 0.1 M HClO4 in the presence of methanol quencher) have no significant effect on photo-currents; that is, surface chemical/kinetic effects appear to be unimportant and interfacial hole transfer may be rate limiting. Under these conditions (and based on a simplistic mechanistic model) changes in photo-currents introduced by oxygen vacancy doping (detrimental for TiO2 and beneficial for Nb2O5) are assigned primarily to changes in electron mobility.Graphical abstractGraphical abstract for this article
       
  • N-CQDs accelerating surface charge transfer of Bi4O5I2 hollow nanotubes
           with broad spectrum photocatalytic activity
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Mengxia Ji, Yiling Liu, Jun Di, Rong Chen, Zhigang Chen, Jiexiang Xia, Huaming Li Novel N-doped carbon quantum dots (N-CQDs) modified Bi4O5I2 hollow nanotubes photocatalysts have been prepared for the first time. Bi4O5I2 nanomaterials with hollow nanotube structure were designed to shorten the charge carriers’ migration distance from bulk phase to surface while the N-CQDs was modified to accelerate the surface charge transfer. Multiple characterization methods have been applied to explore the phase structure, elemental composition, optical absorption properties and photocatalytic performance of as-prepared N-CQDs/Bi4O5I2 composites. The N-CQDs/Bi4O5I2-0.2 composite showed higher photocatalytic activity for the removal of bisphenol A than pure Bi4O5I2 hollow nanotube under UV light, visible light, light above 580 nm, which exhibited the broad spectrum photocatalytic activity. ESR analysis demonstrated the N-CQDs modification can tune the concentration of reactive oxygen species (•OH and •O2−). Combined with free radical trapping experiment results, hole, •OH and •O2− were demonstrated to be the main active species and synergistically promoted the enhancement of photocatalytic activity for N-CQDs/Bi4O5I2 composite.Graphical abstractA novel N-doped carbon quantum dots (N-CQDs) modified Bi4O5I2 hollow nanotubes photocatalyst was prepared for the first time. The N-CQDs/Bi4O5I2 composite showed higher photocatalytic activity for the removal of BPA than pure Bi4O5I2 hollow nanotube under UV light, visible light, light above 580 nm, which exhibited the broad spectrum photocatalytic activity.Graphical abstract for this article
       
  • Nanoceria supported rhodium(0) nanoparticles as catalyst for hydrogen
           generation from methanolysis of ammonia borane
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Derya Özhava, Saim Özkar This work reports the preparation and catalytic use of nanoceria supported rhodium(0) nanoparticles, Rh(0)/nanoCeO2, as catalyst for hydrogen generation from the methanolysis of ammonia borane. Rh(0)/nanoCeO2 was in situ formed from the reduction of rhodium(II) octanoate on the surface of nanoceria during the catalytic methanolysis of ammonia borane at room temperature. The results of analysis using PXRD, TEM, STEM-EDS, XPS, SEM, SEM-EDX, N2 adsorption-desorption and ICP-OES reveal that rhodium(0) nanoparticles were well dispersed on the surface of nanoceria with an average size of 3.9 ± 0.6 nm. Rh(0)/nanoCeO2 shows high catalytic activity in the methanolysis of ammonia borane with a turnover frequency of 144 min−1. Note that hydrogen generation from the methanolysis of ammonia borane catalyzed by Rh(0)/nanoCeO2 is slightly less than 3.0 equivalent, due to the reduction of Ce4+ ions to Ce3+ ions on the surface of nanoceria during the methanolysis of ammonia borane. The reduction of Ce4+ ions leading to the formation of Ce3+ defects on the surface of nanoceria under the catalytic reaction conditions could be investigated by high resolution Ce 3d XPS analysis. Additionally, the formation kinetic of rhodium(0) nanoparticles could be studied by using the hydrogen generation from the methanolysis of ammonia borane as reporter reaction; thus, the rate constants for the slow nucleation, k1 and autocatalytic surface growth of rhodium(0) nanoparticles, k2 were determined. Our report also includes the results of kinetic study of the catalytic methanolysis of ammonia borane depending on rhodium concentration and temperature.Graphical abstractGraphical abstract for this article
       
  • Highly active subnanometer Rh clusters derived from Rh-doped SrTiO3 for
           CO2 reduction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Binhang Yan, Qiyuan Wu, Jiajie Cen, Janis Timoshenko, Anatoly I. Frenkel, Dong Su, Xianyin Chen, John B. Parise, Eric Stach, Alexander Orlov, Jingguang G. Chen Sub-nanometer Rh clusters derived from Rh-doped SrTiO3, demonstrated by in-situ X-ray Diffraction (XRD) and X-ray Absorption Fine Structure (XAFS) measurements, are applied as highly active catalysts for CO2 reduction. Compared to the supported Rh/SrTiO3, the catalyst synthesized by a doping-segregation method exhibits a higher space-time yield (STY) to CO with a selectivity of 95% for CO2 reduction by hydrogen; it also shows a higher activity with a larger turnover frequency (TOF) for CO2 reduction by ethane. According to the in-situ diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) experiments, the higher CO selectivity for CO2 hydrogenation is attributed to the lower CO binding strength resulted by the strong interactions (e.g., charge transfer) between Rh atoms and the oxide support with surface defects. The superior activity is suggested to be originated from the cooperative effect between the highly dispersed sub-nanometer Rh clusters for efficient dissociation of H2/C2H6 and the reconstructed SrTiO3 with oxygen vacancies for preferential adsorption/activation of CO2. The doping-segregation method provides a unique opportunity to tune the size of active metal clusters and the physicochemical properties of the oxide support, offering the potential for applications in a variety of chemical reactions.Graphical abstractGraphical abstract for this article
       
  • Impact of structural defects and hydronium ion concentration on the
           stability of zeolite BEA in aqueous phase
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Sebastian Prodinger, Hui Shi, Huamin Wang, Miroslaw A. Derewinski, Johannes A. Lercher The presence of fluoride anions in the synthesis gel leads to zeolite BEA with high hydrothermal stability. This longer lifetime is caused by a lower concentration of internal silanol defects that are sites of the initial framework hydrolysis eventually destroying the lattice structure. The lifetime of these zeolites was the higher the lower the concentration of framework bridging hydroxyl groups that form hydronium ions was. While lattice hydrolysis was initiated at defect sites in all cases, the role of defects became less important as the concentration of hydronium ions increased. At higher concentration of hydrated hydronium ions, the presence of water associated with the hydrated hydronium ions limits the useful lifetime of zeolite catalysts in water. For such materials, the selective hydrophobization of the external surface extends the lifetime.Graphical abstractGraphical abstract for this article
       
  • CO/H2 adsorption on a Ru/Al2O3 model catalyst for Fischer Trospch: Effect
           of water concentration on the surface species
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): E. Jiménez-Barrera, P. Bazin, C. Lopez-Cartes, F. Romero-Sarria, M. Daturi, J.A. Odriozola Water presence and concentration strongly influence CO conversion and C5+ selectivity in the Fischer Tropsch reaction. In this work, the influence of the water concentration was investigated using a model Ru/Al2O3 (5 wt.%) catalyst. The surface species formed after CO and H2 adsorption in dry and wet (different water concentrations) conditions were analyzed by FTIR. Firstly, water adsorption was carried out up to complete filling of the pores and then CO was put in contact with the catalyst. The absence of adsorbed CO species in these conditions evidences that CO diffusion in water controls the access of the gas to the active sites and explains the negative effect of high water concentrations reported by some authors. Moreover, the adsorption of a mixture of CO+H2+H2O, being the water concentration close to that needed to have a monolayer, and a dry mixture of CO+H2 were carried out and compared. Results evidence that water in this low concentration, is able to gasify the surface carbon species formed by CO dissociation on the metallic sites. This cleaning effect is related to the positive effect of water on CO conversion detected by some authors.Graphical abstractWater concentration strongly influences the surface species on a model catalyst for the Fischer Tropsch reaction.Graphical abstract for this article
       
  • Peroxymonosulfate-enhanced visible light photocatalytic degradation of
           bisphenol A by perylene imide-modified g-C3N4
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Juanjuan Zhang, Xu Zhao, Yanbin Wang, Yan Gong, Di Cao, Meng Qiao In this study, a metal-free photocatalyst (PI-g-C3N4) was synthesized through an amidation reaction between perylene tetracarboxylic dianhydride (PTCDA) and graphitic carbon nitride (g-C3N4). In order to enhance the photocatalytic degradation efficiency of bisphenol A (BPA) by 5 wt% PI-g-C3N4, peroxymonosulfate (PMS) was introduced into this system. When 5 mM PMS was added, 96% of BPA with an initial concentration of 10 mg/L was degraded within 60 min; the pseudo-first-order degradation kinetics constant of BPA was increased from 0.0057 to 0.0501 min−1. Based on the photoelectrochemical analysis, it was proposed that PI-g-C3N4 achieved a more effective separation of photogenerated electron–hole pairs and displayed higher conductivity than PTCDA and g-C3N4 individually, thus promoting the PMS activation into active radicals by the photogenerated electrons. The BPA degradation was favored at high PMS concentrations under alkaline conditions. The slight inhibition effect of co-existing anions on the degradation of BPA followed the order: H2PO4−> NO3− ≈ HCO3−; Cl− had a remarkable positive effect on the degradation of BPA. The radical quenching tests and electron spin resonance results indicated that O2−, 1O2, and h+ were the major species for the degradation of BPA. Combined with intermediates analysis, the degradation mechanism and pathway of BPA was proposed. The high stability of the 5 wt% PI-g-C3N4 was finally demonstrated.Graphical abstractGraphical abstract for this article
       
  • Photodeposition of Pd nanoparticles on ZnIn2S4 for efficient alkylation of
           amines and ketones’ α-H with alcohols under visible light
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Bingqing Wang, Zirong Deng, Xianzhi Fu, Chao Xu, Zhaohui Li Pd nanoparticles with a small size of ca. 6 nm were deposited on the surface of ZnIn2S4 via photoreduction of Pd(CH3CN)2Cl2 over ZnIn2S4 under visible light. The resultant Pd-ZnIn2S4 nanocomposites were fully characterized and their catalytic performance for light induced N-alkylation of amines and α-H alkylation of ketones with alcohols were investigated. It was found that Pd-ZnIn2S4 nanocomposites show superior catalytic activity for the alkylation reactions via a successful coupling of the photocatalytic dehydrogenation of alcohols over ZnIn2S4 with Pd-based hydrogenation. An optimum performance was realized over 0.5 wt% Pd-ZnIn2S4 nanocomposites by synchronization of the rates of different reaction steps in the tandem alkylation reaction. Ascribed to the small sized Pd nanoparticles, which provide more active unsaturated Pd atoms, Pd-ZnIn2S4 nanocomposites obtained via photoreduction show superior performance as compared to Pd/ZnIn2S4 obtained via a chemical reduction using NaBH4. This study provides an efficient way to realize a highly efficient and stable alkylation of amines and α-H of ketones with alcohols under visible light. This study also highlights the great potential of construction of multifunctional catalysts for light induced organic syntheses.Graphical abstractGraphical abstract for this article
       
  • Promotion of catalytic selectivity on transition metal oxide through
           restructuring surface lattice
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Juanjuan Liu, Victor Fung, Yong Wang, Kaimin Du, Shiran Zhang, Luan Nguyen, Yu Tang, Jie Fan, De-en Jiang, Franklin Feng Tao Pursuit of high catalytic selectivity is paramount in the design of catalysts for green chemical processes towards minimizing the production of undesired products. We demonstrated that catalytic selectivity for production of alkene through oxidative dehydrogenation of alkane on transition metal oxides can be promoted through tailoring the surface lattice of the oxide catalyst. Selectivity for production of ethylene through oxidative dehydrogenation (ODH) of ethane on Co3O4 nanocrystals can be substantially increased by 30%–35% via temperature-mediated reconstruction of surface lattice of Co3O4. Co3O4 nanocrystals formed at 800 °C leads to smooth, flat crystal plane with predominantly exposed (111) facet in contrast to high Miller index (311) facet of Co3O4 formed at ≤700 °C, revealed by environmental transmission electron microscopy. Isotope-labelled experiments suggest that the higher catalytic selectivity on the (111) facet results from the lower activity of its surface lattice oxygen atoms. Consistent with these experimental results, DFT calculations suggest low activity of surface lattice oxygen atoms and high activation barriers for adsorption and dissociation of CH bond on the (111) surface in contrast to (311). Upon the activation of CH on (311), the stronger binding of ethylene on more active, under-coordinated surface lattice oxygen atoms of (311) forms a robust “deprotonated ethylene glycol”-like intermediate on (311) with a rate-limiting desorption barrier to the formation of ethylene. Compared to (311), the kinetically favorable desorption of bound ethylene species from (111) surface well rationalized the higher selectivity for production of ethylene on (111) than (311). These findings demonstrate that temperature-mediated tailoring of the surface lattice for a transition metal oxide nanocatalyst is a promising approach in pursuing high selectivity in oxidative dehydrogenation of hydrocarbons.Graphical abstractGraphical abstract for this article
       
  • Enhanced photocatalytic performance of a two-dimensional BiOIO3/g-C3N4
           heterostructured composite with a Z-scheme configuration
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Yan Gong, Xie Quan, Hongtao Yu, Shuo Chen, Huimin Zhao The construction of efficient photocatalytic systems has received considerable attention in the fields of water splitting and environmental remediation because of the great potential of these systems to solve the current energy-related and environmental problems. Herein, a two-dimensional BiOIO3/graphitic carbon nitride (g-C3N4) heterostructured composite bearing BiOIO3 nanoplates coupled with g-C3N4 nanosheets has been fabricated through a facile electrostatic self-assembly method. The as-prepared hybrids exhibit significantly improved photocatalytic activities toward 2,4,6-trichlorophenol (2,4,6-TCP) degradation and hydrogen evolution in water splitting under simulated solar light irradiation over those of bare g-C3N4. The apparent rate constant, k, for 2,4,6-TCP degradation (0.97 h−1) and the hydrogen evolution rate (56.4 μmol h−1) of the BiOIO3/g-C3N4 composites are approximately 4.8 and 3.5 times higher, respectively, than those of g-C3N4. The outstanding activity of the hybrids arises from the Z-scheme charge transfer mode, which imparts a superior photogenerated carrier separation ability and strong redox capability. In this Z-scheme, the I3−/I− redox pairs formed at the contact interface between BiOIO3 and g-C3N4 act as electron mediators. This work provides insight into the rational design of other two-dimensional Z-scheme composites with applications in solar energy conversion and environmental remediation.Graphical abstractGraphical abstract for this article
       
  • Enhancing ROS generation and suppressing toxic intermediate production in
           photocatalytic NO oxidation on O/Ba co-functionalized amorphous carbon
           nitride
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Wen Cui, Jieyuan Li, Yanjuan Sun, Hong Wang, Guangming Jiang, S.C. Lee, Fan Dong The generation of toxic intermediates during the photocatalytic reaction can result in the accumulation of secondary pollutants and lead to decreased performance. Here, we first designed an O/Ba co-functionalized amorphous carbon nitride (labeled as O-ACN-Ba) by conducting targeted density functional theory calculations for short-range and directional charge transfer in electronic transportation channels. Also, the O-ACN-Ba is synthesized via a one-step in situ co-pyrolysis of urea and BaCO3. The unique electronic structure O-ACN-Ba enables highly enhanced photocatalytic NO removal rate and suppresses the generation of toxic intermediate (NO2). The O and Ba are co-functionalized as a surface electronic trapping adjuster and an interlayer electronic trapping mediator to induce the convergence and localization of intralayer-delocalized electrons. Such internal electronic structure can facilitate the adsorption and activation of NO and O2, elongate the lifetime of photogenerated carriers, and expedite the spatial charge separation to boost significantly the generation of reactive oxygen species, thus suppressing toxic NO2 generation. In addition, the photocatalytic NO conversion pathway on O-ACN-Ba is characterized, and an important reaction intermediate—nitrosyl species Ba-NOδ(+) is discovered and found to promote the selective conversion of NO to final products (nitrites or nitrates). This work proposes a novel strategy to advance the application of photocatalytic technology for efficient and safe air purification.Graphical abstractTOC Art: An O/Ba co-functionalized amorphous carbon nitride (labeled as O-ACN-Ba) for short-range and directional charge transfer in electronic transportation channels has been designed, and subsequently synthesized via a one-step in situ co-pyrolysis of urea and BaCO3. The unique electronic structure O-ACN-Ba enable highly enhanced photocatalytic NO removal and suppressed toxic intermediate (NO2) generation.Graphical abstract for this article
       
  • Effective catalysts for the low-temperature NH3-SCR process based on
           MCM-41 modified with copper by template ion-exchange (TIE) method
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Andrzej Kowalczyk, Aneta Święs, Barbara Gil, Małgorzata Rutkowska, Zofia Piwowarska, Aleksandra Borcuch, Marek Michalik, Lucjan Chmielarz Effective catalysts for the low-temperature process of selective catalytic reduction of NO with ammonia (NH3-SCR) were obtained by deposition of copper species on MCM-41 using template ion-exchange method (TIE). It was shown that the form and aggregation of deposited copper species depend on concentration of copper salt (CuCl2) solution and solvent composition used for TIE procedure. In the case of methanol solution of CuCl2 copper in the highly dispersed form, mainly monomeric species, was deposited on the silica support, while in the case of water containing solutions of CuCl2 more aggregated CuO species were formed. The efficiency in deposition of highly dispersed copper species was significantly improved by treatment of the MCM-41 samples with ammonia directly after TIE procedure. In this case nearly 13 wt.% of copper was deposited on MCM-41 nearly exclusively in the form of monomeric cations. The catalysts obtained by this method presented high activity, selectivity to N2 and stability in the low-temperature (200–300 °C) NH3-SCR process.Graphical abstractGraphical abstract for this article
       
  • Construction 0D/2D heterojunction by highly dispersed Ni2P QDs loaded on
           the ultrathin g-C3N4 surface towards superhigh photocatalytic and
           photoelectric performance
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhiyuan Lu, Chunmei Li, Juan Han, Lei Wang, Shuhao Wang, Liang Ni, Yun Wang It is a hot topic to seek cheap and efficient cocatalyst to improve the activity of graphitic carbon nitride (g-C3N4) in photocatalytic water splitting to produce hydrogen and photoelectrochemical (PEC) performance. Herein, we prepared successfully the novel 0D/2D heterojunction by the modification of Ni2P quantum dots (QDs) as cocatalyst on the surface of ultrathin g-C3N4 layer, which can greatly enhance the photocatalytic hydrogen production and PEC performance under visible light owing to the improvement of separation efficiency of photogenerated charge carriers and visible-light absorption capacity. Surprisingly, the optimum amount of Ni2P loaded on the g-C3N4 is 3 wt%, whose hydrogen production rate is 1503 μmol h−1 g−1 being far superior to that of g-C3N4 decorated by 3 wt% Pt (560 μmol h−1 g−1). Moreover, the photocurrent response value of Ni2P/g-C3N4 photocatalyst is over 11 times and 3 times that of pure g-C3N4 and Pt/g-C3N4, respectively. What’s better, the stable photocatalytic H2 evolution and PEC performance of Ni2P/g-C3N4 demonstrates its high stability and reusability resulting from Ni-N coordination on the surface of g-C3N4. This work provides valid evidence for the development of cheap, efficient and durable cocatalyst actting on the g-C3N4, opening up new opportunities and possibilities for dual function application.Graphical abstractGraphical abstract for this article
       
  • Reducing the onset potential of CO2 electroreduction on CuRu
           bimetallic particles
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Joshua T. Billy, Anne C. Co Lower onset potentials for hydrocarbon products were observed during the electrochemical reduction of carbon dioxide (CO2RR) on copper particles (40–60 nm) coated with a thin layer of ruthenium via galvanic displacement, referred to as Ru@Cu. Hydrocarbons detected include ethane, ethylene, acetate, ethanol, propanol and CO. In the case of ethane (C2H6), the onset potential is 200 mV lower on Ru@Cu than on bare Cu particles. Increasing Ru coverage decreases the CO2RR activity while hydrogen evolution (HER) activity increased substantially. An optimum Ru coverage was found when the displacement was performed for 10 s. The results presented here highlight the importance of surface chemistry in determining reaction selectivity.Graphical abstractGraphical abstract for this article
       
  • Selective methane production from visible-light-driven photocatalytic
           carbon dioxide reduction using the surface plasmon resonance effect of
           superfine silver nanoparticles anchored on lithium titanium dioxide
           nanocubes (Ag@LixTiO2)
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Jeong Yeon Do, Rama Krishna Chava, Kotesh Kumar Mandari, No-Kuk Park, Ho-Jung Ryu, Myung Won Seo, Doyeon Lee, T.S. Senthil, Misook Kang This study focused on the results of applying the strong surface plasmon resonance (SPR) effect of silver (Ag) particles anchored on cubic phase LixTiO2 to the carbon dioxide (CO2) photoreduction reaction. The study demonstrated the importance of three aspects: First, the cubic TiO2, which activated the [101] facet, was successfully produced. Secondly, Li+ ions were introduced as Frenkel defects in some lattices to create oxygen defects. These vacancies increased the adsorption of carbon dioxide and sped up the rate-determining step in the CO2 reduction reaction. In other words, they induced the easy conversion of CO2 to CO, which is the first reduction product. Finally, the loading of Ag nanoparticles onto the LixTiO2 cubic surface the improved photocatalytic activity through SPR effects, and in particular led to selective conversion of CO2 to methane (CH4). Quantitatively, the yield of CH4 from CO2 using the Ag@Li0.075TiO2 particles was 49 μmol/g after 10 h of reaction, which was 8.2 and 1.5 times higher than that of cubic TiO2 (6 μmol/g) and Li0.075TiO2 (33 μmol/g) under UV-light. Additionally, its activity did not decrease under visible lights of 420 and 620 nm with the similar CH4 yields of 42 and 34 μmol/g after 10 h, respectively. In particular, the production ratio of CH4 and CO using cubic TiO2 and LixTiO2 were about 1:1, with no selectivity for either product. However, after metallic Ag nanoparticles were loaded, the product selectivity shifted towards CH4, and the product ratio of CH4 to CO was about 3:1. Furthermore, the Ag@Li0.075TiO2 particles exhibited a strong SPR effect (in particular, direct electron transfer), which contributed to maintaining the charge separation and the lifetime of the catalyst over a long period. Catalytic deactivation was not observed during five cycles of recycling tests.Graphical abstractSelective methane production from visible-light-driven photocatalytic carbon dioxide reduction using the surface plasmon resonance effect of superfine silver nanoparticles anchored on lithium titanium dioxide nanocubes (Ag@LixTiO2).Graphical abstract for this article
       
  • A photo-excited electron transfer hyperchannel constructed in Pt-dispersed
           pyrimidine-modified carbon nitride for remarkably enhanced water-splitting
           photocatalytic activity
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Xixiong Jin, Lingxia Zhang, Xiangqian Fan, Jianjian Tian, Min Wang, Jianlin Shi Electron transfer kinetics plays a crucial role in water-splitting hydrogen evolution reaction, and accelerating the electron transfer while preventing charge recombination are one of the key factors in improving solar-fuel conversion. Here, we report the construction of a photo-excited electron transfer hyperchannel in Pt-dispersed pyrimidine-modified carbon nitride (PMCN) for remarkably enhanced water-splitting photocatalytic activity. The electrophilic pyrimidine groups were incorporated in polymeric carbon nitride (CN) to withdraw photo-excited electrons upon illumination and in the meantime donate the electrons to the wherein anchored Pt particles, providing fast electron transfer hyperchannels across the catalyst interface, which greatly promoted the photo-excited electron/hole separation and prevented their recombination. As a result, Pt-anchored PMCN exhibited remarkably enhanced photocatalytic performance, with the highest H2 evolution under visible light irradiation reaching 3279.7 μmol h−1 g−1 and AQY% being 6% at 420 nm, 15.3 times higher than that of CN. The construction of electron transfer hyperchannel introduced a novel, facile and effective strategy to promote charge separation, presenting a new viewpoint for the rational design of photocatalysts to achieve improved solar-fuel conversion.Graphical abstractAccelerated photo-excited electron transfer from polymeric carbon nitride to Pt particles via pyrimidine-hyperchannel across the metal-support interface.Graphical abstract for this article
       
  • High performance hierarchical SiCN nanowires for efficient photocatalytic
           - photoelectrocatalytic and supercapacitor applications
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): I. Neelakanta Reddy, Adem Sreedhar, Ch. Venkata Reddy, Jaesool Shim, Migyung Cho, Kisoo Yoo, Dongseob Kim, Jin Seog Gwag We synthesized SiCN nanowires by a combination of high-energy ball milling and post-heat treatment using high-purity silicon and carbon nanopowders (
       
  • C+scission+at+low+potentials&rft.title=Applied+Catalysis+B:+Environmental&rft.issn=0926-3373&rft.date=&rft.volume=">Two-dimensional Pd-nanosheets as efficient electrocatalysts for ethanol
           electrooxidation. Evidences of the CC scission at low potentials
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Majid Farsadrooh, Jorge Torrero, Laura Pascual, Miguel A. Peña, María Retuerto, Sergio Rojas Pd-nanosheets with a lateral size of ca. 5 nm have been prepared by a simple chemical method. The Pd-nanosheets obtained exhibited a 2D morphology in which Pd atoms are preferentially exposed at the surface of the particles. In addition, a preferential exposure of Pd atoms in 111 planes is observed. As a result, the Pd-nanosheets exhibit a very high catalytic activity for the electrooxidation of ethanol in alkaline electrolyte, superior to that of commercial nanosized Pd particles. In situ infrared studies conducted during the electrooxidation of ethanol reveal that the scission of the CC bond of ethanol takes place at the surface of Pd-nanosheets at low potentials (as low as 30 mV). However, at higher potentials, the formation of partially oxidized species, typically acetates, is the preferred reaction pathway.Graphical abstractGraphical abstract for this article
       
  • Rare earth oxide doping and synthesis of spinel ZnMn2O4/KIT-1 with double
           gyroidal mesopores for desulfurization nature of hot coal gas
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Qiang Liu, Zhaofei Zhang, Bingsi Liu, Hong Xia In this work, spinel ZnMn2O4/KIT-1 using KIT-1 with 3-dimensional wormhole-like channels as support was fabricated for hot coal gas desulfurization at high temperature via a sol-gel method. Effects of ZnMn2O4 contents, desulfurization temperature, rare earth oxide doping and steam volume on the desulfurization performances of ZnMn2O4/KIT-1 were investigated systematically. A superior sorbent of ZnMn(Ce)2O4/KIT-1 was obtained with the addition of 45%ZnMn2O4 and doping of CeO2, which was suitable for 550 °C desulfurization and endured a small impact of steam. Moreover, the crystal lattice replace between Ce3+ and Mn3+ facilitated the dispersion of active species and avoided Zn2+ converting to elemental Zn. The high sulfur capacity of ZnMn(Ce)2O4/KIT-1 was maintained after five consecutive desulfurization-regeneration cycles. The textural properties of sorbents were evaluated successively by means of XRD, BET, HRTEM, XPS, H2-TPR and TG/DSC techniques. Results revealed that the main active components in sorbent were robustly existed in form of ZnMn2O4 spinel which effectually prevented the vaporization of Zn in high temperature. Therefore, a low-cost sorbent of ZnMn(Ce)2O4/KIT-1 with the high BSC (171.7 mg S/g sorbent) has an excellent performance for H2S removal from hot coal gas.Graphical abstractGraphical abstract for this article
       
  • Oxidation of residual methane from VNG vehicles over Co3O4-based
           catalysts: Comparison among bulk, Al2O3-supported and Ce-doped catalysts
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Andoni Choya, Beatriz de Rivas, Juan Ramón González-Velasco, Jose Ignacio Gutiérrez-Ortiz, Rubén López-Fonseca Cobalt oxide based catalysts with three different active phase configurations, namely bulk, alumina supported and cerium-doped Co3O4 samples were examined for the complete oxidation of methane under conditions similar to those found in the exhaust of VNG engines. The structural and redox properties of the resulting catalysts were determined by N2 adsorption-desorption, WDXRF, ICP-AES, X-Ray diffraction, temperature-programmed reactions, UV–vis-NIR DRS, XPS and Raman spectroscopy. Alumina-supported catalysts (10–40%wt. Co) were found to be less active, since the strong interactions between the alumina and the Co3O4 active phase were highly detrimental for the redox properties of these catalysts. On the other hand, doping with cerium (10%wt.) led to an increased inherent activity of the Co3O4 phase by distorting the spinel lattice, which resulted in improved structural and redox properties and enhanced mobility of the oxygen species within the spinel lattice. These catalysts were also stable over a prolonged period of time under both dry and humid conditions (150 h).Graphical abstractGraphical abstract for this article
       
  • Improving stability of cyclopentanone aldol condensation MgO-based
           catalysts by surface hydrophobization with organosilanes
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Duong T. Ngo, Tawan Sooknoi, Daniel E. Resasco Cyclopentanone is a promising building block in the conversion of biomass to fuels. It can be readily obtained from furanics derived from biomass and can be converted to intermediate products in the molecular weight range compatible with fuels via CC bond forming reactions. Among them, aldol condensation is a promising route. Conventional MgO catalysts are intrinsically active to catalyze this reaction, but they usually exhibit low surface areas and low stability in the presence of liquid water. The nitrate-citrate combustion method results in high surface area oxides with high condensation activity, but they are still susceptible to water attack. Here, we show that hydrophobic MgO-based catalysts functionalized with octadecyltrichlorosilane (OTS) exhibit remarkable stability in the liquid phase under conditions in which a conventional MgO deactivates in short time.Graphical abstractGraphical abstract for this article
       
  • Co4N/nitrogen-doped graphene: A non-noble metal oxygen reduction
           electrocatalyst for alkaline fuel cells
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Tamás Varga, Gergő Ballai, Lívia Vásárhelyi, Henrik Haspel, Ákos Kukovecz, Zoltán Kónya Cobalt-nitride (Co4N) nanoparticle-decorated nitrogen-doped graphene sheets were obtained via the nitrogen doping of a graphene-oxide precursor and simultaneous nitride formation. The non-precious metal catalyst formed in this one-step synthesis exhibits high electrocatalytic oxygen reduction activity and hence provides a promising alternative to conventional Pt/C alkaline fuel cell cathode catalysts. The reported composites were formed from the mixture of lyophilized graphene-oxide nanosheets and cobalt(II) acetate in ammonia atmosphere at 600 °C. The average Co4N particle size increased from 14 to 201 nm with the increase in cobalt content. The oxygen reduction activity of the new catalysts was comparable to that of non-noble metal systems described in the literature, and also to the widely-used carbon black supported platinum catalysts. The highest reduction current density under alkaline conditions was found to be as high as 4.1 mA cm−2 with the corresponding electron transfer number of 3.6. Moreover, the new system outperformed platinum-based composites in terms of methanol tolerance, thus eliminating one of the major drawbacks (besides high price and limited availability), of noble metal catalysts.Graphical abstractGraphical abstract for this article
       
  • CO2 methanation over nickel-ZrO2 catalyst supported on carbon nanotubes: A
           comparison between two impregnation strategies
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): M. Romero-Sáez, A.B. Dongil, N. Benito, R. Espinoza-González, N. Escalona, F. Gracia Ni-ZrO2 catalysts supported on CNT synthesized by sequential and co-impregnation were tested in the CO2 methanation reaction. The catalysts were characterized using different physico-chemical techniques including BET surface area analysis, TGA, H2-TPR analysis, CO2-TPD analysis, XRD analysis, TEM-EDS analysis and XPS. Both samples were found to be active in the CO2 methanation; however, the catalyst prepared by co-impregnation was notably less active and selective to CH4 than the catalyst synthesized by sequential impregnation method. The characterization results gave significant insight on the disposition of active phases in CNT surface. The catalyst prepared by co-impregnation showed NiO nanoparticles surrounded by ZrO2 in core-shell structures that growth over the CNT, reducing reactant access to Ni and Ni – ZrO2 interface. Additionally, TEM analysis of this catalyst prepared by sequential impregnation showed NiO nanoparticles available and deposited either on the surface or next to the ZrO2 nanoparticles, increasing the extent of the Ni – ZrO2 interface thus improving the catalytic performance.Graphical abstractGraphical abstract for this article
       
  • Effect of TiO2 on Pt-Ru-based anodes for methanol
           electroreforming
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Bjorn Hasa, John Vakros, Alexandros D. Katsaounis This study examines the electrochemical reforming of methanol for hydrogen production using novel DSA type anodes (modified with TiO2) with low metal loadings. Mass spectrometry (MS) in conjunction with electrochemical techniques were used to study the performance of the process as well as crossover phenomena. The electrolysis process was carried out in a Polymer Electrode Membrane (PEM) electrolyzer comprised of a Pt-Ru modified with TiO2 anode, a commercial Pt/C cathode, and a Nafion 117 electrolyte. Both methanol concentration and cell temperature were varied to investigate the cell performance. In all cases, our results showed that the Pt-Ru-TiO2 electrode had better electro-catalytic activity than the Pt-Ru electrode. This higher electro-catalytic activity of the TiO2-modified electrode was attributed to the enhanced Pt-Ru dispersion as well as the formation of smaller Pt and Ru particles, and thus to the higher electrochemical active surface. For all studied Membrane Electrodes Assemblies (MEAs), both CO2 and methanol crossover were observed at the cathode of the cell. In addition, it was found that hydrogen production is taking place with Faradaic efficiency values very close to 100%. This study demonstrates that the TiO2-modified electrode with a decreased noble-metal loading can increase the current density up to 56%.Graphical abstractGraphical abstract for this article
       
  • Ball-flower like NiO/g-C3N4 heterojunction for efficient visible light
           photocatalytic CO2 reduction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Jun-ying Tang, Rui-tang Guo, Wei-guo Zhou, Chun-ying Huang, Wei-guo Pan A ball-flower like NiO/g-C3N4 heterojunction composite was synthesized via a hydrothermal deposition method combined with subsequent calcination route. The NiO/g-C3N4 heterojunction exhibited a superior performance in CO2 photoreduction. A maximum CO yields of 4.17 μmol/(h g-cat) had been obtained on 40% NiO/g-C3N4 composite, which was 2.5 and 7.6 times as high as the pure g-C3N4 and NiO respectively. The promotion mechanism could be ascribed to the perfect band matching and efficient internal charge transfer within the p-n junction, which results in high-efficiency separation of photogenerated electron-hole pairs, strong visible-light response and high specific surface area.Graphical abstractGraphical abstract for this article
       
  • Anchoring MWCNTs to 3D honeycomb ZnO/GaN heterostructures to enhancing
           photoelectrochemical water oxidation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Santosh S. Patil, Muhammad Ali Johar, Mostafa Afifi Hassan, Deepak R. Patil, Sang-Wan Ryu Gallium nitride (GaN) is one of the ubiquitously known photoanode for photoelectrochemical water splitting (PEC-WS) due to its tunable band gap and favorable band edge positions. However, the unavoidable surface defects in GaN induces surface Fermi level pinning and surface band bending which severely reduces its PEC conversion efficiency. Constructing heterostructure is the key to approaching better charge separation efficiency and light harvesting ability for PEC-WS. Considering this, we have fabricated ternary heterostructure of GaN/ZnO/MWCNTs photoanode by combining metal organic chemical vapour deposition (MOCVD), hydrothermal and ‘dip and dry’ methods. FE-SEM results showed the formation of 3D hierarchical honeycomb structure of ZnO on GaN thin film surface when MWCNTs are added into hydrothermal reaction. We investigate the advantage of ZnO honeycomb structure in enhancing the solar PEC-WS performance of GaN photoanode. The synergy of incorporating MWCNTs has resulted into improvement in surface morphology, electron transportation and light harvesting capability. The as obtained ternary heterostructure exhibits photocurrent (Jph) of 3.02 mA/cm2 at 0 V versus Pt electrode under 1-sun light illumination which is about 2.58 times higher than that of pristine GaN photoanodes (Jph = 1.14 mA/cm2).Graphical abstractSynthesis of ternary heterostructure GaN/ZnO/MWCNTs with porous 3D hierarchical honeycomb structures has been demonstrated. As fabricated ternary heterostructure GaN/ZnO/MWCNTs photoanode promises unassisted PEC water splitting with enhanced photocurrent density of 3.02 mA/cm2, approximately ∼2.58 times higher than that of pristine GaN photoanode.Graphical abstract for this article
       
  • Collaborative enhancement of photon harvesting and charge carrier dynamics
           in carbon nitride photoelectrode
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Miaoyan Huang, Yan-Ling Zhao, Wei Xiong, Stephen V. Kershaw, Yaoguang Yu, Wan Li, Tatiana Dudka, Rui-Qin Zhang Target-oriented photoelectrochemical (PEC) performance can be enabled by regulating the physicochemical properties of graphitic carbon nitride (CN)-based photoanodes in the PEC process. Herein, we introduced boron heteroatoms into CN films (BCN) and explored the influence of the B heteroatom on the PEC performance experimentally and theoretically. B atoms favor substitution of carbon atoms at bay sites in BCN films and reduce the bandgap by raising the valence band edge as well as constructing optimal electronic structures for PEC hydrogen production. The as-prepared BCN films exhibit nearly 4 times higher photocurrent density than that of pristine CN films. We demonstrate that such enhancement originates from the spatially complementary orbital distribution over the BCN films, thus expediting the charge carrier separation. This work proposes ideal empirical routines for multiple functionalization of CN films for diverse PEC activities via component tailored strategies.Graphical abstractGraphical abstract for this article
       
  • Hydrogenated heterojunction of boron nitride and titania enables the
           photocatalytic generation of H2 in the absence of noble metal catalysts
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zuoli He, Chuhyung Kim, Tae Hwa Jeon, Wonyong Choi The increasing need for new materials capable of solar fuel production is central to the development of green energy economy. Utilizing solar energy for hydrogen generation is a great challenge due to inefficient light utilization and fast charge recombination. In this work, disorder-engineered black H-TiO2@BN with Ti-B chemically bonded interfaces was synthesized by employing BN nanosheets as the photocatalyst support. The hybridization of TiO2 with BN and hydrogenated thermal treatment work synergistically to enable the photocatalytic H2 production without noble metal cocatalysts. The hybrid photocatalyst markedly enhanced light absorption, significantly retarded charge pair recombination, facilitated interfacial electron transfer, and lowered interfacial charge transfer resistance. As a result, the photocatalytic H2 production activity of H-TiO2@BN that consisted of earth-abundant elements only was comparable to that of Pt-TiO2. The present hybrid engineering for the efficient charge separation and transfer via the formation of the interfacial chemical bonds should provide a useful methodology for designing the new types of hybrid photocatalysts.Graphical abstractHydrogenated Heterojunction of Boron Nitride and Titania, disorder-engineered black H-TiO2@BN with Ti-B chemically bonded interfaces was synthesized by employing BN nanosheets as the photocatalyst support. The hybridization of TiO2 with BN and the hydrogenated thermal treatment work synergistically to enable the photocatalytic H2 production without noble metal cocatalysts. The hybrid photocatalysts markedly enhanced light absorption, significantly retarded charge pair recombination, facilitated interfacial electron transfer and lowered interfacial charge transfer resistance.Graphical abstract for this article
       
  • An antenna/spacer/reflector based Au/BiVO4/WO3/Au nanopatterned photoanode
           for plasmon-enhanced photoelectrochemical water splitting
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Bin Chen, Zhuo Zhang, Minki Baek, Sangkuk Kim, Wooyul Kim, Kijung Yong BiVO4 is one of the most promising photoanodes for photoelectrochemical (PEC) water splitting. However, BiVO4 is limited by less-than-unity efficiencies of light absorption and charge separation due to a trade-off between the long penetration depth of photons and relatively short length carrier diffusion. Here, an antenna/spacer/reflector based Au/BiVO4/WO3/Au nanopatterned photoanode is designed by integrating ultrathin BiVO4 layer between two kinds of Au nanospheres (NSs) with different sizes. The large underlying nanopatterned Au NSs sever as current collector and back reflector to reflect the incident light by Bragg reflection of the highly ordered Au NSs array, while the small surface Au NSs act as antennas to absorb the incident and reflected light, which concentrates the light energy to the BiVO4 layer. Moreover, a strong electromagnetic field is created in the BiVO4 spacer due to the coupling interaction between the reflector and antenna, which promotes the charge separation of BiVO4. Based on this unique antenna/spacer/reflector structure, the ultrathin BiVO4 of only 70 nm achieves a photocurrent density of 1.31 mA/cm2 at 1.23 VRHE, which demonstrates an impressive 3.23 fold enhancement by the combined plasmonic effects, and it further increases to 1.97 mA/cm2 after depositing FeOOH catalyst. The strategy paves a way for other semiconductors and thin-film optoelectronic devices to improve their performance.Graphical abstractGraphical abstract for this article
       
  • Metal-support interaction in catalysis: The influence of the morphology of
           a nano-oxide domain on catalytic activity
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Sharif Najafishirtari, Clara Guglieri, Sergio Marras, Alice Scarpellini, Rosaria Brescia, Mirko Prato, Giulia Righi, Anna Franchini, Rita Magri, Liberato Manna, Massimo Colombo Using wet chemistry synthesis methods we prepared nanodumbbell structures as a model oxide supported metal catalyst. In this peculiar configuration, a single metallic domain (M) is connected to a single metal oxide (MOx) one. The size, composition and morphology of each domain can be carefully controlled, allowing us to investigate the effects resulting from a hollow morphology of the MOx domains, while all other material’s properties were kept constant. We chose the CO oxidation as a model oxidation reaction and increasing the population of nanocrystals (NCs) with hollow oxide domains resulted in a decrease in catalytic activity. Despite the manipulation of oxide morphology affected the surface charge of the Au domain, the bulk oxide reducibility and the crystallinity of the nanosized oxide support, the rate limiting step of CO oxidation was not affected. The same apparent activation energy was indeed measured independently from the population of NCs with hollow oxide domains. The difference in catalytic performance was thus ascribed to a different number of interfacial active sites when the morphology evolved from full to hollow.Graphical abstractGraphical abstract for this article
       
  • Surface electric field driven directional charge separation on Ta3N5
           cuboids enhancing photocatalytic solar energy conversion
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Chenguang Zhou, Junkang Zhou, Lei Lu, Jiajia Wang, Zhan Shi, Bing Wang, Lang Pei, Shicheng Yan, Yu Zhentao, Zhigang Zou Enhancing the separation and transfer of photogenerated carriers is critical factor for increasing the light to chemical energy conversion efficiencies. Here, we exposed {001} and {010} facets on [100] oriented Ta3N5 cuboid, creating 18.6 times enhancement in photocatalytic reduction of CO2 to CH4 and a 0.42 VRHE (reference to reversible hydrogen electrode) photocurrent onset potential for photoelectrochemical water splitting. The pronounced photocatalytic performance is mainly attributed to that surface electric field from large surface band bending of the {001} with high work function drives electrons and holes to {010} and {001}, respectively, achieving a spatial charge separation. Differing to a main effect in charge separation and transfer for the traditional junction electric field region at buried heterjunction or homojunction interface, a surface electric field region is a place where charges separate and transfer efficiently and also the place for the catalytic reactions to occur.Graphical abstractGraphical abstract for this article
       
  • Plasmonic-based nanomaterials for environmental remediation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Dawei Wang, Suresh C. Pillai, Shih-Hsin Ho, Jingbin Zeng, Yi Li, Dionysios D. Dionysiou Technologies based on nanomaterials are gaining increased attention as a promising method for the removal of contaminants and inactivation/killing of pathogenic microorganisms. Plasmonic nanomaterials prove to be promising in this field due to their tailored properties, including optical, photothermal, conducive, and catalytic properties. These properties have been widely used for the design of efficient materials for the environmental applications by improving the light absorption efficiency, redox reaction kinetic rates, and charge separation efficiency. In the current review, the tailored properties of plasmonic nanomaterials and how they are employed for the design of efficient environment-functional materials are discussed in detail. A number of examples for the development of composite plasmonic nanostructures such as metal/semiconductor, metal/insulator/semiconductor, and metal/semiconductor/semiconductor are provided.In addition, the recent achievements in plasmonic nanomaterials for the removal of contaminants (in both liquid and gaseous media) and the inactivation of pathogenic microorganisms are described with a number of examples. The major challenges in employing plasmonic nanomaterials for environmental applications are identified as: (1) complete mineralization of contaminants must be achieved in some cases due to the potential risks of intermediates; (2) the cost of plasmonic nanomaterials and the associated treatment processes need to be significantly decreased; (3) the stability of plasmonic nanomaterials in real environmental matrices is urgently needed to be improved; (4) the ecological safety of these nanomaterials should be investigated extensively. However, it is expected that with continuous progress of this field, plasmonic nanotechnology can be used for environmental applications more widely, not only for the examples shown in the current review, but also for soil remediation, resource recovery during waste treatment processes, and detection of contaminants. Finally, the toxicity of engineered plasmonic nanomaterials, the possibility of their release, fate, and transformation, in the environment and subsequent impact on the health of ecosystem are also addressed in detail.Graphical abstractGraphical abstract for this article
       
  • Highly active P-doped sulfided NiMo/alumina HDS catalysts from Mo-blue by
           using saccharose as reducing agents precursor
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): José Escobar, María C. Barrera, Ana W. Gutiérrez, María A. Cortés-Jacome, Carlos Angeles-Chávez, José A. Toledo, Dora A. Solís-Casados Saccharose (SA) was used as organic additive in simultaneously impregnated P-doped NiMo/Al2O3 hydrodesulfurization (HDS) catalysts (Mo, Ni and P at 12, 3, and 1.6 wt%, respectively). One-pot impregnating solutions were prepared by MoO3 digestion (∼353 K) in diluted aqueous H3PO4, followed by 2NiCO3·3Ni(OH)2·4H2O addition. Saccharose (SA, SA/Ni = 0.5, 1–3) was dissolved in originally emerald-green impregnating solutions which changed to cobalt blue by room-temperature aging (2–4 days, depending on SA concentration) due to Mo-blue formation by partial molybdenum species reduction. After sulfiding of samples impregnated with SA shorter MoS2 slabs of enhanced stacking were observed (by HR-TEM). Ni and Mo dispersion and nickel sulfidability (as determined by XPS) increased with the amount of organic modifier. Enhanced hydrodesulfurization activity in dibenzothiophene HDS was registered for catalyst obtained from Mo-blue precursor as to that of corresponding materials obtained from conventional emerald-green NiMoP impregnating solutions (with or without SA). However, in solids at high saccharose content (SA/Ni = 3) enhanced “NiMoS” phase amount was not reflected in improved activity. Probably, excessive amount of carbonaceous deposits from SA residua decomposition during catalyst activation provoked partially plugged porous network (as determined by N2 physisorption) in sulfided formulations. That fact seemed to limit accessibility of reactant molecules to surface active sites. Mo-blue precursor obtained through monosaccharides partial reduction seemed to play decisive role in obtaining HDS catalysts of improved properties. Saccharose results a highly soluble, cheap and non-toxic environmentally-friendly additive to produce catalysts of enhanced HDS activity.Graphical abstractGraphical abstract for this article
       
  • Facile synthesis of graphene-phthalocyanine composites as oxygen reduction
           electrocatalysts in microbial fuel cells
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Barbara Mecheri, Valerio C.A. Ficca, Maida Aysla Costa de Oliveira, Alessandra D’Epifanio, Ernesto Placidi, Fabrizio Arciprete, Silvia Licoccia In the path of direct energy conversion and wastewater disposal through microbial fuel cells (MFCs), the oxygen reduction reaction (ORR) plays a pivotal role. However, kinetic limitations hinders the spread of such technology requiring the use of a catalyst to develop efficient and cost effective devices. Herein we report a facile method for the preparation of iron-based catalyst supported on graphene oxide (GO) obtained by electrochemical exfoliation of graphite in aqueous solution of ammonium sulfate. Two different strategies to include nitrogen functionalities on/in GO matrix have been used, such as one-step nitrogen-doping in solution and post treatments based on annealing with ammonia gas. Iron (II) phthalocyanine (FePc) was used as iron source and deposited on GO by pyrolysis-free impregnation. Tuning the adjustable parameters governing the materials preparation allowed producing GO nanosheets with unique morphology and surface properties for enhancing the interaction with FePc. By combining the use of microscopy, electrochemical and spectroscopic techniques, a correlation between structure and surface chemistry of the prepared materials with catalytic activity towards ORR was established. The applicability of iron-based materials as ORR cathodes was evaluated by assembling single chamber air-cathodes MFCs, which power and voltage generation over time were acquired. The obtained results demonstrated that FePc/GO-based electrocatalysts can be used for electricity generation and waste treatment at the cathode side of MFCs.Graphical abstractGraphical abstract for this article
       
  • Mn0.2Cd0.8S nanowires modified by CoP3 nanoparticles for highly efficient
           photocatalytic H2 evolution under visible light irradiation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Qun-Zeng Huang, Ze-Juan Tao, Li-Qun Ye, Hong-Chang Yao, Zhong-Jun Li Development of highly efficient and low-cost noble metal-free co-catalysts for photocatalytic H2 evolution from water splitting has been aiming at a long-term goal of a renewable hydrogen economy. Herein, a series of novel Mn0.2Cd0.8S/CoP3 composites have been successfully prepared through loading CoP3 nanoparticles on the surface of one dimensional (1D) Mn0.2Cd0.8S nanowires (NWs) by a facile solvothermal method. Under visible light (λ ≥ 420 nm) irradiation, the as-prepared Mn0.2Cd0.8S/CoP3 composite with 2.87 wt% of CoP3 displayed the highest photocatalytic H2 evolution activity with a corresponding H2 evolution rate of 29.53 mmol g−1 h−1 and an apparent quantum yield of 29.2% at 420 nm, which was about 5.02 times higher than that of pure Mn0.2Cd0.8S and 1.79 times than that of Mn0.2Cd0.8S/Pt-1.5 wt%. Moreover, the Mn0.2Cd0.8S/CoP3 composite exhibited excellent photostability. The superior photocatalytic activity of Mn0.2Cd0.8S/CoP3 composite was predominantly attributed to the synergistic effects of highly efficient charge separation efficiency and sufficient active sites for H2 evolution reaction. This work revealed that low-cost CoP3 can replace noble metal Pt as a highly efficient co-catalyst for enhancing the photocatalytic activity of semiconductor materials.Graphical abstractNovel Mn0.2Cd0.8S/CoP3 composite prepared by solvothermal method possessed sufficient contact interface and more active sites, which displayed a superior photocatalytic H2 evolution activity under visible light irradiation.Graphical abstract for this article
       
  • Halogen-hydrogen bonds: A general synthetic approach for highly
           photoactive carbon nitride with tunable properties
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Jesús Barrio, Andrea Grafmüller, Jonathan Tzadikov, Menny Shalom The design of the chemical, photo-physical, and catalytic properties of graphitic carbon nitride (g-CN) is highly challenging due to the harsh solid-state reaction. Here we report a template-free, large-scale synthesis of highly photoactive and stable g-CN with a unique dot-like morphology by using melamine-halogen complexes as starting precursor. The supramolecular structures are synthesized by sequential treatment of melamine with different acids. Experimental results together with theoretical calculations reveal that different halogens result in different interactions with melamine. We found that bromide reacts with the inner melamine aggregates while chloride is present mainly in the outer shell. Upon calcination, the delicate design results in porous carbon nitride with controlled morphologies and optical properties as well as improved charge separation under illumination and excellent photoactivity and stability for hydrogen production. Our results indicate that the type of halogen can significantly affect different properties in the final g-CN. This work provides new opportunities for template-free facile synthesis of highly photoactive carbon nitride and other carbon-nitrogen based materials with controllable chemical, optical, and catalytic properties for sustainable energy-related applications owing to the utilization of hydrogen-halogen based assemblies as well as the elucidation of their unique interaction.Graphical abstractGraphical abstract for this article
       
  • Enhanced CO2 reduction activity of polyethylene glycol-modified Au
           nanoparticles prepared via liquid medium sputtering
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Min Wook Chung, In Young Cha, Min Gwan Ha, Youngseung Na, Jungsoo Hwang, Hyung Chul Ham, Hyoung-Juhn Kim, Dirk Henkensmeier, Sung Jong Yoo, Jin Young Kim, So Young Lee, Hyun S. Park, Jong Hyun Jang The electrochemical conversion of CO2 into useful chemicals such as CO is a promising strategy to reduce CO2 emissions from fossil fuel consumption and to mitigate the impacts of global warming. Although tremendous effort has been devoted to the practical use of CO2conversion techniques, these techniques still suffer from deficient catalytic activity toward CO2 reduction as well as a complex catalyst synthesis procedure. In this study, an effective strategy to enhance the catalytic CO2 reduction activity with a unique synthesis method is proposed. Polyethylene glycol (PEG)-coated Au nanoparticles supported on a porous carbon support are prepared by a facile, cost-effective, and biocompatible one-step sputtering deposition method, termed liquid medium sputtering. The use of PEG as a liquid medium is advantageous in terms of catalytic activity and stability by producing PEG layers on the Au surface. The prepared PEG-coated Au nanoparticle catalyst exhibits a CO Faradaic efficiency of 100% at −0.57 VRHE and excellent stability during 10 h of operation due to the high solubility of PEG for CO2.Graphical abstractPolyethylene glycol coated Au nanoparticles showed enhanced electrocatalytic activity toward CO2 reduction reaction likely due to the enhanced CO2 concentration at the catalytic surfaces.Graphical abstract for this article
       
  • Low onset potential on single crystal Ta3N5 polyhedron array photoanode
           with preferential exposure of {001} facets
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhan Shi, Jianyong Feng, Hao Shan, Xin Wang, Zhe Xu, Huiting Huang, Qinfeng Qian, Shicheng Yan, Zhigang Zou The photoelectrochemical performance of photoanode depends significantly on the surface properties. Enormous efforts have been spent on fabricating photoanode with exposure of high-activity facets. However, precise control of the Ta3N5 facet exposure is still highly challenging, due to its harsh fabrication condition. In this study, it was found that Ta3N5 polyhedron can be grew through a bottom-up growth process in molten salt. Molten salt media in a semi-closed reactor provides a steady growth environment so that the Ta3N5 growth units are able to assemble in thermodynamically and kinetically favorable way. The preferential exposed facets are determined to be {001} facets. Due to the stronger built-in electric field on {001} facets and the small effective mass of hole along the [001] axis, an onset potential of 0.6 V versus reversible hydrogen electrode (RHE) and a photocurrent of 5.6 mA cm−2 at 1.23 versus RHE have been achieved. Our findings may open an avenue to grow the nitride or oxynitride semiconductor crystals with desired structures for achieving efficient solar energy conversion and storage.Graphical abstractGraphical abstract for this article
       
  • Photothermally promoted cleavage of β-1,4-glycosidic bonds of cellulosic
           biomass on Ir/HY catalyst under mild conditions
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Bao Zhang, Jun Li, Lin Guo, Zhenpan Chen, Can Li Cellulose represents the major component of the abundant and inedible lignocellulosic biomass on earth. The valorization of cellulose into liquid biofuels and high value-added bio-based chemicals has drawn intensive attentions in recent years. However, because of the rigid structure of crystalline cellulose, the breakage of β-1,4-glycosidic bonds, the first step of cellulosic biomass utilization is still a critical challenge under mild conditions. Herein, we report the cleavage of β-1,4-glycosidic bonds of cellobiose on Ir/HY catalyst with high activity and high selectivity (>99%) under visible light illumination at temperature not exceeding 100 °C. We found that the hydrolysis of cellobiose under mild condition is mainly owing to a cooperation effect between the Ir nanoparticles as the plasmonic photothermal source and acid catalysis of HY zeolite. This work provides a distinctive, sustainable pathway to efficiently convert cellulose to chemicals driven by solar energy under mild conditions.Graphical abstractGraphical abstract for this article
       
  • Dandelion-like cobalt oxide microsphere-supported RuCo bimetallic catalyst
           for highly efficient hydrogenolysis of 5-hydroxymethylfurfural
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhi Gao, Guoli Fan, Mengran Liu, Lan Yang, Feng Li Currently, renewable biomass-derived energy sources and related transformation technologies are attracting numerous attentions due to the rapid consumption of fossil fuels and resulting increasing environmental pollution. Herein, a new dandelion-like cobalt oxide (CoOx) microsphere-supported bimetallic RuCo catalyst was fabricated by a simple one-pot embedding method and employed for the 5-hydroxymethylfurfural (HMF) hydrogenolysis to produce liquid 2,5-dimethylfuran (DMF) biofuel. It was found that bimetallic RuCo nanoparticles (NPs) with the average size of about 2.5 nm could homogeneously disperse on flower-like CoOx microspheres possessing abundant surface defects (i.e. oxygen vacancies and Co2+ species) simultaneously constructed. As-fabricated RuCo/CoOx catalyst exhibited excellent catalytic performance in above reaction, along with a quite high DMF yield of 96.5% at a high HMF/Ru molar ratio of 252.7, which was corelated with the unique synergy between bimetallic RuCo NPs and abundant surface defects at the metal-support interface, as well as the enhanced hydrogen spillover effect and the dandelion-like superstructure of the catalyst. Additionally, the strong interactions between RuCo species and the CoOx matrix in the RuCo/CoOx significantly prevented RuCo NPs from migration, aggregation, and leaching during the reaction. The present findings offer a new approach for designing other highly efficient and stable bimetallic catalysts applied in a variety of heterogeneous catalytic systems.Graphical abstractGraphical abstract for this article
       
  • Tuning the catalytic performance of Ni-catalysed dry reforming of methane
           and carbon deposition via Ni-CeO2- x interaction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Maoshuai Li, André C. van Veen The role of tuning metal-support interaction in determining the catalytic activity and carbon formation in dry reforming of methane to syngas was examined over CeO2 supported Ni nanoparticles. The catalysts pre- and post- reaction were subjected to characterisation in terms of N2 physisorption, TPR, XRD, TEM, XPS and TGA-DTG. Reduction of Ni/CeO2 in H2 in the temperature range (773–973 K) generated a strong bonding between Ni and CeO2 that inhibited Ni particle sintering (8.7–9.4 nm). High-temperature (≥873 K) reduction induced decoration/encapsulation of Ni nanoparticles by a thin layer of reduced ceria support with partial coverage of Ni surface. The decoration/encapsulation effect strongly influences the catalytic properties of Ni, which enables to tune the catalytic activity of Ni/CeO2 and carbon deposition in dry reforming of methane.Graphical abstractGraphical abstract for this article
       
  • Ultrathin nanosheets g-C3N4@Bi2WO6 core-shell structure via low
           temperature reassembled strategy to promote photocatalytic activity
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Yingying Wang, Wenjun Jiang, Wenjiao Luo, Xianjie Chen, Yongfa Zhu In this work, ultrathin nanosheet g-C3N4@Bi2WO6 core-shell structure is fabricated by a new method of CN precursor in situ coating and low temperature reassembled. The CN small molecules were successfully polymerized to form ultrathin g-C3N4 layer (about 1 nm) on the surface of Bi2WO6 nanosheet under low temperature. And the g-C3N4@Bi2WO6 photocatalyst with 1 nm thickness of shell layers has the highest photocatalytic degradation phenol activity with visible light irradiation which is almost 5.7 times as high as that of bulk g-C3N4 and also 1.9 times compare to Bi2WO6 nanosheet. Simultaneously, phenol degradation activity by using g-C3N4@Bi2WO6 photocatalyst under full spectrum is 3.3 times that of bulk g-C3N4 and 1.5 times that of Bi2WO6 nanosheet. Superoxide radicals (O2−) and hydroxyl radicals (OH) as the main oxidative species proved by electron spin resonance spectroscopy (ESR). The interface catalytic system was found, that is the interface between the Bi2WO6 core and g-C3N4 shell effectively promote the phenol degradation activity revealed through a comprehensive contrast experiment. The establishment of g-C3N4@Bi2WO6 core-shell catalytic system can offer blueprints for the construction of other new interface catalytic system.Graphical abstractGraphical abstract for this article
       
  • Pt supported and carbon coated Bi2MoO6 composite for enhanced
           2,4–dibromophenol degradation under visible–light irradiation: Insight
           into band gap structure and photocatalytic mechanism
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Juan Wu, Yuying Sun, Chunhao Gu, Ting Wang, Yanjun Xin, Chao Chai, Chunyue Cui, Dong Ma This study aims to reveal the visible–light photocatalytic performance of Pt supported and carbon coated Bi2MoO6 (Pt/C@Bi2MoO6) composite on the degradation of aquatic 2,4–dibromophenol (DBP) pollutant. The surface structure analysis shows that Pt and carbon layer can tightly bind to the surface of Bi2MoO6 with the chemical bonds, and hybrid the original band gap to generate new impurity levels to enhance the visible–light utilization efficiency. The carbon layer has excellent conductivity to transformation electrons from valence band (VB) site, and the supported Pt atoms on carbon layer generate a plasma electron field to enhance the reductive activity on conduction band (CB) site. The Pt/C@Bi2MoO6 composite shows more efficient and reliable abilities in DBP photocatalytic degradation, and the debromination and oxidization processes are performed separately on CB and VB site, respectively. The DBP debromination proceeds by electrons in the CB site in priority to generate non–brominated intermediate products, and then the oxidization and mineralization procedures start by hydroxide radicals in the VB site to finish the complete degradation of DBP. This research reveals the important roles of Pt and carbon layer in band gap structure modification and photocatalytic activity improvement, exhibiting a new insight to design an efficient and stable photocatalyst for persistent organic pollutant degradation under visible–light irradiation.Graphical abstractGraphical abstract for this article
       
  • H-doped TiO2-x prepared with MgH2 for highly efficient solar-driven
           hydrogen production
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Apurba Sinhamahapatra, Ha-Young Lee, Shaohua Shen, Samuel S. Mao, Jong-Sung Yu Efficient utilization of visible light with high stability remains a critical challenge for solar-driven photochemical generation of hydrogen (H2) using particulate photocatalysts. Black TiO2 was introduced with remarkable enhancement of visible light absorption, but its efficiency in the visible light has not reached the desired level for real-world applications. Here we report a gold-colored H-doped TiO2-x (H:TiO2-x) nanoparticles prepared by controlled reduction via simultaneous presence of [Mg] and [H], which are obtained from the decomposition of MgH2. The H-doped TiO2-x exhibits a significant activity (16.1 mmolg−1h−1) and remarkable stability after Pt deposition for solar-driven H2 generation from methanol-water. The excellent photoactivity of H-doped TiO2 can be attributed to oxygen vacancies and H doping at the reduced TiO2-x surface generated by [Mg] and [H]. The H-doped TiO2 is also producing H2 from methanol-seawater with a rate of 6.1 mmolg−1h−1 under simulated sunlight.Graphical abstractThe simultaneous reduction and hydrogenation of TiO2 by [Mg] and [H], respectively, offer efficient hydrogen-doped reduced TiO2-x photocatalyst systems which exhibit high efficiency (16.1 mmolg−1h−1) for solar hydrogen production from methanol-water in the presence of only 0.25% of photodeposited Pt nanoparticles with excellent performance stability. The photocatalyst system possesses sufficient low recombination of the photogenerated charges and also utilizes a reasonable amount of visible light.Graphical abstract for this article
       
  • Charge carrier dynamics and visible light photocatalysis in vanadium-doped
           TiO2 nanoparticles
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Giacomo Rossi, Luca Pasquini, Daniele Catone, Alberto Piccioni, Nicola Patelli, Alessandra Paladini, Alessandra Molinari, Stefano Caramori, Patrick O’Keeffe, Federico Boscherini Vanadium-doped TiO2 nanoparticles (V-TiO2 NPs) with a V/Ti ratio of 3.0 at. % were prepared by gas-phase condensation and subsequent oxidation at elevated temperature. Both photocatalytic activity for -NO2 reduction and photoelectrochemical water splitting were induced by V-doping in the visible spectral range λ> 450 nm, where undoped TiO2 NPs are completely inactive. The photocatalytic properties were correlated with the ultrafast dynamics of the photoexcited charge carriers studied by femtosecond transient absorption (TA) spectroscopy with three different excitation wavelengths, i.e. λe = 330, 400, and 530 nm. Only in V-doped NPs, the photoexcitation of electrons into the conduction band by sub-bandgap irradiation (λe = 530 nm) was detected by TA spectroscopy. This observation was associated with electronic transitions from an intra-gap level localized on V4+ cations. The photoexcited electrons subsequently relaxed, with characteristic times of 200–500 ps depending on λe, into Ti-related surface traps that possessed suitable energy to promote -NO2 reduction. The photoexcited holes migrated to long-lived surface traps with sufficient overpotential for the oxidization of both 2-propanol and water. On the basis of TA spectroscopy and photocurrent measurements, the position of the dopant-induced intra-gap level was estimated as 2.2 eV below the conduction band minimum.Graphical abstractGraphical abstract for this article
       
  • Steady state and lean-rich cycling study of a three-way NOX
           storage catalyst: Experiments
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Sotirios A. Malamis, Mengmeng Li, William S. Epling, Michael P. Harold The three-way NOx storage catalyst (TWNSC) combines components from a conventional three-way catalyst (TWC) and NOX storage and reduction (NSR) catalyst to improve NOX emissions while exploiting the higher fuel economy of lean-burn gasoline vehicles. The performance of a commercial monolithic TWNSC was studied to understand the NOX trapping and reduction performance over a range of conditions with emphasis on identifying conditions leading to optimal performance in terms of a standalone TWNSC or one coupled with a downstream selective catalytic reduction (SCR) device. Using H2, CO, and C3H6 in various combinations, the impact of cycle timing (cycle time, rich duty fraction), reductant and O2 feed concentrations, and feed temperature on NOX conversion and product (N2, NH3, N2O) selectivities was determined. Steady state experiments were conducted to assess catalyst activity and selectivity and to help interpret the phenomena observed during lean-rich switching. Cycling experiments reveal maxima in the NOX conversion and ammonia-to-NOx ratio (ANR) at distinct, intermediate cycle times. The existence of operating conditions giving these maxima depends on the reductant type, feed temperature, and O2 feed concentration. For example, a large disparity in the lean/rich ratio (stoichiometric number) of the lean and rich feeds tends to lead to a NOx conversion maximum. Where possible, the data trends are interpreted in terms of known performance features of the TWC and NSR catalysts. The study findings provide guidance for optimizing the TWNSC formulation and operation strategy.Graphical abstractGraphical abstract for this article
       
  • Noble metal-modified faceted anatase titania photocatalysts: Octahedron
           versus decahedron
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhishun Wei, Marcin Janczarek, Maya Endo, Kunlei Wang, Armandas Balčytis, Akio Nitta, Maria G. Méndez-Medrano, Christophe Colbeau-Justin, Saulius Juodkazis, Bunsho Ohtani, Ewa Kowalska Octahedral anatase particles (OAP, with eight equivalent {101} facets) and decahedral anatase particles (DAP, with two additional {001} facets) were modified with nanoparticles of noble metals (Au, Ag, Cu). The titania morphology, expressed by the presence of different arrangements of exposed crystal facets, played a key role in the photocatalytic properties of metal-modified faceted titania. In the UV/vis systems, two-faceted configuration of DAP was more favorable for the reaction efficiency than single-faceted OAP because of an efficient charge separation described by the transfer of electrons to {101} facets and holes to {001} facets. Time-resolved microwave conductivity (TRMC) and reversed double-beam photoacoustic spectroscopy (RDB-PAS) confirmed that distribution of electron traps (ET) and mobility of electrons were key-factors of photocatalytic activity. In contrast, metal-modified OAP samples had higher photocatalytic activity than metal-modified DAP and metal-modified commercial titania samples under visible light irradiation. This indicates that the presence of single type of facets ({101}) is favorable for efficient electron transfer via shallow ET, whereas intrinsic properties of DAP result in fast charge carriers’ recombination when gold is deposited on {101} facets (migration of “hot” electrons: Au→{101}→Au).Graphical abstractGraphical abstract for this article
       
  • High efficient photocatalytic hydrogen evolution from formaldehyde over
           sensitized Ag@Ag-Pd alloy catalyst under visible light irradiation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Hongxia Liu, Meng Wang, Xuqiang Zhang, Jiantai Ma, Gongxuan Lu The development of an active but cheaper catalyst is critical for efficient photocatalytic hydrogen from renewable source. In this study, we develop a high active catalyst for hydrogen evolution from formaldehyde via alloying of Pd with Ag and sensitization with a dye eosin Y (EY). The XRD, XPS, TEM and HRTEM characterizations indicate that the catalyst exhibits a core-shell structure (Ag core and Ag-Pd shell). Alloying Pd with Ag not only provides more efficient catalytic sites than single component Pd catalyst, but greatly promotes the efficient electron transfer and prolongs the lifetime of photogenerated electrons, enhances the charge separation efficiency and the photocatalytic hydrogen evolution activity significantly. The catalyst activity for hydrogen is highly dependent on the adsorption energies of HCHO and H2O molecules on metal surface of the alloy catalyst. Our results disclose a new route to high efficient catalyst development for solar hydrogen generation from formaldehyde.Graphical abstractHigh active catalyst for hydrogen evolution from formaldehyde via alloying of Pd with Ag and sensitization with a dye (EY) has been developed. The XRD, XPS, TEM and HRTEM characterizations indicated that the catalyst exhibited a core-shell structure (Ag core and Ag-Pd shell). Alloying Pd with Ag not only provides more efficient catalytic sites than single component Pd catalyst, but greatly promotes the efficient electron transfer and prolongs the lifetime of photogenerated electrons, enhances the charge separation efficiency and the photocatalytic hydrogen evolution activity significantly. The catalyst activity for hydrogen is highly dependent on the adsorption energies of HCHO and H2O molecules on metal surface of the alloy catalyst.Graphical abstract for this article
       
  • Promoting effect of cerium on MoVTeNb mixed oxide catalyst for oxidative
           dehydrogenation of ethane to ethylene
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Yang Sik Yun, Minzae Lee, Jongbaek Sung, Danim Yun, Tae Yong Kim, Hongseok Park, Kyung Rok Lee, Chyan Kyung Song, Younhwa Kim, Joongwon Lee, Young-Jong Seo, In Kyu Song, Jongheop Yi Ce-incorporated MoVTeNbO catalysts were developed to enhance ethylene productivity of oxidative dehydrogenation of ethane (ODHE) to ethylene. Structural characterizations (XRD, TEM, STEM, Raman, and UV–vis DRS) and DFT calculations revealed that Ce atoms were incorporated into MoVTeNbO framework with maintaining its unique structure (M1 phase), which is active phase for ODHE. The reducibility of the catalysts was enhanced and both V5+ and the lattice oxygen species available to ODHE reaction were enriched by incorporation of Ce, confirmed by TPR, XPS, and pulse injection method, respectively. These improved properties enhanced the conversion of ethane while maintaining their excellent selectivity to ethylene for MoVTeNbCeO catalysts. It is noteworthy that 56.2% of ethane conversion and 95.4% of ethylene selectivity were retained for 200 h over MoVTeNbCeO-0.1 catalyst. Ethylene productivity was calculated to be 1.11 kgC2H4/kgcat h. The developed catalyst exhibits substantial level of ethylene productivity and stability having the possibility with low production of COx to make a step forward for industrialization of oxidative dehydrogenation of ethane.Graphical abstractGraphical abstract for this article
       
  • Steam reforming of acetic acid over nickel-based catalysts: The intrinsic
           effects of nickel precursors on behaviors of nickel catalysts
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhenjie Yu, Xun Hu, Peng Jia, Zhanming Zhang, Dehua Dong, Guangzhi Hu, Song Hu, Yi Wang, Jun Xiang The paper investigated the effects of various nickel precursors (Ni(NO3)2, NiCl2, NiSO4, Ni(CH3COO)2, Ni(NH2SO3)2) on the catalytic behaviors of Ni/Al2O3 catalysts in steam reforming of acetic acid, aiming to understand the fundamental influences of nickel metal precursors. The catalysts were characterized with TPR, TPO, TPR-MS, TPO-MS, XRD, TG-MS, FT-IR, FT-Raman, BET method, element analysis, TEM and SEM. The results revealed the substantial influence of the nickel precursors on properties of Ni/Al2O3 catalysts. The use of NiSO4 and Ni(NH2SO3)2 as nickel precursors led to the low activities of the catalysts, due to the formation of Ni3S2 during reduction of the catalysts with hydrogen. The sulfur species were removed in the form of SO2 during the calcination of the catalysts precursors in air and in the form of H2S during the reduction of the calcined catalyst in hydrogen. NiCl2/Al2O3 catalyst showed a negligible activity as the chlorine poisoned the catalyst and was difficult to be removed via calcination. Furthermore, chlorine could accelerate sintering of alumina. In comparison, Ni(CH3COO)2 as nickel precursor could effectively suppress the formation of NiAl2O4. Ni(CH3COO)2/Al2O3 catalyst showed comparable activity to that of Ni(NO3)2/Al2O3, but the resistivity towards coking was higher. In addition, the coke species produced over the catalysts have both large and small aromatic ring systems with the morphology of both amorphous and fibrous structures.Graphical abstractGraphical abstract for this article
       
  • One-pot hydrogen production and cascade reaction of furfural to
           bioproducts over bimetallic Pd-Ni TUD-1 type mesoporous catalysts
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Margarida M. Antunes, Sérgio Lima, Auguste Fernandes, Maria F. Ribeiro, David Chadwick, Klaus Hellgardt, Martyn Pillinger, Anabela A. Valente Bimetallic Pd-Ni TUD-1 type mesoporous catalysts are effective for the cascade reaction of the renewable platform chemical furfural (FUR) to the useful bioproducts 2-alkoxyfuran, 2-methylfuran (2MF), 4-oxopentanal and its acetals, which find diverse applications, some already in the market. With a single catalyst, the in situ hydrogen supply from formic acid (FAc), as well as several acid-reduction steps of the overall catalytic process were triggered, leading to the desired bioproducts (bioPs), all in one-pot under moderate reaction conditions. These multipurpose materials were prepared using different procedures and conditions, which influenced the material properties and the catalytic performances. Detailed characterisation (microstructural/molecular level) and catalytic studies led to new mechanistic insights into the FUR reaction (with identification of intermediates), allowed to assess the roles of the different types of metal species in the complex reaction mechanism, understand the influence of material properties on the catalytic process, and catalyst stability and regeneration. The best-performing catalyst was prepared stepwise via impregnation of palladium on a hydrothermally synthesised nickel silicate with a molar ratio Si/Ni of 20, ending with filtration-washing-calcination procedures. This catalyst led to 83% 2MF yield, at 98% FUR conversion (90% total bioPs yield), using 1-butanol as solvent, at 170 °C. The reported catalytic protocol benefits from the fact that external usage of H2 for catalyst activation and/or the catalytic reaction is not required, no high-pressure gases are used, and FAc is used as source of hydrogen supplied in situ for the catalytic reaction under moderate conditions. Moreover, FAc presents low toxicity, it is easy to handle/store, and is a typical coproduct of carbohydrate biomass conversion processes, and thus its repurposing is highly desirable.Graphical abstractGraphical abstract for this article
       
  • FeOOH quantum dots coupled g-C3N4 for visible light driving photo- Fenton
           degradation of organic pollutants
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Xufang Qian, Yunwen Wu, Miao Kan, Mengyuan Fang, Dongting Yue, Jun Zeng, Yixin Zhao Amorphous FeOOH quantum dots (QDs) were coupled with polymeric photocatalysts g-C3N4 which was developed as a visible light driving photo-Fenton catalyst. Highly dispersed FeOOH QDs anchored on g-C3N4 showed enhanced visible light driving photo-Fenton degradation of MO and phenol than that of pure g-C3N4 and mechanical mixture (FeOOH&g-C3N4). The mineralization efficiency on FeOOH/g-C3N4 is nearly 7 times higher than that on pure g-C3N4 which shows great potential in treatment of recalcitrant organic pollutants. XPS results indicated that extraneous carbon species were present in FeOOH/g-C3N4 which should be responsible for the electron transfer between FeOOH and g-C3N4. Based on the radical capture, electrochemical experiments and photoluminescence (PL) decay characterizations, we proposed that visible light excited the g-C3N4 to produce e−/h+ pairs and the e− participated the cycling of Fe(II)/Fe(III). The FeOOH/g-C3N4 showed high recycling stability without Fe leaching due to the interaction of FeOOH QDs and carbon species. The FeOOH QDs coupled g-C3N4 is a promising visible light driving photo-Fenton catalyst for organic pollutants treatment.Graphical abstractGraphical abstract for this article
       
  • Improved stability of Y2O3 supported Ni catalysts for CO2 methanation by
           precursor-determined metal-support interaction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Yong Yan, Yihu Dai, Yanhui Yang, Alexei A. Lapkin Y2O3 supported Ni catalysts were prepared from different Y precursors. The catalysts synthesized via Y4O(OH)9(NO3) and YO(NO3) as precursors exhibit superior activity in CO2 methanation reaction compared to the catalysts prepared by direct impregnation of Y2O3. YO(NO3) acts as a unique matrix to afford anchoring sites to interact with Ni2+ ions, leading to a moderate interaction between Ni metal and Y2O3 support, which translates into excellent catalytic activity and stability towards CO poisoning. In situ DRIFTS spectra confirm the reaction mechanism of Ni/Y2O3 catalyzed CO2 methanation with carbonates and formates as the key intermediates. The apparent difference in the rate of transformation of formates into methane determines catalytic activity of these Ni/Y2O3 catalysts. This work provides an effective strategy to achieve CO2 activation and resistance to CO poisoning through careful selection of precursor for the support, which allows to control the strength of metal-support interaction.Graphical abstractGraphical abstract for this article
       
  • Photo-assisted methanol oxidation on Pt-TiO2 catalysts for direct methanol
           fuel cells: A short review
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Ermete Antolini Platinum and platinum-based electrocatalysts for the methanol oxidation reaction (MOR) are commonly used as the anode material in direct methanol fuel cells (DMFCs). Photo-oxidation promoted by ultraviolet and visible light is a promising method to increase the catalytic activity of DMFC anode electrocatalysts. Photocatalytic and electrocatalytic methanol oxidation can be coupled by addition of TiO2, a semiconductor photocatalyst, to Pt. In the presence of TiO2, an increase of the MOR activity of Pt-based electrocatalysts takes place also in dark conditions. This review deals with the methanol photo-oxidation on Pt/TiO2 catalysts, highlighting the effect of TiO2 morphology, nanoparticles, or 1D nanostructures, on the MOR activity under illumination. Comparison of reaction mechanisms in the presence and the absence of light are presented, and the roles of Pt and TiO2 during electrochemical and photochemical reactions are discussed.Graphical abstractGraphical abstract for this article
       
  • Reagentless preparation of shape memory cellulose nanofibril aerogels
           decorated with Pd nanoparticles and their application in dye discoloration
           
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Jin Gu, Chuanshuang Hu, Weiwei Zhang, Anthony B. Dichiara An environmentally benign method was reported for synthesizing highly porous cellulose nanofibril (CNF) aerogels decorated with palladium nanoparticles (PdNPs). Small PdNPs (
       
  • Construction of a bifunctional electrode interface for efficient
           electrochemical mineralization of recalcitrant pollutants
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Shouning Chai, Yujing Wang, Ya-nan Zhang, Hongying Zhao, Meichuan Liu, Guohua Zhao To further improve the electrochemical performance of a boron-doped diamond (BDD) electrode, a two-dimensional, macroporous, Sb-doped SnO2 film is constructed on BDD to obtain a bifunctional electrode interface (denoted Mp-SnO2/BDD) with an ordered, monolayer, photonic-crystal template using a sol-gel method. SEM images confirm that the SnO2 film consisted of innumerable, uniform, nanosized SnO2 particles and numerous macropores with diameters of 200–300 nm, and some BDD polycrystallites are exposed in those macropores. The microstructure endows Mp-SnO2/BDD with a high oxygen evolution potential (2.23 V), good conductivity (175 O), and excellent electrocatalytic activity. To evaluate the degradation capability, the electrocatalytic oxidation of a high concentration of clofibric acid (CA) is studied in detail. The CA and chemical oxygen demand (COD) removals on Mp-SnO2/BDD are above 90% after 240 min. The degradation rate constant on Mp-SnO2/BDD is 1.6 times that on BDD. Compared with BDD and traditional SnO2/Ti, Mp-SnO2/BDD exhibites a higher instantaneous current efficiency and lower electrochemical energy consumption. In addition, we qualitatively and quantitatively analyze the intermediates in the degradation process and proposed three possible oxidative decomposition pathways for CA. Mp-SnO2/BDD is expected to be a promising anode for organic wastewater treatment.Graphical abstractGraphical abstract for this articleGraphical abstract for this article
       
  • Direct generation of hydroxyl radicals over bismuth oxybromide nanobelts
           with tuned band structure for photocatalytic pollutant degradation under
           visible light irradiation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Chu-Ya Wang, Xing Zhang, Ying-Jie Zhang, Jie-Jie Chen, Gui-Xiang Huang, Jun Jiang, Wei-Kang Wang, Han-Qing Yu Various photocatalysts have been fabricated and tested for the treatment of water and wastewater. As visible-light-driven photocatalysts, bismuth oxybromide nanomaterials have weak responses to visible light and low activities of using photogenerated h+ to produce hydroxyl radicals (OH), both of which are limited by their band structures. Thus, modification of bismuth oxybromide to form an optimized band structure is essential to enhance its photocatalytic activity for environmental applications. In this work, an oxygen-rich bismuth oxybromide nanomaterial, Bi24O31Br10 nanobelt, was fabricated using a solvothermal method, which possessed a narrower band gap and a more positive position of valance band top. As a result, this catalyst exhibited a strong response to visible light and produced large quantities of OH directly via its photogenerated h+, which contributed to the outstanding performance of photocatalysis, as evidenced by the experimental results and density functional theoretical (DFT) calculations. Under visible light irradiation, the Bi24O31Br10 nanobelt exhibited a substantially enhanced photocatalytic efficiency for the degradation of bisphenol A compared to those of Bi24O31Br10 and BiOBr nanosheets. Moreover, this catalyst could resist most interfering ions and was able to treat two types of actual industrial wastewaters efficiently. This work elucidates a new approach to modify photocatalysts and is helpful to expand practical applications of photocatalytic technologies for water and wastewater treatment.Graphical abstractGraphical abstract for this article
       
  • Phase transformation and microwave hydrothermal guided a novel double
           Z-scheme ternary vanadate heterojunction with highly efficient
           photocatalytic performance
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Debin Zeng, Kai Yang, Changlin Yu, Fanyun Chen, XiaoXiao Li, Zhen Wu, Hong Liu Semiconductor-based heteronanostructures with the high carriers-flow steering and high activity and stability in the visible-light-driven multicomponent photocatalytic system have been of great concern due to its long-standing demand in the wide application of environmental protection and energy conversion. However, the construction of ternary-component nanocrystals usally undergos multiple complex steps to restrict its application. In the work, we successfully report the facile design and synthesis of a novel double Z-scheme Zn3(VO4)2/Zn2V2O7/ZnO ternary heteronanostructure system (THS) via self-phase transition with heating on basis of the Zn3(OH)2V2O7·2H2O precursor in a low-cost microwave hydrothermal assistant, which exhibited excellent photocatalytic performances. In this case, the employment of Zn3(OH)2V2O7·2H2O as the heteronanostructure precursor is the key for fabricating the THS material, which not only boosted the interaction with its structure and but also maintained the mesoporous nanosheet structure. It has been proved that Zn3(OH)2V2O7·2H2O firstly lost it H2O and then the partial Zn3(VO4)2 underwent the self-phase transition process to produce Zn2V2O7 and ZnO (Zn3(OH)2V2O7·2H2O → Zn3(VO4)2 → Zn2V2O7 + ZnO), which obtained the double Z-scheme THS. Accordingly, the interfacial-dominated photocatalysis reactivities such as the removal of phenols and dyes were used as ideal experiments to verify the responsibility of the constructed double Z-scheme THS material that was equipped with the narrow band gap, intimate contact interface, the wide visible light absortion and more efficient charge transfer and separation for high visible-light photocatalytic reactivity and stable cycling. PL spectra, radicals trapping experiments and ESR tests confirmed that the nontraditional transport of photoinduced h+ and e− caused by double Z-scheme mechanism played an important role in the efficient removing the target pollutants. Such a synthetic approach maybe render double Z-scheme THS to advance the development for large-scale applications of the hetero-transition metal vanadates.Graphical abstractGraphical abstract for this article
       
  • A honeycomb multilevel structure Bi2O3 with highly efficient catalytic
           activity driven by bias voltage and oxygen defect
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Tong Chen, Qiang Hao, Wenjuan Yang, Chenlang Xie, Daimei Chen, Chao Ma, Wenqing Yao, Yongfa Zhu In this work, we report a bismuth oxide film electrode with oxygen defects and honeycomb multilevel structure prepared by one-step hydrothermal method. The control of raw materials enables to control the thickness and morphology of BiO electrodes. The photoelectrocatalytic of prepared electrodes were tested in various conditions. Under visible light irradiation (λ ≥ 420 nm) and 3 V bias, the sample BiO-2 has the highest photoelectrocatalytic activity, which is 4.95 times higher than the photocatalytic activity and 9.86 times higher than the electrocatalytic activity. The oxygen defects of bismuth oxide were confirmed by EPR and DFT calculation. The morphology and structure of prepared samples were tested by XRD, scanning electronic microscope (SEM), high-resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS). The enhanced photoelectrocatalytic activity is attributed to the proper bias voltage, oxygen defects, and honeycomb multilevel structure. The results of tapping experiments showed that the main active species during the photoelectrocatalytic progress is superoxide radical and the mechanism of the photoelectrocatalysis was proposed.Graphical abstractGraphical abstract for this article
       
  • Oxidation of organic pollutants by peroxymonosulfate activated with
           low-temperature-modified nanodiamonds: Understanding the reaction kinetics
           and mechanism
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Eun-Tae Yun, Gun-Hee Moon, Hongshin Lee, Tae Hwa Jeon, Changha Lee, Wonyong Choi, Jaesang Lee Changes in surface carbon hybridization through high-temperature annealing (>1000 °C) of nanodiamond (ND), i.e., surface graphitization, enable peroxymonosulfate (PMS) activation by ND. Alternatively, this study suggests low-temperature surface modification (500 °C) of ND as an effective strategy for allowing ND to activate PMS. ND calcination in the presence of poly(diallydimethylammonium chloride) (PDDA) and graphene oxide (GO) in an NH3 atmosphere produced binary and ternary nitrogen-doped ND composites (i.e., N-ND/PDDA and N-ND/PDDA/GO). Compared with bare ND, theses surface-modified NDs markedly enhanced organic oxidation associated with PMS activation. In particular, N-ND/PDDA/GO outperformed graphitized ND in terms of PMS activation capacity. Spectroscopic characterization implied that the content of pyridinic N and the N doping level increased with further modification of ND. Oxidation by PMS activated with ND-based materials did not involve radical attack, as methanol did not exhibit a quenching effect, formaldehyde yield was insignificant, conversion of bromide into bromate was negligible, the substrate specificity contradicted sulfate radical (SO4−) reactivity, and no electron paramagnetic resonance spectral features were assignable to SO4− adducts. Impedance spectroscopic analysis indicated a high correlation between PMS activation efficacy and electrical conductivity. Chronoamperometric measurements showed that sequential injection of PMS and 4-chlorophenol caused current generation at electrodes coated with ND-based activators, and the increase in current intensity correlated well with PMS activation capacity. These findings suggest that ND-derived materials facilitated the electron transfer from organics to PMS, resulting in a degradative reaction route not reliant on radical species.Graphical abstractGraphical abstract for this article
       
  • Unveiling the interplay between light-driven CO2 photocatalytic reduction
           and carbonaceous residues decomposition: A case study of Bi2WO6-TiO2
           binanosheets
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Lan Yuan, Kang-Qiang Lu, Fan Zhang, Xianzhi Fu, Yi-Jun Xu One critical issue to which special attention should be paid during the activity evaluation of photocatalytic CO2 reduction is the possible carbonaceous residues on the photocatalyst, which may decompose into CO/CH4, causing overestimation of the activity. In this regard, a contrast test under N2 atmosphere instead of CO2 has been widely employed as one cost-effective approach to confirm whether carbonaceous residues contribute to the carbon-containing products formation. However, this method might otherwise result in underestimation of the activity, according to the case study of as-fabricated Bi2WO6-TiO2 binanosheets (B-T) in this work. Based on integrative studies of B-T sample under N2 and CO2 atmosphere, we for the first time unveil the co-existence of a competition and an interaction relationship between light-driven carbonaceous residues decomposition and photocatalytic CO2 reduction, which further emphasizes the necessity of removing organic residues from photocatalysts and carefully analysing the origin of carbon-containing products to estimate the photocatalytic performance towards CO2 reduction in a more accurate way. Moreover, this work could provide some enlightenment on designing and/or synthesising more efficient photocatalysts for CO2 reduction with high selectivity for CH4 formation, where rational construction of Z-scheme heterostructures is highlighted.Graphical abstractBased on the case study of Bi2WO6-TiO2 binanosheets, we unveil the interplay, i.e., the co-existence of a competition and an interaction relationship between photocatalytic CO2 reduction and light-driven carbonaceous residues decomposition. Moreover, some enlightenment on the future researches in the filed of gas-phase photocatalytic CO2 reduction are proposed.Graphical abstract for this article
       
  • Enhanced visible light catalytic activity of MoS2/TiO2/Ti photocathode by
           hybrid-junction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Chaoqun Cheng, Guohua Liu, Kang Du, Gang Li, Wendong Zhang, Simone Sanna, Yunzhong Chen, Nini Pryds, Kaiying Wang In photoelectrochemical (PEC) water splitting systems, crucial obstacles limiting their performance are poor charge carrier dynamics and high recombination rate of photoexcited electron-hole pairs. Here, we report that this issue can be alleviated by engineering a hybrid-junction that is composed of homo- and hetero- junctions. This strategy is performed by facile hand-spraying MoS2 over the surface of anatase/rutile homo-junction TiO2 film on the Ti substrate to further form a hybrid-junction photocathode. By applying this photocathode into PEC reactor, enhanced catalytic activity is achieved under visible light (AM1.5 illumination of 300 W/m2) with hydrogen evolution reaction (HER) potential of −114 mV versus reversible hydrogen electrode (RHE) at 10 mA/cm2 and long-term stability of more than 10 times improvement comparing to ordinary electrode without the introduction of hybrid-junction. The hybrid-junction that effectively regulates charge separation and transfer pathways is proven to be responsible for the enhanced activity. As a novel exploration, this hybrid-junction system comprising of low-cost, efficient charge separation and transfer, and visible light responsivity offers a new path for relative materials to boost their PEC performance.Graphical abstractGraphical abstract for this article
       
  • Enhanced catalytic activity of electrodeposited Ni-Cu-P toward oxygen
           evolution reaction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Byung Keun Kim, Soo-Kil Kim, Sung Ki Cho, Jae Jeong Kim The slow kinetics of the oxygen evolution reaction (OER) and the high cost of the precious metal catalysts for the OER limit the efficiency and cost-effectiveness of water splitting. In this study, we introduce electrodeposited nickel-copper-phosphorous (NiCuP) as an efficient OER electrocatalyst in alkaline medium. The addition of Cu into the NiP electrocatalyst significantly enhanced the OER activity. Optimization of the electrodeposition conditions revealed that Ni59Cu19P9 in terms of atomic percent exhibited the best activity with a reduced Tafel slope and charge transfer resistance for the OER, compared to NiP. The Ni59Cu19P9 catalyst successfully endured the OER operation at 10 mA/cm2 for up to 30 h while maintaining a Faradaic efficiency of over 99%. The X-ray photoelectron spectroscopy showed that the amount of active Ni hydroxide (NiOOH) species increased with the addition of Cu, which likely contributed to the enhanced of catalytic activity.Graphical abstractGraphical abstract for this article
       
  • The role of surface states during photocurrent switching: Intensity
           modulated photocurrent spectroscopy analysis of BiVO4 photoelectrodes
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Manuel Antuch, Pierre Millet, Akihide Iwase, Akihiko Kudo Intriguing photo-electrochemical characteristics of BiVO4 photoelectrodes studied in pH-neutral aqueous solutions are reported herein. Indeed, we have observed photocurrent polarity switching, as put in evidence by cyclic voltammetry under chopped illumination conditions. Such unusual behavior was analyzed in detail using Intensity Modulated Photocurrent Spectroscopy (IMPS). At potentials where positive photocurrent was observed, the expected shape of IMPS was recorded, starting in quadrant (IV) at high-frequency (HF) and reaching quadrant (I) at low-frequency (LF) with two well defined semicircles. Surprisingly, in the negative photocurrent region, IMPS started in quadrant (II) at HF and ended in quadrant (III) at LF. Such highly infrequent features were interpreted here as the rotation of the IMPS spectra around the origin of the plot, due to the sign switch of the photocurrent. A model that takes into account the existence of in-band energy states at the surface of BiVO4 has been used in order to account for the experimental results. It was found that (i) the surface state capacitance; (ii) the relaxation time constant associated to surface states; and (iii) the density of in-gap surface states, were all showing a well-marked maximum in the nearby value of the switch potential. This suggests that surface states are more influent in the nearby where photocurrent switch occurs.Graphical abstractGraphical abstract for this article
       
  • In-situ electrosynthesis of hydrogen peroxide and wastewater treatment
           application: A novel strategy for graphite felt activation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhangweihao Pan, Kun Wang, Yi Wang, Panagiotis Tsiakaras, Shuqin Song Electrochemical synthesis of hydrogen peroxide (H2O2) through O2 electroreduction is an attractive alternative to the currently used anthraquinone process, and highly desirable for green chemical industries and environmental remediation. However, it remains a great challenge to develop cost-effective and durable electrocatalysts. Hence, rational strategy for developing electrocatalyst materials to achieve highly efficient 2e− pathway oxygen reduction reaction (ORR) electrocatalysis is extremely important for in situ electrochemical synthesis of H2O2.In the present work, an economical activated graphite felt (AGF) material, following a simple and low-cost gaseous acetic acid activation method, is developed. With this activation process, the electrochemical performance of the AGF shows a great promotion for H2O2 production rate. Compared with raw graphite felt (RGF) material, the yield of H2O2 achieved on AGF is enhanced by several folds. The enhanced performance might be attributed to its specific pore structure, high content of defects and transformation of surface chemical bonds, which derives from the activation with gaseous acetic acid at high temperature.It is found that the factors responsible for the remarkable electrocatalytic performance of AGF1100 are: 1) the special pore structure, which offers large area for reaction, obtained through gaseous acetic acid activation process at high temperature; 2) high content of sp3C bonds, defects, and oxygen-containing functional groups, which can act as active sites for oxygen adsorption or reduction during the electrocatalytic process.Graphical abstractGraphical abstract for this article
       
  • PtSn nanoparticles supported on titanium carbonitride for the ethanol
           oxidation reaction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): M. Roca-Ayats, O. Guillén-Villafuerte, G. García, M. Soler-Vicedo, E. Pastor, M.V. Martínez-Huerta The effect of titanium carbonitride (TiCN) as a new support for platinum-tin nanoparticulated catalysts for the ethanol oxidation reaction (EOR) in acid medium was evaluated. For that purpose, two platinum-tin catalysts supported on TiCN and carbon black (Vulcan XC-72R) were synthesized following the ethylene glycol method. XRD, TEM, ICP-OES and XPS techniques revealed that both catalysts exhibit similar physicochemical properties. However, the EOR and the CO tolerance were enhanced at the catalyst supported on TiCN. In situ Fourier transform infrared spectroscopy (FTIRS) and differential electrochemical mass spectrometry (DEMS) were used in order to get more information on the reaction mechanism and product selectivity. Main results indicate an improvement of the CO oxidation reaction by facile water dissociation on PtSn/TiCN, and elevated current output during the EOR on PtSn/TiCN since the acetaldehyde path is the favored, meanwhile the CO and acetic acid pathways are suppressed at this catalytic material. Significant differences were observed between both catalysts, indicating an extraordinary impact of the support in the catalytic performance.Graphical abstractGraphical abstract for this article
       
  • Activating BaTaO2N by Ca modifications and cobalt oxide for visible light
           photocatalytic water oxidation reactions
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Shunhang Wei, Guan Zhang, Xiaoxiang Xu Despite a strong visible light absorbance as far as 660 nm, BaTaO2N generally exhibits a poor photocatalytic activity for water splitting under ordinary conditions. High levels of defects as well as photocatalytic self-decomposition are likely the major causes for this incommensuration. In this work, we have modified BaTaO2N by introducing Ca to the structure, i.e. BaCax/3Ta1-x/3O2+yN1-y (0 ≤ x, y ≤ 1). A number of important properties such as band gap, defects levels and nitrogen content can be tuned by varying the amounts of Ca in the structure. In particular, defects such as Ta4+ species can be effectively suppressed by Ca incorporation. More importantly, photocatalytic activity for water oxidation has been significantly enhanced and stability against photocatalytic self-decomposition has also been largely improved in Ca modified BaTaO2N. An apparent quantum efficiency as high as ∼ 2.1% at 420 ± 20 nm has been achieved and stands as the highest AQE for BaTaO2N reported to date. Photoelectrochemical (PEC) analysis reveals a much higher photocurrent in Ca modified BaTaO2N and identifies the role of cocatalyst CoOz in reducing charge transfer resistance for water oxidation reactions. Open-circuit voltage decay (OCVD) measurements further confirm the improved charge separation conditions in Ca modified BaTaO2N and functions of cocatalyst CoOz in collecting and storing photo-generated holes. The optimal loading point for cocatalyst CoOz corresponds to the one that gives the highest capacity for hole storage.Graphical abstractA number of important properties of BaTaO2N such as band gap, defects level, nitrogen content etc. can be controlled by Ca modifications. In particular, defects such as Ta4+ species in BaTaO2N are suppressed in the presence of Ca which leads to a substantial improvement on photocatalytic water oxidation reactions.Graphical abstract for this article
       
  • Efficient visible-light-driven depolymerization of oxidized lignin to
           aromatics catalyzed by an iridium complex immobilized on mesocellular
           silica foams
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhongkai Hao, Shuyuan Li, Jiarong Sun, Song Li, Fang Zhang A novel Ir(ppy)2(bpy) complex-containing mesoporous cellular silica foams (Ir(ppy)2(bpy)-MCFs) was prepared by a facile thiol-ene click reaction between the prefabricated thiol-functionalized mesoporous cellular silica foams and vinyl-tagged [Ir(ppy)2(bpy)]PF6 complex. The elaborate Ir(ppy)2(bpy)-MCFs material possessed the large surface area (355 cm2/g), open foam-like mesoporous structure with 30 nm cell pore size and 3.0 nm window pore size. Importantly, it had the well-defined molecular configuration of Ir(ppy)2(bpy) active species. As expected, it exhibited excellent catalytic reactivity and selectivity in the visible-light-driven reductive depolymerization of oxidized lignin β-O-4 model compounds including p-hydroxyphenyl (H)-, guaiacyl (G)- and syringyl (S)-type units under the mild conditions. Meanwhile, it showed the comparable catalytic efficiency with the corresponding homogeneous [Ir(ppy)2(bpy)]PF6 catalyst. These high catalytic performances could be attributed to aerogel-like three-dimensional pore structure and high visible-light transparency, which efficiently decreased the mass transfer resistance and the photon propagation hindrance. Furthermore, it could be easily recycled and reused at least six times without the remarkable loss of catalytic activity.Graphical abstractGraphical abstract for this article
       
  • Regeneration of NiAl2O4 spinel type catalysts used in the reforming of raw
           bio-oil
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Aingeru Remiro, Aitor Arandia, Lide Oar-Arteta, Javier Bilbao, Ana G. Gayubo The regenerability of Ni catalysts in reforming reactions is a key factor for process viability. Accordingly, this study addresses the regeneration of two spinel NiAl2O4 type catalysts by reaction-regeneration cycles in the oxidative steam reforming (OSR) of raw bio-oil. The spinel type catalysts were prepared by different methods including a supported Ni/La2O3-αAl2O3 catalyst and a bulk NiAl2O4 catalyst. The experimental set-up consists of two units connected in series for i) the thermal treatment of bio-oil at 500 °C, in order to control the deposition of pyrolytic lignin, followed by; ii) the oxidative steam reforming (OSR) of the remaining oxygenates in a fluidized bed catalytic reactor. The conditions in the OSR reaction step were: 700 °C; oxygen/steam/carbon ratio (O/S/C), 0.34/6/1; space time, 0.75 gcatalysth/gbio-oil (for supported catalyst) and 0.15 gcatalysth/gbio-oil (for bulk catalyst). Three different strategies have been studied in the regeneration step by coke combustion, including the in situ regeneration inside the reactor at 650 °C and 850 °C, and the ex situ regeneration in an external oven at 850 °C, for 4 h in all the cases. The behavior of the fresh and regenerated catalysts has been explained according to their metallic properties, determined by different characterization techniques (temperature programmed reduction (TPR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electronic microscopy (TEM)). According to these results, the combustion ex situ of the catalyst at 850 °C is able to completely regenerate the bulk catalyst, since these regeneration conditions lead to the total recovery of the NiAl2O4 spinel phase together with negligible loss of Ni on the surface in the catalyst. These novel results are crucial for future industrial implementation of the process.Graphical abstractGraphical abstract for this article
       
  • Copper-nickel catalysts from hydrotalcite precursors: The performance in
           NO reduction by CO
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Daniel Lopes, Fatima Zotin, Luz Amparo Palacio In the present work, catalysts based on copper and nickel and obtained from hydrotalcite like-compounds were evaluated in the NO reduction by CO in order to analyze the activity and yield to N2 and N2O. The co-precipitation method was used to obtain catalyst precursors with variable (y = Cu/(Cu + Ni)) molar ratios values (y = 0, 0.3, 0.5, 0.7 and 1). The use of terephthalate as a compensation anion was a novelty in this series of precursors. The formation of layered compound was observed at y values smaller than or equal to 0.7. The X-ray absorption spectroscopy analysis showed that the Cu-catalysts obtained from the calcination of the precursor at 600 °C have only Cu2+ species, and Cu+ and Cu° species were found throughout the reaction as observed by in situ XANES. However, even during pretreatment at 500 °C under helium flow, copper reduced species were observed. According to TPR results, the introduction of a second metal decreased the reduction temperature of the monometallic catalysts. An easier reduction of copper oxide over nickel is also clear. Cu content, calcination temperature, compensation anion of the hydrotalcite and a pre-reduction of the catalysts significantly impact on the activity and selectivity of the catalysts.Graphical abstractGraphical abstract for this article
       
  • Polymeric graphitic carbon nitride nanosheet-coated amorphous carbon
           supports for enhanced fuel cell electrode performance and stability
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): In Hyuk Lee, Jinwon Cho, Keun Hwa Chae, Min Kyung Cho, Juhae Jung, Jongin Cho, Hyun Jin Lee, Hyung Chul Ham, Jin Young Kim Carbon blacks, which consist of the assemblies of small graphene clusters having a spherical concentric packing structure, are amorphous and have widely been used as catalyst supports for proton exchange membrane fuel cell (PEMFC) electrodes. However, poor electrochemical corrosion resistance during extended use and repeated cyclic operation of PEMFCs shortens their practical device lifetime; surface defects, such as nanosized disordered domains, have been established as the most influential factors. Herein, we coupled polymeric graphitic carbon nitride (pg-CN) with amorphous carbon black (a-CB) in a core@shell structure to produce an electrochemically efficient and stable electrocatalyst support. Our protocol allowed for the simultaneous optimization of uniformly thin graphitic shell structures for electrochemical corrosion stability and nitrogen-enriched functionalities on the carbon surfaces for electrocatalyst (e.g., platinum) nucleation. The newly prepared a-CB@pg-CNs enhanced the stable fuel cell devices operation and remained invariant even at high potential (1.2–1.7 V). Significantly, when used for constructing the PEMFC electrode, a-CB@pg-CN support-based Pt catalyst electrodes outperformed and exhibited superior stability over state-of-the-art commercial a-CB-based counterparts. Experimental observations and density functional theory (DFT) calculations revealed that the unusual electrocatalytic properties of as-prepared a-CB@pg-CNs originated from an intrinsic chemical and electronic coupling that synergistically reduced electrochemical corrosion kinetics and promoted catalyst–support interactions.Graphical abstractGraphical abstract for this article
       
  • Pt@Cu2O/WO3 composite photocatalyst for enhanced photocatalytic water
           oxidation performance
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Huihua Gong, Yifeng Zhang, Yue Cao, Maolan Luo, Zhicheng Feng, Wenbin Yang, Kewei Liu, Hongmei Cao, Hongjian Yan In this study, Pt@Cu2O/WO3 composite photocatalyst was constructed via coupling Cu2O onto the edged (200) and (020) facets of square-like WO3 nanoplates and followed by photodeposition of Pt onto Cu2O. The remarkably enhanced photocatalytic water oxidation activity over such assembled Pt@Cu2O/WO3 composite photocatalyst was observed. The superior photocatalytic performance can be attributed to intrinsic nature of charge separation between different facets of square-like WO3, highly efficient WO3-to-Cu2O electron transfer occurring at the intimate contact interface between WO3 and Cu2O, and Pt as reduction cocatalyst. This work will provide new deep insights into the design of crystal-based Z-scheme heterostructure photocatalysts by facet-preferentially coupling one semiconductor with another.Graphical abstractGraphical abstract for this article
       
  • Bi quantum dots obtained via in situ photodeposition method as a new
           photocatalytic CO2 reduction cocatalyst instead of noble metals: Borrowing
           redox conversion between Bi2O3 and Bi
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Guihua Yang, Wenkang Miao, Zhimin Yuan, Zaiyong Jiang, Baibiao Huang, Peng Wang, Jiachuan Chen Metal Bi is applied as the cocatalyst instead of noble metals, for the first time, in photocatalytic CO2 reduction and exhibits significant increase in CO yield compared to that of pristine photocatalyst, about 4.8 times. In situ photodeposition method is used to prepare metal Bi. Surprisingly, the average size of metal Bi obtained is ca. 5 nm and can be considered as quantum dots level, which is very difficult to be realized for noble metals via in situ photodeposition. Unfortunately, such small Bi is unstable in air, making it very difficult for the preservation. Another fortunate phenomenon is discovered, the unstable metal Bi can be stored via using the form of Bi/Bi2O3 quantum dots (Bi2O3 is main body of white Bi/Bi2O3 composites). When carried out the photocatalytic CO2 reduction, the white Bi/Bi2O3 can be easily transformed into grey Bi/Bi2O3 composites (the main body of grey Bi/Bi2O3 composites is metal Bi) to improve the photocatalytic CO2 reduction rate. This reason is that CB level of Bi2O3 quantum dots has shifted to a more negative position due to quantum confinement effect compared to the standard redox potential of Bi2O3/Bi (0.37 eV), leading to Bi2O3 easily to be reduced to metal Bi under the effect of photogenerated electrons derived from TiO2. This work demonstrated the mutual conversion between storage and utilization may offer an attractive approach for the application of unstable quantum dot materials or single atom materials.Graphical abstractGraphical abstract for this article
       
  • Vanadium disulfide decorated graphitic carbon nitride for super-efficient
           solar-driven hydrogen evolution
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Mengmeng Shao, Yangfan Shao, Shengjie Ding, Jingwei Wang, Jinchen Xu, Yuanju Qu, Xiongwei Zhong, Xinman Chen, Weng Fai Ip, Ning Wang, Baomin Xu, Xingqiang Shi, Xuesen Wang, Hui Pan Highly efficient, earth-abundant, and low-cost photocatalysts are widely pursued for solar-driven hydrogen generation from water. Herein, we first report vanadium disulfide (VS2) with high hydrogen evolution reaction (HER) activity both in basal and edges to be the co-catalyst of graphitic carbon nitride (g-C3N4) for ultrahigh solar-driven hydrogen production. VS2-decorated g-C3N4 shows an impressing photocatalytic hydrogen evolution with a rate of 87.4 μmol/h, 26 times higher than pristine g-C3N4. Our combined experimental and computational studies reveal that the excellent efficiency of the composite is attributed to: (1) effective electron-hole separation and electron transfer from g-C3N4 to VS2, resulting from the optimal band alignment between VS2 and g-C3N4 and metallic characteristic of VS2; (2) fast hydrogen generation on the surface due to the high surface area and excellent HER activity of VS2. Our findings demonstrate that VS2/g-C3N4 may be applicable in solar-driven water splitting, and the design principle can be applied to search for novel photocatalysts.Graphical abstractThe VS2/g-C3N4 shows a super high photocatalytic performance in water splitting, which is mainly contributed to the efficient separation of electron-hole pair, fast transportation of carriers, enhanced redox reaction, and high surface area.Graphical abstract for this article
       
  • Hierarchical photocatalyst of In2S3 on exfoliated MoS2 nanosheets for
           enhanced visible-light-driven Aza-Henry reaction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhen Li, Zhou Zhou, Jingwen Ma, Yang Li, Wenchao Peng, Guoliang Zhang, Fengbao Zhang, Xiaobin Fan Exploration of appropriate photocatalysts for visible-light-driven organic synthesis is of great importance. Here we design and construct a two-dimensional hierarchical In2S3/MoS2 composite as an excellent and reusable photocatalyst for Aza-Henry reaction. The dahlia-flower-like In2S3 nanostructures are homogeneously grown on both sides of the two-dimensional MoS2 nanosheets via a hydrothermal reaction. The as-prepared two-dimensional hierarchical In2S3/MoS2 composite exhibits higher photocatalytic performance than pure In2S3. The hierarchical heterostructure can enhance the light absorption in the visible region, facilitate the separation of the photo-induced electron–hole pairs, offer rich active sites for photoredox reactions and promote the generation and migration of the O2‐ and h+. Profiting from these compositional and structural features, the two-dimensional hierarchical In2S3/MoS2 composite shows remarkably enhanced photocatalytic performance and good stability.Graphical abstractGraphical abstract for this article
       
  • Highly efficient photocatalytic degradation of naphthalene by
           Co3O4/Bi2O2CO3 under visible light: A novel p–n heterojunction
           nanocomposite with nanocrystals/lotus-leaf-like nanosheets structure
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Yang Guo, Yuxuan Dai, Wei Zhao, Hui Li, Bin Xu, Cheng Sun Exploring visible-light-driven nanomaterials to substitute crucial bulk composite under UV-light is of great significance in photodegradation of hardly-decomposed persistent pollutants in the environment. Herein, the novel p–n heterojunction photocatalyst p-Co3O4/n-Bi2O2CO3 with zero dimensional(0D)-two dimensional(2D)nanocrystals/lotus-leaf-like nanosheets structure was successfully obtained for the first time via a facile hydrothermal method, in which the density of Co3O4 loaded on the Bi2O2CO3 was easily tuned by the concentration of Co3O4 precursor in the solution. The outstanding feature of the photocatalyst is that the resultant hybrid nanocomposite exemplified the p–n heterojunction visible-light materials for degrading the naphthalene efficiently and effectively. As the presence of Co3O4 and the synergistic interactions of p–n heterojunction, the recombination of photogenerated charge carriers has been suppressed, and the visible light absorbance has been improved. Consequently, the visible light photocatalytic performance has been enhanced. The p-Co3O4/n-Bi2O2CO3 sample with Co3O4/Bi2O2CO3 mass ratio 1:6 exhibited the highest photocatalytic activities among all the as-prepared samples with the degradation efficiency of about 91.02% naphthalene in 150 min. The photocatalytic mechanism of p-Co3O4/n- Bi2O2CO3 for degrading naphthalene was analyzed based on the semiconductor energy band theory and the formation of an internal electrostatic field. The probable degradation intermediates and products of naphthalene were identified by GCMS. The proposed photodegradation pathways of naphthalene were described by combining the frontier electron density calculation and GCMS results.Graphical abstractGraphical abstract for this article
       
  • Local dynamics of copper active sites in zeolite catalysts for selective
           catalytic reduction of NOx with NH3
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Peirong Chen, Abhishek Khetan, Magdalena Jabłońska, Johannes Simböck, Martin Muhler, Regina Palkovits, Heinz Pitsch, Ulrich Simon In Cu-zeolite based selective catalytic reduction of NOx with NH3 (NH3-SCR), Cu species (in particular CuI) solvated by NH3 molecules are predicted theoretically to be highly mobile with their mobility being decisive for the NH3-SCR reactivity at low temperatures (
       
  • Study of Ag promoted Fe2O3@CeO2 as superior soot oxidation catalysts: The
           role of Fe2O3 crystal plane and tandem oxygen delivery
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Houlin Wang, Baofang Jin, Haobo Wang, Ningning Ma, Wei Liu, Duan Weng, Xiaodong Wu, Shuang Liu In this work, model α-Fe2O3 catalysts with different morphologies were synthesized to investigate crystal plane effects on soot oxidation. The results revealed that the electron-rich state of Fe2O3 {113} planes conferred them more surface Ox− and thus better catalytic performance than the {014} and {012} planes. Surface grafting of a polycrystalline CeO2 layer onto Fe2O3 gave rise to Fe2O3@CeO2 catalysts with drastically increased oxygen utilization. More importantly, by loading Ag nano-particles on the surface of Fe2O3@CeO2, a tandem oxygen delivery route was opened, resulting in strong Ox- generation/regeneration ability and superior low temperature soot oxidation activity. These Ag/Fe2O3@CeO2 catalysts overwhelmed the nano-cubic Ag/CeO2 in both catalyst cost and activity, making them very promising for application in catalyzed gasoline particulate filters (CGPFs).Graphical abstractGraphical abstract for this article
       
  • Dynamic modification of pore opening of SAPO-34 by adsorbed surface
           methoxy species during induction of catalytic methanol-to-olefins
           reactions
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): B.T.W. Lo, L. Ye, G.G.Z. Chang, K. Purchase, S. Day, C.C. Tang, D. Mei, S.C.E. Tsang Here, we report that the 8-membered ring pore opening of SAPO-34 zeolite can be significantly modified by an adsorbed surface methoxy species (SMS) during the induction period of the catalytic methanol-to-olefins process, which offers molecular sieving properties. It is due to the physical obstruction caused by the surface methoxy species, which also modifies the adsorption properties of other hydrocarbons. Synchrotron X-ray powder diffraction and Rietveld refinement reveal that the SMS is dynamically created from methanol dehydration on a Brønsted acid site near the narrow pore windows. Thus, industrially desirable lower olefins such as ethylene and propylene can be favourably made at the expense of higher olefins. The crystal structures and fundamental understanding in altering the olefin selectivity during induction may allow rational optimisation in catalytic performance under complex fluidised conditions. This work offers additional but alternative insights to the ‘dual cycle’ mechanistic study of the catalytic methanol-to-olefins process.Graphical abstractGraphical abstract for this article
       
  • Highly dispersed Rh-, Pt-, Ru/Ce0.75Zr0.25O2–δ catalysts prepared by
           sorption-hydrolytic deposition for diesel fuel reforming to syngas
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): T.B. Shoynkhorova, P.A. Simonov, D.I. Potemkin, P.V. Snytnikov, V.D. Belyaev, A.V. Ishchenko, D.A. Svintsitskiy, V.A. Sobyanin Three noble metal catalysts (Rh-, Pt-, Ru/Ce0.75Zr0.25O2–δ) for reforming of hydrocarbons were studied in steam and autothermal process conditions. Each catalyst was prepared by sorption-hydrolytic deposition with a metal loading of 0.1 mmol/g. The main idea of this technical approach was to form a solution of “metal complex + alkaline agent” that was metastable at given conditions (temperature, concentrations) with respect to homogeneous metal hydroxide precipitation, due to the kinetic inertness of the metal complexes for ligand exchange. As the support surface accelerated heterogeneous nucleation and growth of metal hydroxide particles, addition of the support to the reagent mixture initiated the hydrolysis which led to uniform depositing of 1–2 nm metal particles over the support surface. The Rh-based catalyst synthesized surpassed the Ru- and Pt-based catalysts in activity and stability in that under the experimental conditions, complete n-hexadecane conversion and equilibrium reformate product distribution were observed for 1-wt. % Rh/Ce0.75Zr0.25O2–δ for 17 h. This catalyst also showed competitive performance in autothermal reforming of diesel fuel providing stable operation for 9 h.Graphical abstractGraphical abstract for this article
       
  • Anchoring ultrafine Pt electrocatalysts on TiO2-C via photochemical
           strategy to enhance the stability and efficiency for oxygen reduction
           reaction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Jingyu Wang, Min Xu, Jianquan Zhao, Huaifang Fang, Qingzhu Huang, Weiping Xiao, Tao Li, Deli Wang The activity and stability of Pt electrocatalysts are crucial issues for energy conversion systems involving oxygen reduction reaction (ORR). In this work, the ultrafine Pt nanoparticles were in situ reduced by the photogenerated electrons on TiO2 surface so that most of them selectively anchored around the TiO2 nanocrystals. The presence of well-dispersed TiO2 on carbon surface strengthened the metal-support interaction, giving rise to the improved ORR catalytic activity with ∼49 mV positive shift of half-wave potential as compared to commercial 20 wt% Pt/C. More importantly, the Pt/TiO2-C catalysts exhibited a more durable performance after 10,000 cycles in terms of the decrease in electrochemical surface area (0.8%) and mass activity (0.9%), much lower than those of Pt/C (10.2% and 33.3%). The high-temperature durability test also revealed a much higher retention of ORR activity. The results demonstrated that anchoring Pt on well-dispersed TiO2-decorated carbon would be an effective strategy to enhance the ORR performance by strong metal-support interaction, which facilitated the electron transfer during catalytic reactions as well as prevented Pt aggregation during durability test.Graphical abstractGraphical abstract for this article
       
  • Alkali and earth alkali modified CuOx/SiO2 catalysts for propylene partial
           oxidation: What determines the selectivity'
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Janvit Teržan, Petar Djinović, Janez Zavašnik, Iztok Arčon, Gregor Žerjav, Matjaž Spreitzer, Albin Pintar In this work, CuOx/SiO2 catalysts were investigated in the propylene partial oxidation reaction. Ordered mesoporous silica (KIT-6) was used to deposit 1–10 wt. % copper and subsequently modified with Na, K and Ca. The synthesized materials were characterized by N2 physisorption, XRD, TEM-EDS, CO2-TPD, operando UV/Vis DRS, operando XANES and pyridine DRIFT spectroscopy. Regardless of the CuOx loading, catalyst deactivation was observed during propylene oxidation reaction in non-modified catalysts, which was related to sintering of oligomeric [Cu-O-Cu]n species. Sintering of CuOx is strongly promoted under a reducing propylene atmosphere and related to the presence of Cu+1. The resulting bulk CuOx promotes acrolein selectivity. We produced modified catalysts with finely dispersed alkali metal cations, associated with the subnanometer CuOx phase, resulting in a greatly stabilized morphology and catalytic activity. Operando XANES analysis revealed that a substantial fraction of Cu2+ is transformed to Cu+ during the propylene oxidation reaction (52–68%, depending on the modifying atom). Also, the dynamics of reaching the quasi steady oxidation state differ strongly. The kinetics of oxygen abstraction and replenishment are substantially different, indicative of modified chemistry of the nucleophilic oxygen species, present in 5CuNa catalyst in contrast to others (5Cu and 5CuCa). We propose that Cu+ is not crucial for PO formation. Instead the electropositive Na+ and K+ decrease the nucleophilic strength of oxygen in CuOx, by attracting its electrons. Consequently, the catalytic action of oxygen changes from oxidative attack on the allylic hydrogen to oxygen insertion into the CC bond of propylene. This results in a noticeable selectivity shift from acrolein to propylene oxide. The effect of calcium on decreasing the nucleophilic character of O species in CuOx is negated by charge compensation by strongly adsorbed hydroxyl groups and Ca modification for PO selectivity is inefficient. Additionally we found, that further oxidation of propylene oxide is, most likely, the main factor determining high selectivity for COx products. The alkali modification which increases the PO selectivity does not function via elimination of LAS, but exclusively through attenuation of nucleophilic character of oxygen species.Graphical abstractGraphical abstract for this article
       
  • Catalytic reduction of bromate over catalysts based on Pd nanoparticles
           synthesized via water-in-oil microemulsion
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Ana M. Perez-Coronado, Olivia Salome G.P. Soares, Luisa Calvo, Juan J. Rodriguez, Miguel A. Gilarranz, Manuel Fernado R. Pereira Supported Pd nanoparticles (NPs) synthesized via water-in-oil (w/o) microemulsion using the water/AOT/isooctane system were used as catalysts in the bromate reduction. In order to study the influence of the support on the catalytic activity, Pd NPs were immobilized on activated carbon (AC), multi-walled carbon nanotubes (CNT) and TiO2. Different thermal treatments in air and nitrogen were carried out in 473–673 K range to modify the supports and also to remove AOT from supported nanoparticles. The immobilization of Pd NPs on TiO2 led to higher activity than the immobilization on the carbon-based supports. Thermal treatment of the catalysts at 673 K in air removed successfully AOT and its decomposition fragments, leading to a significant increase in activity. After removal of AOT, the experiments with catalysts prepared with Pd NPs of different size and supported on TiO2 did not show significant differences in activity. Therefore, no evidence of structure sensitiveness was found.Graphical abstractGraphical abstract for this article
       
  • Site-selective Pt dewetting on WO3-coated TiO2 nanotube arrays: An
           electron transfer cascade-based H2 evolution photocatalyst
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Davide Spanu, Sandro Recchia, Shiva Mohajernia, Patrik Schmuki, Marco Altomare Among several parameters that affect the yield of a photocatalytic process mediated by a metal oxide semiconductor, key is the efficient separation and transfer of photo-generated charge carriers. To overcome kinetic limitations and enable charge transfer, an effective strategy is to decorate the photocatalyst surface with cocatalytic nanoparticles of either a second semiconductor metal oxide or a noble metal. Nevertheless, classical deposition techniques based on powder technology approaches lead to randomly placed cocatalytic nanoparticles at the photocatalytic surface. The poor control over cocatalyst placement can drastically hamper the photocatalytic efficiencies, and can also prevent a full understanding of the charge carrier dynamics and photocatalytic mechanism. Here we investigate a highly defined charge separation platform for photocatalytic H2 evolution based on a Pt-WO3-TiO2 “stacked” structure constructed on anodically grown TiO2 nanotube arrays. Key is the formation of a site-selective and sequential W and Pt metal sputter-decoration only at the mouth of highly-ordered TiO2 nanotubes. After placing the W-Pt bilayer at the nanotubes mouth, a suitable thermal treatment forms a WO3 layer atop the nanotubes while the Pt film undergoes solid state dewetting into 2–6 nm-sized Pt nanoparticles. These structures show strongly improved photocatalytic H2 evolution efficiency compared to any other single-cocatalyst system (Pt-TiO2 and WO3-TiO2) and pristine TiO2 nanotubes. The photocatalytic activity improvement is ascribed to an enhanced charge carrier separation mechanism enabled by the well-defined TiO2-WO3-Pt architecture that provides swift electron transfer through WO3 and towards Pt for H2 evolution.Graphical abstractGraphical abstract for this article
       
  • The investigation of the role of basic lanthanum (La) species on the
           improvement of catalytic activity and stability of HZSM-5 material for
           eliminating methanethiol-(CH3SH)
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Jichang Lu, Husheng Hao, Liming Zhang, Zhizhi Xu, Liping Zhong, Yutong Zhao, Dedong He, Jiangping Liu, Dingkai Chen, Hongping Pu, Sufang He, Yongming Luo Lanthanum (La)-doped HZSM-5 and HZSM-5 catalysts were prepared to investigate the natural roles of La addition on the catalytic performance of HZSM-5 for decomposing methanethiol (CH3SH). Compared to HZSM-5, the incorporation of La species into HZSM-5 catalyst not only decreased the intrinsic activation energy (from 51.4 kJ/mol to 40.6 kJ/mol) but also largely improved the stability. Based on the characterizations of X-ray diffraction pattern (XRD), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of carbon dioxide (CO2-TPD), temperature-programmed desorption of ammonia (NH3-TPD), and temperature programmed desorption of CH3SH (CH3SH-TPD), the promotional role of La species on the catalytic activity was demonstrated to be the contribution of the surface active oxygen species within lanthanum oxy-carbonates composites, which not only might act as new active sites for converting CH3SH into CO2 but also could decrease the activation temperature for the dehydrogenation of CH3SH into intermediate, dimethyl sulfide (CH3SCH3). The enhanced stability of La doped HZSM-5 was attributed to the synergistic effect of the decrease in the strong acid sites as well as the formed CO2 and surface lanthanum oxy-carbonates layer. The rapid deactivation of HZSM-5 was due to the formation of deposited coke irrespective of deposited sulfur species. The nature, amount and type of deposited coke were investigated in detail via the characterization of FTIR, Raman spectroscopy, temperature programmed oxidation of oxygen (O2-TPO), thermogravmetric analysis (TGA). A facile and rapid regeneration method was used to regenerate spent La doped HZSM-5 and no significant deactivation was observed even after three cycles of deactivation-regeneration.Graphical abstractGraphical abstract for this article
       
  • Electron blocking and hole extraction by a dual-function layer for
           hematite with enhanced photoelectrocatalytic performance
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Shuai Chen, Jinhua Li, Jing Bai, Ligang Xia, Yan Zhang, Linsen Li, Qunjie Xu, Baoxue Zhou To address the poor charge transport performance and severe surface combination of Hematite (Fe2O3), surface modification of electron blocking layer with a more negative conduction band than Fe2O3 have gradually received attention, which could prevent excess electrons escaping from Fe2O3 to the electrode surface. However, the electron blocking process is often accompanied by the similar hole blocking effect, resulting in severe secondary interface recombination. Here, we design a ZnFe2O4 active layer between Fe2O3 substrate and ZnO electron blocking layer to avoid the interface stacking phenomenon of photogenerated carriers. The photogenerated holes can be promptly extracted from valence band of Fe2O3 to the photoanode surface and the electrons can be smoothly delivered from Fe2O3 and FTO, avoiding the carriers interface accumulation. The optimized Fe2O3/ZnFe2O4/ZnO achieved a significant enhancement in photocurrent of 0.805 mA/ cm2 at 1.23 V vs. RHE when compared to the pristine Fe2O3 value of 0.12 mA/ cm2, Fe2O3/ZnFe2O4 of 0.58 mA/ cm2 and Fe2O3/ZnO of 0.38 mA/ cm2, increased by 670%, 140% and 210%, respectively. Meanwhile, the degradation rate constant is remarkably increased by 483%, 144% and 191% for treating a typical organic pollutant of methyl orange. Our finding emphasizes the importance of electron blocking layer and holes extraction layer on overall photogenerated carriers’ transfer, in achieving a hematite based photoanode with high PEC performance. These results provide a new strategy toward the surface design of more efficient PEC water splitting and organic degradation photoanode.Graphical abstractGraphical abstract for this article
       
  • Defects induced efficient overall water splitting on a carbon-based
           metal-free photocatalyst
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Cheng Zhu, Mengmeng Zhu, Yue Sun, Yunjie Zhou, Hui Huang, Yeshayahu Lifshitz, Shuit-Tong Lee, Jun Zhong, Yang Liu, Zhenhui Kang Hydrogen production from overall water splitting by photocatalyst is an ultimate clean and renewable energy strategy. Recent developments show that carbon based materials are considerable photocatalysts for overall water splitting under visible light because of their high activity, high stability, low-cost, easy fabrication and structural diversity. However, it still lacks a systematic study and deep understanding on the working mechanism of the carbon based photocatalysts. Herein, we show the fabrication of a carbon photocatalyst with abundant carbon defects created by removing the nitrogen atoms from a N-doped precursor. The active defects bond with water molecules during the photocatalytic reaction, which then work as oxidation sites for O2 generation. We also demonstrate an accessible strategy to produce more defects to observably enhance the photocatalytic activity (around 10 times) as well as to select between the 2-electron/2-electron and the 4-electron pathway water splitting. The synthesized photocatalyst is efficient in photocatalytic visible-light overall water splitting with an optimum H2 and O2 production of 2.54 and 1.25 μmol h−1, respectively. Moreover, the quantum efficiency and solar to hydrogen (STH) efficiency were measured to be 2.04% for wavelength λ = 420 ± 20 nm and 0.1% using AM 1.5 G, respectively.Graphical abstractAn efficient carbon-based metal-free photocatalyst with abundant carbon defects can split water under visible light irradiation.Graphical abstract for this article
       
  • Efficient n+p-Si photocathodes for solar H2 production catalyzed by Co-W-S
           and stabilized by Ti buffer layer
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Ronglei Fan, Guanping Huang, Yongjie Wang, Zetian Mi, Mingrong Shen Photoelectrochemical (PEC) water splitting is regarded as a promising route to produce sustainable hydrogen fuel using sunlight and water as sole inputs. Si is one of the most promising potential materials for PEC photocathode, while developing highly active non-precious catalysts and stable semiconductor/catalyst interface is critical to bring solar water splitting into reality. Herein, we reported a cheap and effective strategy based on a wet chemical method to integrate WS2 and Co-doped WS2 (Co-W-S) onto n+p-Si as noble metal−free catalysts for H2 production. Co-W-S/n+p-Si photocathode exhibited much better PEC performance, resulting from the Co-W-S catalyst which has more electrochemically active sites and better electrical conductivity. A thin Ti interlayer between Co-W-S and Si was inserted to further optimize the PEC performance, especially the stability of the photocathode. As a result, an onset potential of 0.36 V vs. RHE, a photocurrent of 30.4 mA/cm2 at 0 V vs. RHE and an energy conversion efficiency of 4.0% were obtained under simulated AM1.5 G illumination, along with a long-term stability for 6 days of continuous PEC reaction.Graphical abstractGraphical abstract for this article
       
  • Acrolein production from methanol and ethanol mixtures over La- and
           Ce-doped FeMo catalysts
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Anita Borowiec, Aleksandra Lilić, Jean-Charles Morin, Jean-François Devaux, Jean-Luc Dubois, Simona Bennici, Aline Auroux, Mickaël Capron, Franck Dumeignil The acrolein production from methanol and ethanol mixtures over iron-molybdate-based catalysts was studied. The reaction to acrolein can be described by two successive steps: the first consists on the oxidation of both alcohols into their corresponding aldehydes and the second step is the subsequent aldol condensation of the as-formed aldehydes. The iron-molybdate catalysts were modified by doping with La and Ce (1%mol) in order to improve the aldol condensation step of the process. Series of catalysts were thus synthesized with different Mo/Fe ratios (i.e., 1.5, 2.0 and 2.5) and calcined at three different temperatures (i.e, 350 °C, 400 °C and 450 °C). The best catalytic performance was observed for FeMoCe2.0 (400 °C) for which the acrolein yield reached 42% (T = 320 °C, MetOH/EtOH = 1, GHSV = 3900 h−1). Furthermore, all the samples were characterised by TGA-DSC, HT-XRD, XPS, BET, LEIS, XRF, CO2-TPD, Pyridine (FTIR) and NH3 (calorimetry) adsorption. The increase in acrolein yield observed upon La and Ce doping was attributed to acid/base properties modification.Graphical abstractGraphical abstract for this article
       
  • Graphitic carbon nitride-carbon nanofiber as oxygen catalyst in
           anion-exchange membrane water electrolyzer and rechargeable metal–air
           cells
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Ji Eun Park, Mi-Ju Kim, Myung Su Lim, Sun Young Kang, Jong Kwan Kim, Seung-Hyeon Oh, Min Her, Yong-Hun Cho, Yung-Eun Sung Graphitic carbon nitride-carbon nanofiber (g-CN-CNF) was synthesized as a bifunctional catalyst in an anion-exchange membrane water electrolyzer (AEMWE), and primary and rechargeable Zn–air cells. The g-CN-CNF catalyst shows high catalytic activity for oxygen reduction reaction and oxygen evolution reaction in half-cell, with low overpotentials and low Tafel slopes. The high activity is attributed to the synergistic effect of abundant active sites and the electrical conductivity following the pyrolysis of g-CN and CNF. As a result, AEMWE with the g-CN-CNF anode, the first application of a carbon-based catalyst, exhibits outstanding performance that is the highest record in the literature for AEMWE using a non-noble metal catalyst. In addition, the performance and durability of Zn-air cells with g-CN-CNF cathode outperform those fabricated with commercial platinum.Graphical abstractGraphical abstract for this article
       
  • Effective shell wall thickness of vertically aligned ZnO-ZnS core-shell
           nanorod arrays on visible photocatalytic and photo sensing properties
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Kugalur Shanmugam Ranjith, Rutely Burgos Castillo, Mika Sillanpaa, Ramasamy Thangavelu Rajendra Kumar Development of hierarchical core-shell semiconductor heterostructures ensue significant advancement in catalytic functional structures with improvised optical functionalities. Shell wall controlled vertically aligned ZnO-ZnS core-shell nanorod (NR) heterostructures were grown on transparent conductive substrates along the c-axis by sulfidation of aligned ZnO nanorod arrays for visible photocatalytic properties. The effects of the sulfidation time on the morphology, crystalline properties, optical property, photocurrent response, and photocatalytic activity of the catalyst arrays were studied under UV and visible light irradiation. The shell wall thickness of these heterostructures influenced in great extent the effective photo responsive charge separation and improved carrier mobility. ZnO-ZnS core-shell heterostructure having the shell wall thickness of 20 nm has exhibited more efficient visible photocatalytic behavior due to effective separation of carriers and improved visible absorption. On further increasing the wall thickness the catalytic efficiency was reduced due to the poor carrier (hole) mobility in the polycrystalline shell grains which induced the higher recombination rate. Stability and reusability of ZnO-ZnS core-shell nanostructures reveals that the ZnS acted as a protective layer over the ZnO NR arrays. In appraisal with ZnO NR arrays, the control over the shell wall thickness of ZnO-ZnS core-shell NR array attributed to the excellent visible photocatalytic activity and improvised absorption of light in visible region at ZnO-ZnS interface and effective separation of photogenerated electron-hole pairs at ZnO-ZnS heterojunctions.Graphical abstractGraphical abstract for this article
       
  • The influence of phosphorus on the catalytic properties, durability,
           sulfur resistance and kinetics of Cu-SSZ-13 for NOx reduction by NH3-SCR
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Zhen Chen, Chi Fan, Lei Pang, Shujun Ming, Peng Liu, Tao Li The influence of phosphorus on the catalytic properties, durability, sulfur resistance and kinetics of Cu-SSZ-13 for NOx reduction by ammonia selective catalytic reduction (NH3-SCR) were systematically investigated to obtain a deeper understanding of the deactivation of Cu-SSZ-13 in the presence of phosphorus-containing impurities in diesel exhaust. An enhanced effect on NO conversion at low phosphorus loading was found above 450 ℃, probably due to the reduction of copper oxides that promote NH3 oxidation at high temperatures. As the phosphorus loading reached 0.4 mmol/gcatal, the framework dealumination and decrease of the BET specific surface area, acidity, and isolated Cu2+ ions accounted for the decrease in activity and hydrothermal stability over the entire temperature range. Simultaneously, the activity of phosphorus-impregnated samples tested in the presence of SO2 indicates that phosphorus accelerates the deactivation of Cu-SSZ-13 in the presence of SO2 at low temperatures, primarily due to the severe decrease of the Cu2+ ion content and partial coverage of the acid sites and active sites by phosphate and sulfate species. Additionally, kinetic analysis further demonstrated that phosphorus has an inhibitory effect on the SCR reaction rates at low temperatures and high phosphorus addition changes the NH3-SCR reaction kinetic parameters. The data presented herein provide a comprehensive picture of the interaction between phosphorus and Cu-SSZ-13.Graphical abstractGraphical abstract for this article
       
  • Regeneration of a sulfur-poisoned methane combustion catalyst: Structural
           evidence of Pd4S formation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Ville H. Nissinen, Niko M. Kinnunen, Mika Suvanto Decomposition of PdSO4, a species responsible for the deactivation of Pd-based methane combustion catalysts, was studied using a PdSO4/Al2O3 model system. PdSO4 was observed to behave differently under different reaction conditions. The decomposition of PdSO4 under inert atmosphere probably involved only one reaction step and resulted in the formation of metallic palladium. Under H2-containing atmosphere, the decomposition of PdSO4 resulted eventually in the formation of Pd4S, which is probably one of the many possible sulfur-containing palladium species that can be formed during regeneration of a sulfur-poisoned Pd-rich methane combustion catalyst. The formation of Pd4S can provide a reasonable explanation to the threshold temperature of sulfur removal from the catalyst, as well as to the residual sulfur present in the catalyst after regeneration under reductive atmosphere. Overall, the results obtained in the study provide deeper insight into the regeneration process of Pd-based catalysts, possibly enabling development of a more efficient regeneration strategy.Graphical abstractGraphical abstract for this article
       
  • Effects of dealumination on the performance of Ni-containing BEA catalysts
           in bioethanol steam reforming
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Wojciech Gac, Magdalena Greluk, Grzegorz Słowik, Yannick Millot, Laetitia Valentin, Stanislaw Dzwigaj The effects of dealumination of BEA zeolite on the formation of nickel active sites and the performance of Ni-containing BEA zeolite catalysts in the steam reforming of ethanol have been studied. Ni-containing BEA zeolite catalysts were prepared by the impregnation of unmodified and dealuminated BEA zeolites with Ni(NO3)2 precursor. The properties of Ni10HAlBEA and Ni10SiBEA zeolite catalysts were studied by means of X-ray diffraction, 1H, 27Al and 29Si magic-angle spinning nuclear magnetic resonance, Fourier-transform infrared and Raman spectroscopy, transmission electron microscopy, temperature-programmed reduction, temperature-programmed ammonia and hydrogen desorption methods. High initial activity and selectivity of Ni10HAlBEA to hydrogen and carbon dioxide with unmodified BEA zeolite support in the steam reforming of ethanol reaction performed at 500 °C was observed. However, fast deactivation of Ni10HAlBEA catalyst, manifested in the decrease of water conversion, drop of selectivity to H2 and CO2, and increase in the selectivity to ethylene with the time-on-stream, was observed. In contrast, Ni10SiBEA zeolite catalyst showed lower initial activity but higher durability and resistance for carbon deposition. It was stated that dealumination of BEA zeolite led to the slight structural changes and simultaneously pronounced decrease of acidity. Formation of the large nickel crystallites was hindered on Ni10SiBEA zeolite catalyst. TEM and Raman spectroscopy studies indicated that deactivation of Ni10HAlBEA was related to formation of nickel mediated filamentous, graphitic and amorphous carbon deposits. Much smaller amounts of filamentous carbons were observed on the Ni10SiBEA zeolite catalyst prepared by the use of dealuminated zeolite support.Graphical abstractGraphical abstract for this article
       
  • An active and robust Si-Fe/N/C catalyst derived from waste reed for oxygen
           reduction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Qiliang Wei, Xiaohua Yang, Gaixia Zhang, Dongniu Wang, Lucia Zuin, Dustin Banham, Lijun Yang, Siyu Ye, Youling Wang, Mohamed Mohamedi, Shuhui Sun The conversion of biomass waste into valuable carbon composites as efficient non-precious metal oxygen-reduction electrocatalysts is attractive for the development of commercially viable fuel-cell and metal-air battery technologies. Herein, a highly active and robust Si-contained Fe/N/C catalyst is prepared based on the porous carbon deriving from waste reed stalk after carbonization and KOH corrosion. Reed waste is a natural, abundantly available, and yearly renewable source, acting as the single precursor for Si containing-carbon substrate. The typical product (Si-Fe20/N/C1_6 in this work) possesses a high BET specific surface area, porous structure with high pyridinic-N and pyrrolic-N content. The X-ray absorption near edge structure (XANES), Raman, X-ray photoelectron spectroscopy (XPS) measurements and electrochemical measurements show that Si facilitates incorporation of more N to coordinate with Fe in the porous carbon and induces more graphitic carbon in the catalyst. The sample Si-Fe20/N/C1_6 exhibits better activity and superior stability than the Fe20/N/C counterpart and commercial Pt/C catalyst for the oxygen reduction reaction (ORR) in 0.1 M KOH electrolyte. The results suggest a promising route based on economical and sustainable biomass towards the development and engineering of value-added carbon materials as robust catalysts for oxygen reduction.Graphical abstractGraphical abstract for this article
       
  • Facet effect of Co3O4 nanocrystals on visible-light
           driven water oxidation
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Xichen Zhou, Zhen Liu, Yifan Wang, Yong Ding The deep comprehension of water oxidation mechanisms and structure-activity relationships on heterogeneous catalysts remains challenging. Here, facet effect of model spinel Co3O4 on water oxidation driven by visible-light is investigated in a well-established [Ru(bpy)3]2+-S2O82− (bpy = 2,2-bipyridine) biomimetic system to unveil the internal water oxidation mechanism for the first time. Spinel Co3O4 catalysts in the morphologies of nanocube, nanorod and nanosheet are synthesized successfully by bottom-up nanotechnologies, and they predominantly expose the well-defined crystal planes of {100}, {110} and {112}, respectively. Using time-resolved laser flash photolysis approach, the dynamically electronic transfer in photocatalytic courses of three Co3O4 catalysts are distinguished in the nanosecond scale. The three model catalysts show a facet-dependent activity rule that the water oxidation performance of {112} is similar with that of {110} and much better than that of {100}. The Co2+-Co2+ active sites with an ionic distance of 3.495 Å for catalyzing water oxidation only appear in {112} and {110} planes except for {100}, which is possibly responsible for the unique activity order of three Co3O4 catalysts. Furthermore, the Co2+ ions in the tetrahedral sites of spinel Co3O4 are confirmed to be more active than the Co3+ ions in the octahedral sites under visible-light driven water oxidation. The new insights shed a light on developing advanced nanocatalysts for oxygen evolution reaction.Graphical abstractThrough the facet effect of spinel Co3O4 with predominantly exposed crystal planes of {100}, {110} and {112}, a superior Co2+-Co2+ active sites with an ionic distance of 3.495 Å is discovered for photocatalytic water oxidation.Graphical abstract for this article
       
  • A rapidly room-temperature-synthesized Cd/ZnS:Cu nanocrystal photocatalyst
           for highly efficient solar-light-powered CO2 reduction
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Xianguang Meng, Guifu Zuo, Peixiao Zong, Hong Pang, Jian Ren, Xiongfeng Zeng, Shanshan Liu, Yi Shen, Wei Zhou, Jinhua Ye An ideal photocatalyst that can promisingly convert CO2 should have suitable band gap and fully consider the activation of reaction. However, well-designed photocatalytic materials with these aspects are very limited. This study reports a highly efficient CO2 reduction photocatalyst based on ZnS nanocrystals which can be rapidly synthesized at room temperature and operated under solar light irradiation at all-inorganic reaction system. Two functional elements, Cu and Cd, are respectively used as dopant and cocatalyst of ZnS nanocrystal for selective CO2 reduction. Cu+ doping expands the photoabsorption of ZnS into visible light region and the simultaneous Cd2+ surface modification significantly improves the activity of CO2 reduction with 99% formic acid selectivity. A combination of charge density distribution and electronic state studies reveal that the Cd s orbital displays obviously higher density of states near band-edge with a relatively lower lying band center than that of Zn s orbital. This will greatly favor the charge transfer from conduction band of ZnS to the surface state created by Cd2+ for catalyzing CO2 reduction.Graphical abstractAn efficient and solar light active CO2 reduction photocatalyst is designed by rationally engineering ZnS nanocrystals through Cu+ doping and Cd2+ surface modification. The Cd/ZnS:Cu is noble metal free and can be instantly synthesized at room temperature. It is an ideal model catalyst and has wide applications related to photocatalytic CO2 reduction.Graphical abstract for this article
       
  • A high-performance Bi2O3/Bi2SiO5 p-n heterojunction photocatalyst induced
           by phase transition of Bi2O3
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Haojie Lu, Qiang Hao, Tong Chen, Linghua Zhang, Daimei Chen, Chao Ma, Wenqing Yao, Yongfa Zhu In this work, Bi2O3/Bi2SiO5 p-n heterojunction photocatalyst was successfully fabricated via a facile one-step synthesis using Bi(NO3)3 and nano-SiO2 as precursors. With the increasing amount of SiO2, α-Bi2O3 gradually transferred into β-Bi2O3, and Bi2O3/Bi2SiO5 p-n heterojunction was obtained at the same time. The as-prepared samples were systematically characterized by XRD, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS). The Bi2O3/Bi2SiO5 heterojunction photocatalysts exhibited higher photocatalytic activity than α-Bi2O3 on the degradation of organic pollutants under simulated sunlight irradiation. The enhanced photocatalytic activity could be ascribed to the larger specific surface area, the larger contact angle, the formation of β-Bi2O3 and construction of p-n heterojunction. More importantly, the phase transition mechanism of Bi2O3 in Bi2O3/Bi2SiO5 heterojunction photocatalyst was proposed, which is significant for the theoretical study and application of photocatalytic materials.Graphical abstractGraphical abstract for this article
       
  • Exceptional visible-light activities of g-C3N4 nanosheets dependent on the
           unexpected synergistic effects of prolonging charge lifetime and
           catalyzing H2 evolution with H2O
    • Abstract: Publication date: 5 December 2018Source: Applied Catalysis B: Environmental, Volume 237Author(s): Xuliang Zhang, Xinxin Zhang, Jiadong Li, Jianhui Sun, Ji Bian, Jinshuang Wang, Yang Qu, Rui Yan, Chuanli Qin, Liqiang Jing It is highly desired to develop an efficient g-C3N4-based photocatalyst for energy production under visible-light irradiation. Herein, it is shown that the optimized g-C3N4 nanosheet-based photocatalyst could exhibit exceptional photocatalytic activities for H2 evolution under visible-light irradiation, by ∼14-time improvement compared to that of bare g-C3N4 one. It is confirmed by the methods of transient-state surface photovoltage responses, transient-state PL spectra and electrochemical measurements that the exceptional photocatalytic activities are attributed to the unexpected synergistic effects of prolonging the charge lifetime and catalyzing H2 evolution by coupling nanocrystalline anatase TiO2 as a proper-energy platform to accept visible-light-excited electrons from g-C3N4 and by decorating a nano-sized noble metal as the co-catalyst respectively. Among three decorated noble metals (Ag, Au and Pt), to prolong the photogenerated charge lifetime is much meaningful for the used noble metal cocatalyst with weak catalytic function like Ag in H2 evolution. Using nanocrystalline SnO2 to replace TiO2 is also applicable for the synergistic effect. Moreover, it is clarified by the designed experiment on photocatalytic CO2 conversion to CD4 in the presence of methanol in D2O that the resource of evolved H2 is mainly from the adsorbed H2O other than the disassociated H+ from methanol.Graphical abstractSynergistic effect between prolonging charge lifetime and improving catalyzing capability leads to improved H2-evolution photoactivity.Graphical abstract for this article
       
 
 
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