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  Subjects -> ENGINEERING (Total: 2567 journals)
    - CHEMICAL ENGINEERING (217 journals)
    - CIVIL ENGINEERING (227 journals)
    - ELECTRICAL ENGINEERING (129 journals)
    - ENGINEERING (1340 journals)
    - ENGINEERING MECHANICS AND MATERIALS (404 journals)
    - HYDRAULIC ENGINEERING (58 journals)
    - INDUSTRIAL ENGINEERING (87 journals)
    - MECHANICAL ENGINEERING (105 journals)

ENGINEERING (1340 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: 9)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 8)
ACS Nano     Hybrid Journal   (Followers: 328)
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: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 5)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 9)
Advanced Journal of Graduate Research     Open Access  
Advanced Nonlinear Studies     Hybrid Journal  
Advanced Science     Open Access   (Followers: 8)
Advanced Science Focus     Free   (Followers: 5)
Advanced Science Letters     Full-text available via subscription   (Followers: 11)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 8)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 16)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 6)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 9)
Advances in Engineering Software     Hybrid Journal   (Followers: 29)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 17)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 24)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
Advances in Nonlinear Analysis     Open Access  
Advances in Operations Research     Open Access   (Followers: 12)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 16)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 52)
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: 36)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 2)
Al-Nahrain Journal for Engineering Sciences     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 2)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 10)
American Journal of Engineering Education     Open Access   (Followers: 12)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 25)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Annals of Civil and Environmental Engineering     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of Regional Science     Hybrid Journal   (Followers: 8)
Annals of Science     Hybrid Journal   (Followers: 8)
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: 7)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 20)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 14)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 9)
Applied Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 6)
Applied Sciences     Open Access   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 7)
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: 6)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 9)
Arid Zone Journal of Engineering, Technology and Environment     Open Access   (Followers: 2)
Arkiv för Matematik     Hybrid Journal   (Followers: 2)
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: 2)
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 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  
AURUM : Mühendislik Sistemleri ve Mimarlık Dergisi = Aurum Journal of Engineering Systems and Architecture     Open Access  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autocracy : Jurnal Otomasi, Kendali, dan Aplikasi Industri     Open Access  
Automotive Experiences     Open Access  
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Avances en Ciencias e Ingenierías     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 2)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 6)
Bautechnik     Hybrid Journal   (Followers: 2)
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: 2)
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: 13)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering     Hybrid Journal   (Followers: 2)
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: 19)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 36)
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: 5)
BioNanoMaterials     Open Access   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 40)
Bitlis Eren University Journal of Science and Technology     Open Access  
Black Sea Journal of Engineering and Science     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: 15)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers Droit, Sciences & Technologies     Open Access  
Calphad     Hybrid Journal   (Followers: 2)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 32)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 47)
Carbon Resources Conversion     Open Access   (Followers: 1)
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: 10)
Catalysis Science and Technology     Hybrid Journal   (Followers: 10)
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: 3)
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)
Ciencia y Tecnología     Open Access  
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: 23)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
Clinical Science     Hybrid Journal   (Followers: 8)
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: 3)
Cognitive Computation     Hybrid Journal   (Followers: 3)
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 Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
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: 29)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Composite Structures     Hybrid Journal   (Followers: 298)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 241)
Composites Part B : Engineering     Hybrid Journal   (Followers: 272)
Composites Science and Technology     Hybrid Journal   (Followers: 208)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 18)
Computational Optimization and Applications     Hybrid Journal   (Followers: 8)

        1 2 3 4 5 6 7 | Last

Similar Journals
Journal Cover
Applied Catalysis B: Environmental
Journal Prestige (SJR): 3.152
Citation Impact (citeScore): 11
Number of Followers: 20  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0926-3373
Published by Elsevier Homepage  [3161 journals]
  • The effect of Si/Al ratio of zeolite supported Pd for complete CH4
           oxidation in the presence of water vapor and SO2
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Ida Friberg, Nadezda Sadokhina, Louise Olsson The catalytic properties of palladium supported on H-beta and H-SSZ-13 zeolite with different silica to alumina ratio (SAR) have been evaluated for complete CH4 oxidation in the presence and absence of water vapor and together with SO2. Different SAR was successfully obtained by dealumination of the zeolites in an acidic solution at elevated temperature. Flow reactor experiments showed that the SAR of the zeolite support greatly impacts the catalytic activity, especially in the presence of water vapor. Pd supported on a highly siliceous beta zeolite expressed high and stable CH4 conversion in the presence of water vapor, whereas the activity for Pd supported on zeolites with low SAR or Al2O3 decreased over time due to accumulative water deactivation. Hence, an increased SAR of the zeolite support clearly correlates to a lower degree of water deactivation. We suggest that this is a result of the high hydrophobicity of the siliceous zeolites. The results also imply that the catalytic activity in the presence of water vapor is influenced more by the SAR than the type of the zeolite framework. The CH4 oxidation activity was also enhanced with increasing SAR under dry conditions. This was addressed to the formation of more Pd particles in relation to ion-exchanged Pd2+ species and changes of the oxidation-reduction behavior of the Pd. The high number of acidic sites in zeolites with low SAR provided higher dispersion of Pd particles and formation of more monoatomic Pd2+ species, whereas almost exclusively Pd particles of larger sizes were formed on the highly siliceous zeolites. The monoatomic Pd2+ species, mostly formed on zeolites with low SAR, were oxidized and reduced at significantly higher temperatures than Pd in the particle form. Hence, complete reduction or oxidation of the Pd supported on highly siliceous zeolites can be achieved at lower temperatures. Moreover, compared to Pd/Al2O3, the zeolite supported Pd expressed higher sensitivity to SO2. However, the major part of the catalytic activity could be regenerated more easily using siliceous zeolites as supports compared to Al2O3. We suggest that this is an effect of the lower SO2 adsorption on the zeolite supports than on the Al2O3 support, which results in the formation of more PdSOx species upon SO2 exposure. On the other hand, the low SO2 adsorption on the zeolites also results in less spillover of sulfur species from the support to the active PdO, which explains the facilitated regeneration.Graphical abstractHigh siliceous Pd zeolites enhances methane oxidation.* PdB40: Pd/BEA(SAR = 40); PdB511: Pd/BEA(SAR = 511); PdB969: Pd/BEA(SAR = 969); PdS43: Pd/SSZ-13(SAR = 43); PdS52: Pd/SSZ-13(SAR = 52); Pd/Al: Pd/Al2O3.Graphical abstract for this article
       
  • Atomically dispersed Mo atoms on amorphous g-C3N4 promotes visible-light
           absorption and charge carriers transfer
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Ruiyang Zhang, Penghui Li, Fang Wang, Liqun Ye, Abhijeet Gaur, Zeai Huang, Ziyan Zhao, Yang Bai, Ying Zhou Atomically dispersed atom catalysts with atomically distributed active metal centers have attracted great attention owing to the maximum atom efficiency and excellent selectivity. Herein, for the first time, we found atomically dispersed Mo atoms can be formed on g-C3N4, and induce its amorphous transformation. This amorphous transformation leads to the formation of strong band tails with remarkably enhancing the absorbance edge of Mo-C3N4 up to 750 nm, resulting in almost whole visible-light range absorption. The formation of new Mo-C and Mo-N bonds due to strong interfacial interaction between atomically dispersed Mo atoms and g-C3N4 provide new electron and hole transport pathways to accelerate the separation of charge carriers. As a result, amorphous Mo/C3N4 (a-Mo/C3N4) reveals excellent photoreduction of CO2, yielding CO and H2 productions of 18 and 37 μmol g−1 h−1 under visible-light illumination (λ > 420 nm), which manifest a remarkable 10.6- and 4-folds enhancement of that over crystalline g-C3N4. This finding provides a conceptually different approach to fabricate high-efficient photocatalyst through the strong interfacial interaction between atomically dispersed metal atoms and host.Graphical abstractGraphical abstract for this article
       
  • Ultra-small colloidal heavy-metal-free nanoplatelets for efficient
           hydrogen generation
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Haiguang Zhao, Hui Zhang, Guiju Liu, Xin Tong, Jiabin Liu, Gurpreet S. Selopal, Yiqian Wang, Zhiming M. Wang, Shuhui Sun, Federico Rosei Metal chalcogenide semiconducting nanoplatelets exhibit a broad absorption spectrum, as well as thickness-dependent optical and electronic properties. As such, they may be used as building blocks in a variety of optoelectronic devices. The direct synthesis of heavy-metal-free ultra-small sized nanoplatelets is still challenging, due to the inherent limits in existing synthetic approaches. Here, we report an efficient template-assisted cation-exchange route to synthesize heavy metal free metal chalcogenide nanoplatelets that are optically active in the near infrared. The SnSe nanoplatelets, whose lateral dimension is 6–10 nm, exhibit a quantum yield of 20%. The nanoplatelets are applied as light absorbers in a photoelectrochemical (PEC) system for hydrogen generation, leading to a saturated photocurrent density of 7.4 mA/cm2, which is a record for PEC devices using heavy metal-free colloidal quantum dots or nanoplatelets under identical measurement conditions. Our results indicate that quasi-zero-dimensional SnSe nanoplatelets hold great potential as efficient light absorbers for emerging optoelectronic technologies.Graphical abstractGraphical abstract for this article
       
  • 2D Co-incorporated hydroxyapatite nanoarchitecture as a potential
           efficient oxygen evolution cocatalyst for boosting photoelectrochemical
           water splitting on Fe2O3 photoanode
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Ruifeng Chong, Yuqing Du, Zhixian Chang, Yushuai Jia, Yan qiao, Shanhu Liu, Yong Liu, Yanmei Zhou, Deliang Li The serious charge recombination together with the sluggish water oxidation kinetics have largely limited the practical application of hematite (Fe2O3) in photoelectrochemical (PEC) water splitting. Surface modification with oxygen evolution cocatalyst is an efficient strategy to address the both issues. Herein, a novel 2D oxygen evolution cocatalyst, namely Co-incorporated hydroxyapatite (Co-HAP) nanoarchitecture, was rationally designed and decorated on Fe2O3 photoanode. The resulting Co-HAP decorated Fe2O3 (Co-HAP/Fe2O3) exhibited excellent PEC water splitting with a high photocurrent density of 2.25 mA cm−2 at 1.23 V vs. RHE in neutral electrolyte, which is ca. 9.78 times that for bare Fe2O3. Moreover, the onset potential displayed a 200 mV cathodic shift, indicating an accelerated water oxidation kinetics over Fe2O3. PEC characterizations revealed Co-HAP could not only significantly improve the charge-separation efficiency but also could enhance the surface charge-separation efficiency in the bulk and on the surface of Fe2O3. Comprehensive investigations unveiled the interfacial negative electrostatic field and the increased electrical conductivity arising from Co-HAP decoration were of great benefit to improve the charge separation and inhibit surface charge recombination, while the 2D architecture of Co-HAP offered high surface area and abundant exposed Co active sites, ultimately boosted PEC water splitting over Fe2O3. Owing to the superior ion-exchange ability of HAP, the strategy presented here would open a new vane to explore highly efficient oxygen evolution cocatalyst.Graphical abstract2D Co-incorporated hydroxyapatite exhibits excellent performance for boosting photoelectrochemical water splitting over Fe2O3 photoanode.Graphical abstract for this article
       
  • Two-dimensional dual carbon-coupled defective nickel quantum dots towards
           highly efficient overall water splitting
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Ziliang Chen, Hongbin Xu, Yuan Ha, Xuanyi Li, Miao Liu, Renbing Wu Rational design of highly efficient and cost-effective bifunctional electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is extremely desirable but still challenging for electrochemical water splitting. Herein, we report the synthesis of hybrid composites consisting of defective nickel quantum dots (Ni QD) encapsulated in N-doped carbon (NC) anchored on the surface of reduced graphene oxide (Ni QD@NC@rGO) through a low-temperature pyrolysis of rGO-wrapped two dimensional (2D) sheet-like nickel zeolite imidazolate framework. The as-fabricated Ni QD@NC@rGO catalysts only require overpotentials of 265 and 133 mV to deliver a current density of 10 mA cm–2 for OER and HER in 1.0 M KOH, respectively. Remarkably, an alkaline electrolyzer constructed with Ni QD@NC@rGO catalyst for both anode and cathode can drive a current density of 10 mA cm–2 at a low cell voltage of 1.563 V, superior to that of the Pt@C IrO2@C couple (1.614 V). The enhanced electrocatalytic performance of Ni QD@NC@rGO can be mainly attributed to its 2D hierarchically porous structure and the synergistic effect of the highly dispersed Ni QD, in-situ coupled thin-layer NC and rGO, giving rise to a large surface active sites exposure, enhanced electron/ion transfer ability and optimal Gibbs free energy of adsorption.Graphical abstractA bifunctional catalyst consisting of defective nickel quantum dots encapsulated in N-doped carbon anchored on the surface of reduced graphene oxide has been fabricated by a low-temperature pyrolysis of two-dimensional graphene-coupled sheet-like nickel zeolite imidazolate framework, which exhibits superior overall water-splitting performance to that of the IrO2@C Pt@C couple.Graphical abstract for this article
       
  • A nanoscale p–n junction photoelectrode consisting of an NiOx layer on a
           TiO2/CdS nanorod core-shell structure for highly efficient solar water
           splitting
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Il-han Yoo, Shankara S. Kalanur, Hyungtak Seo The TiO2/CdS system has attracted great attention in solar water-splitting applications owing to its desirable electronic and optical properties. With the aim of enhancing its photoelectrochemical water splitting efficiency, an efficient strategy is proposed via nanostructuring and linking it in a p–n junction configuration with NiOx. The deposition of TiO2 nanorods (NRs) and CdS was achieved using a hydrothermal synthesis route in the sequence, after which NiOx was deposited via RF magnetron sputtering. Characterisation revealed the uniform deposition of CdS onto the TiO2 NRs, forming a core-shell morphology, and the deposition of NiOx on top of the TiO2-NR/CdS resulted in a nanostructured p–n junction. X-ray photoelectron spectroscopy was used to resolve the valence band edge, and impedance studies confirmed the formation of a p–n junction; accordingly, the probable band edge positions of the photoelectrode were identified. The optimised TiO2-NR/CdS-NiOx p–n junction electrode exhibited a remarkable photocurrent of ˜30 mA cm−2 (at 1 V vs. Ag/AgCl) under AM 1.5 G simulated sunlight and an incident photon-to-current efficiency of ˜97% at 500 nm. Furthermore, during illumination, the production of H2 gas occurred with a faradaic efficiency of 95%. The results of the study demonstrate the advantage of utilizing the TiO2-NR/CdS-NiOx system in a p-n junction configuration to greatly enhancethe charge generation, separation and suppression of the charge recombination, which boosts its photoelectrochemical water-splitting performance.Graphical abstractGraphical abstract for this article
       
  • Developing superior catalysts engineered by multichannel healing strategy
           for advanced oxidation
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Hong Xia, Zhen Zhang, Jia Liu, Xingming Ning, Shouting Zhang, Xiaoquan Lu Catalyst deactivation derived from slow conversion of Fe(III)/Fe(II) is the critical problem restricting catalytic efficiency of advanced oxidation. Herein, a novel multichannel healing strategy is proposed for fast healing structural damage by designing rationally smart platform (TiO2-CDs-FeOOH hollow sandwich hybrid). This ingenious system shows remarkable catalytic activity (0.77 min−1) and stability towards the removal of organic contaminants. Systematic studies confirm that the excellent catalytic activity is attributed to multiple electron transfer (MET) behavior at interface between photocatalytic substrate and FeOOH, leading to highly efficient interfacial charge separation and then fast recovery of Fe(II) on FeOOH surface during H2O2 activation process. Notably, multichannel healing procedure and MET kinetic information are unveiled by UV–vis/scanning electrochemical microscopy (SECM) through an in situ probe scanning technique. A higher ET rate constant keff (0.92 × 10-2 cm s-1) was revealed over TiO2-CDs-FeOOH, two times that of TiO2-FeOOH, further confirming that multi-channel electron transfer could achieve fast Fe(III)/Fe(II) conversion. This work offers a new insight to design highly efficient catalysts for the practical applications of sustainable environmental remediation and energy conversion.Graphical abstractGraphical abstract for this article
       
  • Promotional effect of Ga for Ni2P catalyst on
           hydrodesulfurization of 4,6-DMDBT
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Jung-Geun Jang, Yong-Kul Lee Ni2P catalysts supported on SiO2 and Ga-SiO2 were prepared by incipient wetness impregnation technique, and the effect of the electronic properties of Ni2P on hydrodesulfurization (HDS) performance was studied. X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), and in situ FT-IR with CO adsorption studies were used to examine structural and electronic properties of the supported Ni2P catalysts. The catalytic activity in hydrodesulfurization (HDS) was measured at 3.0 MPa and at three different temperatures of 613, 628, and 643 K in a three-phase fixed bed reactor using a model feed containing 500 ppm S as 4,6-DMDBT, 6000 ppm S as DMDS, 100 ppm N as quinoline, 1 wt% tetralin, and 0.5 wt% n-nonane in n-tridecane balance. In both cases, the HDS conversion was very high over 90%. For the product distributions, the Ni2P/SiO2 maintained a low direct desulfurization (DDS) selectivity at 26.5%, while the Ni2P/Ga-SiO2 exhibited higher DDS selectivity of 32.1% at 643 K. The Ni K-edge XANES and CO-adsorbed FT-IR analysis confirmed the electron enriched property of Ni2P on SiO2, but with the electron deficiency of Ni2P phase supported on Ga-SiO2 support. These results thus suggest that the electron deficient Ni2P favors σ-bonding with S compounds to promote direct desulfurization of 4.6-DMDBT.Graphical abstractGraphical abstract for this article
       
  • Engineering organic/inorganic hierarchical photocathode for efficient and
           stable quasi-solid-state photoelectrochemical fuel cells
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Yanhu Wang, Huihui Shi, Kang Cui, Jinghua Yu Photoelectrochemical fuel cells (PFCs) serve as a model system for harvesting electric energy from solar and biomass based on anodic fuel oxidation and cathodic oxygen reduction reaction (ORR). However, the sluggish ORR thereby limits the performance of PFC. Herein, we present a novel photocathode with polyterthiophene (pTTh) coated p-type cuprous oxide (Cu2O) (pTTh-Cu2O) that achieves boosted ORR kinetics, as well as exhibits remarkably improved photostability. By utilizing a hydrogel electrolyte which can avoid the leakage and volatilization of liquid electrolyte, a quasi-solid-state PFC device with eminent stability that consists of gold nanoparticles (Au NPs) decorated TiO2 nanorod arrays (Au-TiO2 NRAs) photoanode and pTTh-Cu2O photocathode can be assembled. And the fabricated PFC exhibits outstanding performance that yields an open circuit voltage of 0.78 V and a maximum power density of 130 μW·cm−2 utilizing glucose as feeding under illumination. Furthermore, the as-prepared quasi-solid-state PFC demonstrates its potential for practical application by lighting a commercial light-emitting diode (LED). It is our believe that such rational design not only can be expanded for organic wastes degradation and water splitting, but also shed a light on the development of portable electronics driven by solar.Graphical abstractGraphical abstract for this articleA quasi-solid-state tandem photoelectrochemical fuel cell that yields an open circuit voltage of 0.78 V and a maximum power density of 130 μW·cm−2 was assembled by utilizing hydrogel electrolyte, Au-TiO2 NRAs photoanode and pTTh-Cu2O pohotocathode. The pTTh-layer protected Cu2O exhibited remarkably improved photostability as well as achieved significantly accelerated oxygen reduction reaction performance.
       
  • Efficient photocatalytic H2 evolution using NiS/ZnIn2S4 heterostructures
           with enhanced charge separation and interfacial charge transfer
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Aihua Yan, Xiaowei Shi, Fei Huang, Mamoru Fujitsuka, Tetsuro Majima The effect of multidimensional heterostructures on charge transfer and charge separation is intriguing in photocatalytic applications. Herein, NiS/ZnIn2S4 heterostructures with tailorable composition, tunable light absorption, and controllable band gap were successfully prepared by a two-step method to show uniform NiS nanoparticles with an average size of 10 nm loaded homogeneously on porous ZnIn2S4 nanosheets. Consequently, NiS/ZnIn2S4 heterostructures have markedly enhanced light absorption and efficient photocatalytic efficiency, reaching the hydrogen evolution rate of 5.0 μmol  h−1 under the light irradiation at 420 nm, to be approximately three times higher than that of pure ZnIn2S4. The enhanced photocatalytic efficiency results from faster charge transfer and more efficient photogenerated electron-hole separation under beneficial band alignment. The results shed light on how the photocatalytic reaction occurs at the interface between NiS and ZnIn2S4, and can open a new avenue for synthesizing efficient photocatalysts.Graphical abstractGraphical abstract for this article
       
  • Construction of g-C3N4/PDI@MOF heterojunctions for the highly efficient
           visible light-driven degradation of pharmaceutical and phenolic
           micropollutants
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Yuanyuan Li, Yu Fang, Zhenlei Cao, Najun Li, Dongyun Chen, Qingfeng Xu, Jianmei Lu A novel g-C3N4/PDI@MOF heterojunction was synthesized by the in situ growth of NH2-MIL-53(Fe) onto the g-C3N4/PDI layer. The heterojunction was applied as a photocatalyst for the removal of pharmaceutical and phenolic micropollutants in the present of H2O2 and visible LED light (420 
       
  • MOF-derived 3D Fe-N-S co-doped carbon matrix/nanotube nanocomposites with
           advanced oxygen reduction activity and stability in both acidic and
           alkaline media
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Huihui Jin, Huang Zhou, Daping He, Zhihao Wang, Qilei Wu, Qirui Liang, Suli Liu, Shichun Mu MOF-derived carbon-based nanomaterials have attracted great attention due to the outstanding electrocatalytic performance, low-cost and super stability. To design an excellent catalyst, Fe, N and S codoped carbon matrix/carbon nanotube nanocomposites (Fe-N-S CNN) are prepared by pyrolysis of ZIF-8 impregnated with iron salt in this work. Benefiting from the synergistic effect of carbon matrix and nanotubes, abundant iron nitrides and thiophene-S active sites, the Fe-N-S CNN exhibits an excellent oxygen reduction reaction (ORR) performance with a half-wave potential of 0.91 V vs. RHE in alkaline conditions and 0.78 V vs. RHE in acidic conditions, while those of commercial Pt/C catalysts are 0.85 V vs. RHE and 0.795 V vs. RHE, respectively. Furthermore, Fe-N-S CNN as the cathode catalyst in a primary zinc-air battery shows a specific capacity of 700 mA h g−1.Graphical abstractGraphical abstract for this article
       
  • A robust core-shell silver soot oxidation catalyst driven by Co3O4: Effect
           of tandem oxygen delivery and Co3O4-CeO2 synergy
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Xin Wang, Baofang Jin, Ruixue Feng, Wei Liu, Duan Weng, Xiaodong Wu, Shuang Liu In this work, tandem oxygen delivery systems were built by coating cube-like Co3O4 with Ag/CeO2, which exhibited high soot oxidation activity that overwhelmed the Fe2O3-based catalysts. The results of TPR and activity tests indicated that a large amount of Co3O4 lattice oxygen could be transferred into Ox− with the assistance of Ag/CeO2. These active oxygen species accelerated the oxidation of soot and NO at low temperature. Furthermore, the Co3O4-CeO2 synergy facilitated Co3+ → Co2+ transformation during reactions, resulting in boosted NO conversion and thereby NO2-assisted soot combustion at mild and high temperatures. Given the Ag/Co3O4@CeO2-type catalysts were low-cost, hydrothermally stable and could be fabricated via co-precipitation methods easily, they were highly promising for application in both gasoline and diesel particulate filters.Graphical abstractGraphical abstract for this article
       
  • Shape engineering of palladium aerogels assembled by nanosheets to achieve
           a high performance electrocatalyst
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Mehdi Zareie Yazdan-Abad, Meissam Noroozifar, Abdollatif Shafaei Douk, Ali Reza Modarresi-Alam, Hamideh Saravani Three-dimensional noble metal aerogels are unique solid materials with ultralow densities, large open pores, and high surface areas. Despite several research works on noble metal aerogels assembled by nanochains, the investigation of noble metal aerogels assembled by nanosheets has not been reported to date. In this work, palladium aerogels assembled by nanosheets have been synthesized in four various carboxylic acid (RCOOH) solvents with different alkyl groups (R= H– (formic acid, FA), CH3– (acetic acid, AA), CH3CH2– (propionic acid, PA), and CH3CH2CH2– (butyric acid, BA)). It has been found that the R groups play a crucial role in the morphology of palladium aerogels so that the Pd aerogels synthesized in acetic acid and propionic acid solvents show better morphology than that of palladium aerogels synthesized in formic acid and butyric acid solvents. The electrocatalytic activity and durability of all aerogels are evaluated using cyclic voltammetry (CV) and chronoamperometry (CA) experiments toward ethanol oxidation. Based on CV and CA data, Pd aerogels synthesized in AA and PA show high catalytic activity and durability due to their unique structures.Graphical abstractGraphical abstract for this article
       
  • Preparation of visible-light-responsive photocatalyst by
           dehydronitrization of gallium oxide hydroxide for hydrogen evolution from
           water
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Yuma Kato, Muneaki Yamamoto, Akiyo Ozawa, Tetsuo Tanabe, Tomoko Yoshida We have performed dehydronitrization of GaOOH under NH3 flow to produce nitrogen doped Ga2O3 and examined their photocatalytic activities for H2 evolution from an aqueous methanol solution under visible light irradiation. GaOOH was synthesized by hydrothermal treatment and dehydronitrided at a temperature ranging from 773 K to 1273 K under NH3 flow. At first, GaOOH was dehydrided to Ga2O3 under 873 K and followed nitrization. With increasing dehydronitrization temperature, the products were getting closer to full nitride (GaN). Among all dehydronitrided samples, only one sample sintered at 1173 K showed photocatalytic activity under visible light irradiation and its crystalline structure had not changed before and after the reactions, while other samples did not show the activity and were oxidized to GaOOH. From thermodynamical aspect, if nitrogen dissolved into oxide or making oxynitride, its chemical potential must be lower than that of N in GaN. Therefore, there should be some gallium oxinitride phase like GaNyO3-x stable in water showing photocatalytic activity.Graphical abstractGraphical abstract for this article
       
  • Co-aromatization of methane with propane over Zn/HZSM-5: The methane
           reaction pathway and the effect of Zn distribution
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Peng He, Jack S. Jarvis, Shijun Meng, Qingyin Li, Guy M. Bernard, Lijia Liu, Xiaohui Mao, Zhao Jiang, Hongbo Zeng, Vladimir K. Michaelis, Hua Song The co-aromatization of methane with propane is investigated using Zn/HZSM-5 as the catalyst at 400 °C. The presence of methane has a pronounced effect on the product distribution in terms of improved formation of phenyl rings and substitution groups of aromatic species. Isotopic labeling and solid-state NMR spectroscopy studies reveal that the favored site for methane incorporation varies at different stages along the co-aromatization reaction, from the benzylic sites at the initial stage to the phenyl rings and then substitution groups as the reaction proceeds. SIMS spectroscopy of the involved reaction intermediates suggests the formation of C4 species over the Zn sites that are bonding to the oxygen atoms of the zeolite framework, which is supported by theoretical calculations. The interaction between Zn species and the zeolite framework is also confirmed by XAS and changes in coordination environments are identified through XANES and solid-state NMR spectroscopy. The redistribution of Zn during the reaction is observed on the surface of the zeolite support. Scanning transmission X-ray microscopy images show that Zn is rich in the inner pores compared with the external surface of the catalyst particles in the pristine catalysts. XANES and XPS spectra demonstrate that the Zn concentration increases on the external surface after the reaction, a conclusion that is further supported by the theoretical study. The Zn redistribution might be among the reasons for methane participation pathway alternation during the co-aromatization, since the Zn species located within the inner pores and on the external surface might prefer to catalyze the methane incorporation to the phenyl rings and substitution groups of the formed aromatics, respectively.Graphical abstractMethane participation pathway during its co-aromatization with propane heavily depends on the local chemical environment and distribution of the zinc active sites on the Zn/HZSM-5 surface.Graphical abstract for this article
       
  • Correlation between the H2 response and its oxidation over TiO2 and N
           doped TiO2 under UV irradiation induced by Fermi level
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Kun Wang, Ting Peng, Zhongming Wang, Hong Wang, Xun Chen, Wenxin Dai, Xianzhi Fu In the previous work, we have ever found that the photocatalytic oxidation of a reactant gas over TiO2 would be somewhat dependent on the electron transfer behavior between the adsorbed gas and TiO2 under UV irradiation. To further confirm the viewpoint, in this work, a TiO2 (in-situ) sample was prepared by an in-situ method, and was tested its gas-sensing performance to H2 and its photocatalytic performance of oxidizing H2 as compared to a TiO2 (commercial) sample. It was found that TiO2 (in-situ) would increase the conductivity with the introduction of H2 under UV irradiation, but TiO2 (commercial) would decrease the conductivity in the same case. Based on the surface structural and electrochemical characteristics of samples, it was proposed that the existence of surface defects over TiO2 (in-situ) would decrease the Fermi level (EF), resulting in the electron transfer from the adsorbed H2 to TiO2, while the adsorbed H2 accepted electrons from TiO2 (commercial) due to its higher EF. Moreover, the adsorbed H2 on TiO2 (in-situ) could be oxidized under UV irradiation but that on TiO2 (commercial) could be hardly. This indicated that the photocatalytic oxidation of H2 over TiO2 would be dependent on the electron transfer direction between the adsorbed H2 and TiO2, i.e., the electron-donated H2 could be oxidized, while the electron-accepted H2 could be not. This above effect induced by the surface defects could be further demonstrated by a N-doped TiO2 (N-TiO2) sample. This N-TiO2 owned a lower EF than TiO2 (in-situ) due to the introduction of a more impurity defects, resulting in a more electron transfer from the adsorbed H2 to N-TiO2 and then the oxidation of more H2. This study also indicated that the adjustment of EF could improve the photocatalytic activity of oxidizing H2 by changing the adsorbed behavior of H2 over TiO2, which may be applicable for investigating other reactants’ oxidation behaviors over other semiconductor photocatalysts.Graphical abstractThe absorbed H2 over TiO2 (commercial) accepted electrons from its surface due to the higher EF* of TiO2 (commercial) under UV irradiation, while the adsorbed H2 over TiO2 (in-situ) or N-TiO2 samples acted as an electron donor due to its lower EF*. Moreover, the electron-donated H2 could be oxidized by O2 but the electron-accepted H2 could not.Graphical abstract for this article
       
  • Facile assembled biochar-based nanocomposite with improved graphitization
           for efficient photocatalytic activity driven by visible light
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Shujing Ye, Min Yan, Xiaofei Tan, Jie Liang, Guangming Zeng, Haipeng Wu, Biao Song, Chengyun Zhou, Yang Yang, Han Wang The preparation processes of efficient photocatalyst containing defect regulation and heterostructure construction are usually complicated and difficult to control at present, besides, the catalyst agglomeration in solution further limits their application. There is an urgent need for designing a potentially cheap, efficient, sustainable and easy-prepared nanocomposite to improve photocatalytic performance. In present study, the facile synthesized porous graphitic carbon with microtubular structure, high graphitization degree and abundant porosity demonstrates an outstanding advantage of excellent conductivity and facilitated mass transport. Such porous graphite biochar (PGBC) self-assembled with g-MoS2 nanosheets is observed by the optimized band gap, enhanced visible light harvesting, accelerated charge transfer and efficient photo-generated carrier’s separation. Considering the favorable specific surface area and pore distribution of PGBC for avoiding nanosheet agglomeration, the as-prepared composites display quite high efficiency for tetracycline hydrochloride (TC) removal based on the synergistic action of the desirable absorption and photocatalytic capability. Mechanism exploration indicates that surface adsorption is mainly dominated by electrostatic interaction, hydrogen bonding, π-π stacking and pore-filling, and hole (h+) and hydroxyl radical (·OH) are the predominant active species responsible for TC degradation. Furthermore, the nanocomposites possess advisable stability performance for TC removal in contaminated river water, further providing an underlying insight for establishing high-efficient and easy-prepared photocatalysts in practical contaminated water remediation.Graphical abstractGraphical abstract for this article
       
  • Bifunctional porous Co-doped NiO nanoflowers electrocatalysts for
           rechargeable zinc-air batteries
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Jinmei Qian, Xiaosong Guo, Tongtong Wang, Peitao Liu, Hong Zhang, Daqiang Gao Zinc-air batteries (ZnABs) represent one of the most promising options to power next-generation electric vehicles owing to their high theoretical energy density and reliable safety. However, their further development and application is hampered due to the lack of high-efficiency bifunctional air electrocatalysts. Herein, porous Co-doped NiO nanoflowers (Co-NiO NFs) with outstanding electrocatalytic activity and stability toward oxygen evolution reaction (ORR) and oxygen reduction reaction (OER) is reported for the first time, including a positive half-wave potential (0.79 V) for ORR and a small overpotential (1.53 V at 10 mA cm−2) for OER. Firstly, the synergistic effect between the sound two-dimensional (2D) hexagonal framework and numerous nanopores inside the nanosheets offers an available surface for O2 adsorption/diffusion, and a large effective electrochemical active surface area for exploring and utilizing more active sites. Secondly, Co dopants can effectively increase the conductivity of pristine NiO nanoflowers (NFs) and simultaneously enhances the intrinsic ORR and OER activity. Notably, the liquid ZnABs with engineered Co-NiO NFs electrode exhibits a high discharge peak power density of 93 mW cm−2, a satisfactory specific capacity of 830 mA h g-1 at the current density of 5 mA cm−2, together with excellent cycling stability of 110 h at 2 mA cm−2. Additionally, the corresponding all-solid-state ZnABs assembled with Co-NiO NFs shows a long durability with the stable charge-discharge cycles of 6 h and good flexible nature.Graphical abstractGraphical abstract for this article
       
  • Effective hydrogenation of g-C3N4 for enhanced photocatalytic performance
           revealed by molecular structure dynamics
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Yan Gong, Hongkun Li, Chen Jiao, Qingchi Xu, Xiangyu Xu, Xiuming Zhang, Yufei Liu, Ziyang Dai, Xiang Yang Liu, Wei Chen, Lei Liu, Da Zhan In this work, we report a simple, facile and effective method to simultaneously hydrogenate and exfoliate graphitic-C3N4 (g-C3N4) through high concentration sulfuric acid treatment. The hydrogenation mechanism of g-C3N4 is explained experimentally and it is further revealed in detail by molecular structure dynamics as well as the corresponding electronic structure evolutions. Five different atomic sites in unit cell of g-C3N4 are structurally available to be hydrogenated, and four of them are energetically favored to form hydrogenated structures. Different from the pristine g-C3N4 that is flat in basal plane, the energetically favored hydrogenation structure of g-C3N4 possesses the corrugated fluctuation plane. The hydrogenated g-C3N4 structures also present blueshifted UV–vis absorption and photoluminesce (PL) peaks compared to that of pristine g-C3N4, and it is well explained by theoretical calculation results that the bandgap becomes larger due to hydrogenation. Finally, it is found that the photocatalytic performance of g-C3N4 is dramatically enhanced once the crystal structure is hydrogenated. The enhanced photocatalytic performance is mainly attributed to the hydrogenation caused spatial charge separation due to the redistribution of charge density in both valence band maximum and conduction band minimum. The revealing of spatial charge separation provides insight into the deep understanding of hydrogenation mechanism of g-C3N4, which is critically significant for designing light-efficient photocatalysis.Graphical abstractGraphical abstract for this article
       
  • Synergistic effect of artificial enzyme and 2D nano-structured Bi2WO6 for
           eco-friendly and efficient biomimetic photocatalysis
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Huan Yi, Ming Yan, Danlian Huang, Guangming Zeng, Cui Lai, Minfang Li, Xiuqin Huo, Lei Qin, Shiyu Liu, Xigui Liu, Bisheng Li, Han Wang, Maocai Shen, Yukui Fu, Xueying Guo Highly-efficient and eco-friendly materials and technologies are urgently needed to meet the requirements of nowadays green development. Photocatalysis with using solar energy and enzymatic catalysis with eco-friendly nature are effective alternatives to address the problem. Notably, beneficial use of the synergistic effect of artificial enzyme and advanced photocatalyst has attracted wide attention. This work presents a biomimetic photocatalytic material, two-dimensional (2D) biomimetic hemin-bismuth tungstate (HBWO). Stable HBWO composites formed by immobilization of monomeric hemin on 2D bismuth tungstate layer, exhibit high photocatalytic performance, better than that of pure 2D bismuth tungstate and unsupported hemin. HBWO shows layered structure with the interlayer spacing at ˜0.35 nm. In the photocatalytic process, hemin can not only act as an electron shuttle, also play an important role in oxygen transfer. Additionally, the synthesized HBWO composites exhibit nice binding affinities and high photocatalytic activity in tetracycline degradation. It is anticipated that beneficial use of synergistic effect of artificial enzyme and photocatalyst via HBWO composites can be a promising eco-friendly and efficient solution for addressing the environmental crisis.Graphical abstractGraphical abstract for this article
       
  • Engineering of reduced graphene oxide on nanosheet–g-C3N4/perylene imide
           heterojunction for enhanced photocatalytic redox performance
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Liping Yang, Pengyuan Wang, Jiao Yin, Chuanyi Wang, Guohui Dong, Yuanhao Wang, Wingkei Ho g-C3N4-based photocatalysts are recognized as promising candidates for photocatalytic purification of air and solar energy conversions; but their practical application is still limited by the sluggish charge transfer dynamic. Herein, a Z-scheme ternary heterojunction (nanosheet–g-C3N4 [NCN]/perylene imide [PI]/reduced graphene oxide [rGO], NCN/PI/rGO) was successfully constructed. For experimental comparison, NCN/rGO/PI was concurrently synthesized through different reaction sequences. In these ternary heterojunction systems, the introduction order of rGO affects the morphology structure and the interaction between phases and results in two diverse electron transfer modes which determine the different photocatalytic redox performances. The as-obtained NCN/PI/rGO Z-scheme heterostructure exhibited superior photocatalytic activity towards the photocatalytic removal of NO and generation of H2O2 under visible light irradiation. Such photocatalytic activity was about 1.58 and 1.23 times higher than those of NCN and NCN/PI, respectively, in NO removal. Such enhanced photocatalytic properties can be ascribed to the two-step electron transfer process involving the CB electrons in PI combined with the VB holes of NCN via the Z-scheme pathway (process I, PI→NCN) because PI was grown in situ on the NCN through thermal condensation polymerisation. This process enabled intimate contact between NCN and PI and a short charge-transfer distance. The residual electrons in the CB of NCN then flowed into the rGO (process II, PI→NCN→rGO). Thus, the simultaneous occurrence of two electron transfers processes I and II help improve the photocatalytic activity. Constructing NCN/PI/rGO Z-scheme heterostructures is anticipated to be an effective strategy for developing high-performance photocatalysts that facilitate the utilisation of solar energy.Graphical abstractGraphical abstract for this article
       
  • Highly efficient Z-scheme structured visible-light photocatalyst
           constructed by selective doping of Ag@AgBr and Co3O4 separately on {010}
           and {110} facets of BiVO4: Pre-separation channel and hole-sink effects
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Fangfei Chen, Chaoyue Wu, Jinnan Wang, Corvini Philippe François-Xavier, Thomas Wintgens To improve the visible-light photocatalytic activity and photo-carriers separation of BiVO4, highly efficient Z-scheme structured visible-light photocatalyst Ag@AgBr/BiVO4/Co3O4 was constructed by selective doping of Ag@AgBr and Co3O4 on {010} and {110} facets of BiVO4. Due to the different energy levels of conduction band (CB) and valence band (VB) between {010} facet and {110} facet, BiVO4 could act as the ‘pre-separation channel’ to achieve spatial charge separation. Such pre-separation channel effect improved photo-electrons transfer from BiVO4{010} facets to electron mediator (Ag°) for subsequent recombination with holes of AgBr. Thus, the photo-induced electrons of AgBr could be accumulated on CB for reduction of O2 to O2−. On the other hand, holes of BiVO4 accumulated on {110} facets were captured by deriving-hole-type co-catalysts Co3O4 for organics oxidation. In addition, Ag° not only served as the electron mediator of Z-scheme but also improve the visible-light utilization due to SPR-effect. Being attributed to the synergistic effect of pre-separation channel and deriving-hole-type co-catalysts, Z-scheme structured Ag@AgBr/BiVO4/Co3O4(0.15 wt%) achieved high photodegradation rate of organics. Even after 9th cycles, Ag@AgBr/BiVO4/Co3O4(0.15 wt%) could still photodegraded more than 90% of OTC within 24 min. DRS, PL and photoelectrochemical analyses also confirmed the improvement of visible-light utilization and charge separation of Ag@AgBr/BiVO4/Co3O4. The radical trapping experiments and EPR demonstrated that both superoxide radical (O2−) and holes (h+) were main active species for organics photodegradation. In summary, this work not only constructed a highly efficient Z-scheme structured visible-light photocatalyst, but also provided a new method to diminish the photo-carriers recombination by pre-separation channel and hole-sink effects.Graphical abstractGraphical abstract for this article
       
  • One-step low-temperature synthesis of 0D CeO2 quantum dots/2D BiOX (X =
           Cl, Br) nanoplates heterojunctions for highly boosting photo-oxidation and
           reduction ability
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Jian Yang, Yujun Liang, Kai Li, Gui Yang, Shu Yin 0D/2D heterojunctions, especially quantum dots (QDs)/nanoplates have attracted noteworthy attention for use of the high charge mobility of photoinduced electrons and holes. Herein, we report a novel one-step low-temperature route for the controlled synthesis of CeO2 QDs/BiOX (X = Cl, Br) nanoplates heterojunctions with the self-created in-built Ce4+/Ce3+ redox centers. The as-prepared heterojunctions exhibited outstanding photocatalytic abilities not only for the oxidation of tetracycline (TC) but also for the reduction of hexavalent chromium (Cr6+) although under 5 W white LED light irradiation. The considerably enhanced capabilities were attributed to the improvement of light absorption and the highly effective transfer and separation of photoexcited carriers, which encouraged by the strong synergistic effects of inner Ce4+/Ce3+ redox centers and the formation of intimately contacted interface between CeO2 QDs and BiOX nanoplates. Meanwhile, the likely degradation pathway of TC was proposed on the basis of the intermediate products detected by GC–MS, and the appearance photocatalytic mechanisms were also discussed in detail. This work could open new possibilities to provide some insight into a facile, energy saving and environmental friendly pathway for synthesizing versatile 0D/2D Bi-based heterojunction materials with high photocatalytic performance.Graphical abstractGraphical abstract for this article
       
  • Photo-assisted methanol synthesis via CO2 reduction under ambient pressure
           over plasmonic Cu/ZnO catalysts
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Zhou-jun Wang, Hui Song, Hong Pang, Yanxiao Ning, Thang Duy Dao, Zhuan Wang, Hailong Chen, Yuxiang Weng, Qiang Fu, Tadaaki Nagao, Yunming Fang, Jinhua Ye Methanol synthesis via carbon dioxide (CO2) reduction is challenging and important because this technology can convert CO2 by solar- or wind-generated hydrogen into liquid fuel. The present work introduces the visible light as an external stimulus and for the first time demonstrates that methanol synthesis over Cu/ZnO catalysts can be effectively promoted by solar energy under atmospheric pressure. Experimental and theoretical studies document that hot electrons were photo-excited by localized surface plasmon resonance (LSPR) on Cu nanoparticles and such photo-excited hot electrons could transfer to ZnO through the metal-support interfaces. The hot electrons on Cu and ZnO synergistically facilitated the activation of reaction intermediates. Consequently, the activation energy was reduced by 40% and the methanol synthesis activity was promoted by 54%. This work provides a new strategy towards synthesis of liquid fuel via CO2 reduction under low pressure and sheds new light on the mechanism of photo-mediated catalysis.Graphical abstractGraphical abstract for this article
       
  • Visible-light photocatalysis accelerates As(III) release and oxidation
           from arsenic-containing sludge
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Hongbo Lu, Xueming Liu, Feng Liu, Zhengping Hao, Jing Zhang, Zhang Lin, Yvonne Barnett, Gang Pan Arsenic containing sludge, a product of the treatment of acid smelting wastewater, is susceptible to temperature, pH, co-existing salt ions and organic matter, which might lead to the release of arsenic ions into the environment. Here, we studied the effect of visible light on the dissolution and oxidation of arsenic sulfide sludge (ASS) sampled from a smelting plant. Results show that by exposure to visible light, both the release of As(III) ions from ASS and the oxidation of As(III) into As(V) were markedly accelerated. Electron paramagnetic resonance (EPR) and free radical quenching experiments revealed that ASS acts as a semiconductor photocatalyst to produce hydroxide and superoxide free radicals under visible light. At pH 7 and 11, both the dissolution and the oxidation of the sludge are directly accelerated by O2¯. At pH 3, the dissolution of the sludge is promoted by both O2¯ and OH, while the oxidation of As(III) is mainly controlled by OH. In addition, the solid phase of ASS was transformed to sulfur (S8) which favored the aggregation and precipitation of the sludge. The transformation was affected by the generation of intermediate sulfur species and sulfur-containing free radicals, as determined by ion chromatography and low-temperature EPR, respectively. A photocatalytic oxidation-based model is proposed to underpin the As(III) release and oxidation behavior of ASS under visible light conditions. This study helps to predict the fate of ASS deposited in the environment in a range of natural and engineered settings.Graphical abstractGraphical abstract for this article
       
  • Reforming of tar from biomass gasification in a hybrid catalysis-plasma
           system: A review
    • Abstract: Publication date: 5 August 2019Source: Applied Catalysis B: Environmental, Volume 250Author(s): Lina Liu, Zhikun Zhang, Sonali Das, Sibudjing Kawi The generation of tar in biomass gasification is highly undesirable since the condensation and agglomeration of tar causes clogging and contamination of downstream equipment, leading to low energy efficiency and high maintenance cost. Currently, the most widely used methods for tar reforming are catalytic reforming and plasma reforming. However, the main drawbacks for these two processes are: (i) the rapid catalyst deactivation caused by poisoning, sintering and coke deposition for catalytic reforming, and (ii) low energy efficiency, low selectivity of syngas and the formation of undesirable byproducts for plasma reforming. Recently, therefore, the hybrid plasma-catalysis system has attracted much attention for tar reforming, since it can overcome the above-mentioned drawbacks and generate a synergy effect. The addition of catalyst in plasma could change the discharge properties of plasma, and the plasma could also modify the catalyst property and change the status of reactants. At present, very few review articles have reported and compared the performances of tar reforming in the plasma-only, catalysis-only and hybrid plasma-catalysis system. Therefore, this review paper focus on: (i) the deactivation characteristics and modification methods of steam-reforming catalysts, as well as the mechanism of tar catalytic reforming; (ii) the performance of tar reforming in various plasma reactors and the reaction mechanism based on the analysis of byproducts and energetic plasma species; and (iii) the possible synergistic effect of plasma and heterogeneous catalyst in a hybrid plasma-catalysis system caused by the multiple interactions of plasma and catalysts.Graphical abstractGraphical abstract for this article
       
  • Positive effects of K+ in hybrid CoMn-K and Pd/Ba/Al2O3 catalysts for NOx
           storage and reduction
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Zhifeng Bai, Bingbing Chen, Qi Zhao, Chuan Shi, Mark Crocker CoMn-K was mechanically mixed with a Pd/Ba/Al2O3 catalyst to enhance its NOx storage and reduction properties. The Pd/Ba/Al2O3 and CoMn-K mixture showed a synergetic effect with respect to NOx storage capacity and improved NOx reduction ability. The addition of K+ ions promoted the catalytic performance by increasing NO oxidation activity and therefore NOx storage via the creation of active surface oxygen species on the catalysts. The stored NOx reduction by H2 was also improved, being ascribed to the fact that Pd was mainly present as Pd0 due to the electronic interactions between Pd and K+ ions. NOx conversions and N2 selectivity at low temperatures (80–200 °C) could be further enhanced by assistance of non-thermal plasma in rich phase.Graphical abstractGraphical abstract for this article
       
  • Advances in bromate reduction by heterogeneous photocatalysis: The use of
           a static mixer as photocatalyst support
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Daniela F.S. Morais, Rui A.R. Boaventura, Francisca C. Moreira, Vítor J.P. Vilar This study focuses on bromate (BrO3−) removal from pure aqueous solutions by heterogeneous photocatalysis using a stainless steel Kenics® static mixer (SM) as support for the stabilization of TiO2-P25 thin films. The SM was assembled in a tubular photoreactor coupled to a compound parabolic collector (CPC) for light capture. The effect of the following parameters on the BrO3− photocatalytic reduction rate was assessed: SM treatment before TiO2-P25 deposition, number of TiO2-P25 layers deposited by dip coating, position of the SM during the coating procedure, solution pH, solution temperature, dissolved oxygen (DO) content, and addition of formic acid (HCOOH) as organic sacrificial agent. Furthermore, the TiO2-P25 films were characterized and their stability was evaluated. Higher BrO3− photocatalytic reduction rates were attained for: the thermally pre-treated SM, 6 TiO2-P25 layers, the vertically positioned SM during coating, acidic pH, and higher temperatures. The DO had a negligible effect for pH values below 5.5 and a negative effect for higher pH values. The HCOOH declined the BrO3− photocatalytic reduction rates when an initial [HCOOH]:[BrO3−] molar ratio of 3:1 was applied and had a null influence when used in lower amounts. The generated TiO2-P25 films proved to be stable.Graphical abstractGraphical abstract for this article
       
  • A novel electro-catalytic membrane contactor for improving the efficiency
           of ozone on wastewater treatment
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Kuiling Li, Lili Xu, Yong Zhang, Aixin Cao, Yujue Wang, Haiou Huang, Jun Wang A novel electro-catalytic membrane contactor was designed to break the two constrains in O3 wastewater treatment technology simultaneously: the mass transfer of O3-water and the decomposition rate of O3 into OH. In the electro-catalytic membrane contact ozonation (ECMCO) process, O2 and O3, in the gas chamber, diffuse through the hydrophobic membrane into the water phase; O2 is electro-reduced to H2O2 that catalyzes O3 producing OH to degrade organic compounds rapidly. The removal rate of nitrobenzene (NB) was significantly improved by the combination of membrane contactor and electro-catalytic process. The removal rates of NB in 120 min were 85%, 55% and 23% for ECMCO, membrane contact ozonation and electrolysis, respectively. O3 concentration and current density had positive effects on the removal of NB, which was related to the accumulated H2O2 concentration in aqueous phase. Gas flow had slight positive effects on NB removal when it was lower than 50 mL/min. The pH of the feed may affect the production and the form of H2O2 and hence the removal of NB. The highest removal rate in 120 min was up to 95.7% at the initial pH of 4.5. Mass transfer and electrolysis are synthetic in ECMCO process. On one hand, the mass transfer of O3 increased by 2 times due to the electro-catalytic production of H2O2. On the other hand, the existence of O3 promoted the production of H2O2. ECMCO has great potential on promoting mass transfer and decomposition of O3 into OH for the industrial application of O3.Graphical abstractGraphical abstract for this article
       
  • Atomically dispersed Fe-N-P-C complex electrocatalysts for superior oxygen
           reduction
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Yahao Li, Bingxu Chen, Xuezhi Duan, Shuangming Chen, Daobin Liu, Ketao Zang, Rui Si, Fengliu Lou, Xuehang Wang, Magnus Rønning, Li Song, Jun Luo, De Chen Development of cost-effective electrocatalysts as an alternative to platinum for oxygen reduction reaction (ORR) is of great significance for boosting the applications of green energy devices such as fuel cells and metal-air batteries. Here we report a nitrogen and phosphorus tri-doped hierarchically porous carbon supported highly cost-effective, efficient and durable Fe single-site electrocatalyst derived from biomass. Combined aberration-corrected HAADF-STEM, XPS and XAFS measurements and theoretical calculations reveal the atomically dispersed Fe-N-P-C-O complex as the dominant active sites for ORR. This work also shows the design principle for enhancing the ORR activity of single Fe site catalysts with higher Fe charge, which can be manipulated by the coordinated structure in the active centre. Theoretical calculations reveal that the main effective sites are singleN-P-O-Fe-O centers, where the associated P-O-Fe bond can significantly lower the stability of strongly adsorbed O* and OH* on the catalytically active sites and thus give rise to enhanced ORR performance. The insights reported here open a new avenue for constructing highly efficient molecule-like heterogeneous catalysts in electrochemical energy technologies.Graphical abstractThe P-O-Fe bond and the redox cycle between N-P-O-Fe-O and N-P-O-Fe-O2 on atomically dispersed Fe-N-P-C complex catalyst prepared directly form woody biomass efficiently reduced adsorption strength of OH*, which leads to outstanding ORR activity.Graphical abstract for this article
       
  • The role of defect sites and oxophilicity of the support on the phenol
           hydrodeoxygenation reaction
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Camila A. Teles, Priscilla M. de Souza, Adriano Henrique Braga, Raimundo C. Rabelo-Neto, Alejandra Teran, Gary Jacobs, Daniel E. Resasco, Fabio B. Noronha This work studies the effect of support defect sites on the performance of Pd/CexZr1-xO2 (x = 0.00; 0.25; 0.50; 0.75; 0.90) catalysts for the hydrodeoxygenation of phenol in the gas phase at 573 K. The activity and selectivity for hydrodeoxygenation of phenol depends significantly on the support used. Increasing the Zr content from x = 0.0 to 0.5, the reaction rate for hydrodeoxygenation and the selectivity to benzene remains very low. However, upon increasing the Zr content above x = 0.5 a sudden jump in reaction rate and selectivity to benzene is observed. Interestingly, this activity and selectivity boost has no direct correlation with the density of acid sites or the concentration of defects on the support. Rather, the selectivity to deoxygenated products is found to depend on the oxophilicity of the support. Increasing the Zr content enhances the strength of the interaction between the O of the carbonyl group and the oxophilic site. It is proposed that the oxophilicity of these catalysts is related to the structure of the CexZr1-xO2 solid solution formed. In addition, it is observed that the degree of deactivation during the reaction also depends on the Ce/Zr molar ratio of the support. Pd/ZrO2, Pd/Ce0.10Zr0.90O2 and Pd/Ce0.25Zr0.75O2 catalysts readily deactivate during reaction, whereas the phenol conversion only slightly decreases for Pd/CeO2, Pd/Ce0.75Zr0.25O2 and Pd/Ce0.50Zr0.50O2 catalysts. The results reveal that the density of Zr species on the surface is responsible for catalyst deactivation. The stronger adsorption between the oxygen from the phenol with Zr cations resulted in an accumulation of O-containing byproducts and catalyst deactivation.Graphical abstractGraphical abstract for this article
       
  • Efficient evolution of reactive oxygen species over the coordinated
           π-delocalization g-C3N4 with favorable charge transfer for sustainable
           pollutant elimination
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Jingjie Liu, Chuanbao Xiong, Shujuan Jiang, Xi Wu, Shaoqing Song Reactive oxygen species (ROS) as efficient and green oxidants can be generated through various catalytic methods, which is important for environmental chemistry and chemical engineering. Here we construct an efficient photocatalytic system to evolve ROS for environmental purification. In the work, the coordinated g-C3N4 photocatalysts (Cu/C3N4) are designed by interacting N 2p lone electrons at vacancy site of tri-s-triazine polymer with 3d orbits of Cu2+, resulting in the extended π-delocalization structure of g-C3N4. Experimental and theoretical calculations confirm that the extended π-delocalization structure of Cu/C3N4 strengthens the light capturing capability from ultraviolet to near infrared light, favors the charge transfer from N 2p of C3-N to the linked C, and Cu atoms. As a result, the efficient evolution of ROS including O2− (13 μmol L−1 h−1), and H2O2 (550 μmol L−1 h−1) can be completed over Cu/C3N4 photocatalysts. Cu/C3N4 photocatalysts results in a highly efficient generation of ROS and also exhibited a sustainable removal efficiency for NO, and HCHO, which demonstrates a promising application in the field of environmental purification.Graphical abstractGraphical abstract for this article
       
  • Sea-urchin-structure g-C3N4 with narrow bandgap (˜2.0 eV) for efficient
           overall water splitting under visible light irradiation
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Yunxiong Zeng, Hao Li, Jinming Luo, Jili Yuan, Longlu Wang, Chengbin Liu, Yingchun Xia, Meijun Liu, Shenglian Luo, Tao Cai, Su Liu, John C. Crittenden A broad bandgap and detrimental recombination of photoexcited h+-e− pairs are fatal deficiencies for using the g-C3N4 visible light water splitting. Herein, a sea-urchin-structure g-C3N4 (CNSC) with ∼2.0 eV bandgap was prepared using a hydrothermal strategy. It is important to note that CNSC can efficiently suppress h+-e− pair recombination and has a narrow bandgap which can utilize more visible light. Conventional g-C3N4 has a ∼2.7 eV bandgap and valence band (VB) potential of +1.83 V vs. NHE but the VB of CNSC is +1.55 V. As a result, CNSC does not create H2O2, which can passivate g-C3N4. Density functional theory (DFT) confirms that CN, CO, and OH groups in the CNSC shift the d-band centre of Pt closer to Fermi level, leading to better stabilization of adsorbate and higher catalytic performance. Photo-depositing Pt on the CNSC, 3 wt% Pt/CNSC produces H2 and O2 evolution rate (HER and OER) of 41.5 and 20.3 μmol g-1 h-1 (apparent quantum efficiency: 0.43% at 420 ± 10 nm), respectively, 30 times greater than HER of 2 wt% Pt/bulk g-C3N4 in overall water splitting under visible-light (λ ≥ 420 nm). This work provides an innovative approach to construct hierarchical nanostructure g-C3N4 with narrow bandgap and paves the pathway for development of water splitting photocatalysts.Graphical abstractGraphical abstract for this article
       
  • Defective borate-decorated polymer carbon nitride: Enhanced photocatalytic
           NO removal, synergy effect and reaction pathway
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Jiwu Cao, Jingyuan Zhang, Xing’an Dong, Hailu Fu, Xianming Zhang, Xiaoshu Lv, Yuhan Li, Guangming Jiang This work developed one effective approach to introduce both the N defect and borate group on polymer carbon nitride (PCN) by facilely immersing it in a NaBH4 aqueous solution, and simultaneously control their number by varying the NaBH4 concentration. The resultant defective borate-decorated PCN (denoted as X-B-PCN, X refers to the used NaBH4 concentration) shows highly efficient in removing the ppb-level NO from an air flow under visible light irradiation. The removal efficiency displays a volcano-like variation with X, and the peak one reaches 44.1% by 1.32-B-PCN. The comparative studies on the optical property, the yield of active radicals, and the oxygen adsorption behaviors of PCN and X-B-PCN reveal that the synergy of N defect and borate decoration promotes the light absorbance, charge carrier separation and molecular oxygen adsorption, all of which contribute to an enhanced generation of the O2− and OH radicals for a better photocatalytic performance. The relative contribution of N defect to borate group in this synergy also depends on the X value, but the borate group always takes the major role. The in-situ DRIFTS investigation reveals that the NO is converted to nitrate. Overall, our work offered one viable strategy to make full use of the defect and group decoration for photocatalytic performance optimization of the PCN-based materials.Graphical abstractGraphical abstract for this article
       
  • Preparation of stable and highly active Ni/CeO2 catalysts by glow
           discharge plasma technique for glycerol steam reforming
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Bo Wang, Yingying Xiong, Yaoyao Han, Jingping Hong, Yuhua Zhang, Jinlin Li, Fangli Jing, Wei Chu CeO2 nanorods supported nickel catalysts were prepared by wetness impregnation method, using nickel nitrate and nickel chloride as nickel sources. The dried catalyst precursors were decomposed either by thermal calcination or glow discharge plasma technique. The effects of precursor decomposition methods and nickel sources on the catalytic performance of glycerol steam reforming were then investigated. Characterization and catalytic results showed that glow discharge plasma treatment instead of thermal calcination enhanced the nickel dispersion, improved the Ni-Ce interaction and led to the formation of Ni-O-Ce composite, which could both enhance the H2 selectivity and restrain the coke deposition during reaction. Thus, no deactivation was observed on the two plasma treated catalysts throughout the tests. Nickel source may influence both rate of particle sintering and carbonaceous deposition during reaction; fast nickel sintering but slower coke deposition was found on the catalysts prepared from nickel chloride, and coke deposition was more detrimental to active sites decrease than nickel sintering.Graphical abstractGraphical abstract for this article
       
  • Distinctive ternary CdS/Ni2P/g-C3N4 composite for overall water splitting:
           Ni2P accelerating separation of photocarriers
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Heng He, Jing Cao, Minna Guo, Haili Lin, Jinfeng Zhang, Yong Chen, Shifu Chen Efficient overall water splitting over semiconductor photocatalyst is vital but difficult for resolving the energy and environmental crises. In this report, a novel transition metal phosphide Ni2P-based ternary CdS/Ni2P/g-C3N4 composite was constructed for achieving efficient overall water splitting activity under visible light (λ > 420 nm). The H2 and O2 evolution ratios are 15.56 and 7.75 μmol·g–1 h–1 over CdS/Ni2P/g-C3N4 with 3 wt% Ni2P, respectively, which is 4.02 times higher than that of binary type II CdS/g-C3N4. The separation efficiency of photocarriers of CdS/Ni2P/g-C3N4 is enhanced through greatly speeding up the transfer efficiency of electrons from the conduction band of g-C3N4 to that of CdS using Ni2P as electron-bridge, proved by the photoluminescence, transient photocurrent measurements and electrochemical impendence spectroscopy. The significant finding of this paper sheds light on the important role of transition metal phosphide as electron-bridge to connect the two conduction bands of type II semiconductor heterojuction for strengthening the separation efficiency of photocarriers.Graphical abstractDistinctive ternary CdS/Ni2P/g-C3N4 photocatalyst achieved outstanding photocatalytic activity for overall water splitting via the Ni2P electron-bridge to separate the photocarriers efficiently.Graphical abstract for this article
       
  • Facile growth of compositionally tuned copper vanadate nanostructured thin
           films for efficient photoelectrochemical water splitting
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Shankara S. Kalanur, Hyungtak Seo Copper vanadates are considered as one of the most promising photoanode materials for photoelectrochemical (PEC) water splitting owing to their narrow bandgap, stoichiometry-dependent optical and electrical properties, and high stability. However, for technological applications, it is imperative to develop stoichiometrically and structurally tuned copper vanadates for improved performance. In this study, we developed a facile and one-step hydrothermal method for the synthesis of Cu2V2O7 nanoplates, Cu5V2O10 nanorods, and Cu11V6O26 micropillars on a fluorine-doped tin oxide substrate without using a seed layer. The presence of urea during the hydrothermal synthesis significantly affected the film formation and morphology of the copper vanadates. The crystallographic, chemical, and electrochemical properties of the synthesized copper vanadates were investigated. The optimized Cu2V2O7, Cu5V2O10, and Cu11V6O26 electrodes exhibited the highest photocurrent densities of ˜0.41, 0.27, and 0.076 mA cm−2 (at 1.23 V vs. reversible hydrogen electrode under 1-sun illumination) and incident photon to current efficiency values of ˜24%, 18%, and 7.5% (at 300 nm), respectively. The band edge positions of Cu2V2O7, Cu5V2O10, and Cu11V6O26 were estimated on the basis of the spectroscopic and electrochemical results. The synthesis scheme and valuable insights provided in this work can be used for the development of chemically and morphologically optimized copper vanadates for efficient PEC water splitting.Graphical abstractGraphical abstract for this article
       
  • Oxomolybdate anchored on copper for electrocatalytic hydrogen production
           over the entire pH range
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Xiaolong Zhang, Ying Zhang, Fengwang Li, Christopher D. Easton, Alan M. Bond, Jie Zhang Uniting the advantages of molecular and heterogeneous catalysts, a continuing effort in heterogeneous catalysis, has often proved to be challenging. This work introduces a facile strategy to obtain molybdenum-oxo functional groups strongly anchored on metallic copper support through in situ electrochemical reduction of a cuprous oxomolybdate thin film resulting from electroless plating. The oxomolybdate modified copper electrode exhibits enzyme-like activity and excellent stability for the hydrogen evolution reaction over the entire pH range, together with excellent mechanical properties and cost effectiveness that are needed for commercial applications, including seawater electrolysis. In situ Fourier transformed ac voltammetric study revealed two underlying MoIV/III and MoIII/II processes that are responsible for the high catalytic activity of the material. This study opens up a new avenue for designing advanced heterogeneous catalysts for a greener future using a broad range of oxometalates.Graphical abstractGraphical abstract for this article
       
  • Evolution of zincian malachite synthesis by low temperature
           co-precipitation and its catalytic impact on the methanol synthesis
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Leon Zwiener, Frank Girgsdies, Daniel Brennecke, Detre Teschner, Albert G.F. Machoke, Robert Schlögl, Elias Frei Low temperature co-precipitation enabled, for the first time, the preparation of phase pure zincian malachite precursors with Zn contents of up to 31 at.-%. The high Zn content was beneficial for maximizing the dispersion of Cu and oxygen defect sites on the ZnO surface. Further, an increase of the Zn loading from 10 to 31 at.-% doubled the specific surface areas obtained from N2O-RFC (Reactive Frontal Chromatography) and H2-TA (Transient Adsorption). As the Zn content was increased from 10 to 31 at.-%, the apparent activation energy for methanol formation was strongly decreased. Furthermore, water formation was reduced indicating a retardation of the rWGS in favor of methanol formation at high Zn loadings. Additionally, compared to high temperature co-precipitation, low temperature precipitated catalysts exhibited increased catalytic activities.Graphical abstractGraphical abstract for this article
       
  • Performance and kinetic modelling of photolytic and photocatalytic
           ozonation for enhanced micropollutants removal in municipal wastewaters
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Danilo Bertagna Silva, Alberto Cruz-Alcalde, Carmen Sans, Jaime Giménez, Santiago Esplugas In this work, the performances of ozonation, photolytic ozonation (UV-C/O3), and photocatalytic ozonation (UV-A/TiO2/O3) in degrading ozone recalcitrant micropollutants in four different real domestic wastewaters were evaluated in semi-continuous operation, together with the influence of water matrices in the ozone mass transfer and pollutant degradation rates. The OH exposure per consumed ozone ratio, defined as ROH,O3, was applied for single ozonation and modified for light-assisted ozonation processes to evaluate and compare the contribution of radical pathway on micropollutants abatement for the different wastewaters studied. ROH,O3 plots presented good fitting (R2 > 0.95) in two stages, corresponding to different ozone mass transfer regimes, for all cases. Light-assisted ozonation attained higher pollutant degradation for all water matrices compared to single ozonation, although the performance of UV-assisted processes was more sensitive to matrix factors like composition and turbidity. Moreover, the improvement brought by both light-based processes on ROHO3 values mainly took place during the second stage. Thus, photocatalytic ozonation reached ROHO3 values higher than double for all wastewaters, compared with single ozonation (between 105% and 127% increase). These values represent a saving of almost half of the overall ozone needs (42%) for the same ozone recalcitrant micropollutant depletion, although it would require the adoption of higher ozone doses than the currently employed for ozonation in wastewater treatment plants.Graphical abstractGraphical abstract for this article
       
  • Photoresponsive nanostructure assisted green synthesis of organics and
           polymers
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Maosong Liu, Tingyu Peng, Henan Li, Long Zhao, Yuanhua Sang, Qunwei Feng, Li Xu, Yinhua Jiang, Hong Liu, Jianming Zhang Solar light is believed to be the most sustainable and clean energy source. In line with the concept of green chemistry, the use of solar energy has been a formidable impetus toward the development of novel photo-based synthetic technologies to drive various chemical reactions. Photosynthesis is a promising route to achieve a wide array of chemical transformations with distinctive energy and environmental merits which are usually inaccessible with conventional thermal processes. Photoinduced organic synthesis, as one important branch of photosynthesis, has attracted increasingly attentions to meet the growing-up environmental and energy concerns. Highly photoresponsive nanoparticles (NPs), such as semiconductors, can generate photoexcited charge carriers, i.e. electron-hole pairs, upon photon absorption, which can favor a vast number of reactions, demonstrating unique advantages including the easily recycling and reuse, the use of mild reaction conditions and the generation of high-purity products devoid of contaminants. This review article highlights recent representative advances in heterogenous photocatalytic organic synthesis, mainly including CO2 reduction, organic transform and free radical polymerization; in particular, for the first time, the achievements on photoresponsive NP initiated free radical polymerizations are summarized here. We conclude this review by proposing several interesting research directions and future challenges with the hope that it can serve as a good reference for researchers in nanomaterials and catalysis.Graphical abstractGraphical abstract for this article
       
  • Cu dendrites induced by the Anderson-type polyoxometalate NiMo6O24 as a
           promising electrocatalyst for enhanced hydrogen evolution
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Dejin Zang, Yichao Huang, Qi Li, Yajie Tang, Yongge Wei The design and synthesis of specific functional complex materials as desired catalysts for improved energy conversion and storage are of great importance and with grand challenges. Here, a facile synthesis strategy of Anderson POMs supported Cu dendrites toward electrochemical hydrogen evolution reaction with dramatically decreased overpotential under acidic aqueous condition is established in this work. We present the preparation of well crystallized Cu dendrites through co-electrodeposition on TiO2 array with Anderson-type POM NiMo6O24. Structural and state of valence investigation of the as-obtained electrocatalyst (NiMo6O24@Cu/TNA) evidence the specific morphology tunability and modification of Cu dendrites surfaces. During HER course, NiMo6O24 can improve the H+ transfer and further help the H atom absorption which remedies the weakness of insufficient H atom absorption ability of Cu along with its strong electron transfer lowering overpotential upon HER. Therefore, HER with NiMo6O24@Cu/TNA is considerably enhanced by decreasing related overpotential of 130 mV compared to porous Cu foam. The modification of NiMo6O24 endowed catalysts strong corrosion resistance assuring long term stability. Hence, the proposed strategy possesses improved activity and long term stability upon HER with NiMo6O24@Cu/TNA as electrocatalyst. Depending on the diversity of POMs, the current feasible and reliable heterogeneous electrocatalysts design with POMs would inspire more effective, low-cost strategies for energy conversion and open the pathway for large scale production.
       
  • Catalytic tar removal using
           TiO2/NiWO4-Ni5TiO7 films
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Jing Xu, Philip Holthaus, Nianjun Yang, Siyu Jiang, Alwin Heupel, Holger Schönherr, Bing Yang, Wolfgang Krumm, Xin Jiang One-dimensional nickel catalysts are more promising than nickel powders for catalytic tar removal from biomass gasification, originating from their unique morphologies and higher specific surfaces. Herein, we demonstrate the application of a Ti supported multilayer system, namely a TiO2/NiWO4-Ni5TiO7 film, for catalytic tar removal. This film is synthesized via plasma electrolytic oxidation (PEO) combined with subsequently impregnation and annealing. The surface morphology and the size of as-synthesized Ni5TiO7 nanowires are determined mainly by used electrolytes during PEO processes. For catalytic tar removal, a fixed bed reactor is utilized and naphthalene is chosen as a model tar. This TiO2/NiWO4-Ni5TiO7 film exhibits higher efficiency than thermal cracking as well as long-term stability towards catalytic steam reformation of naphthalene. A naphthalene conversion rate of 63% is achieved at 800 °C with a short residence time of 0.34 s and a high tar load of 75 g mN−3. Such a TiO2-NiWO4/Ni5TiO7 film is thus promising for future tar removal from biomass gasification in the industry.Graphical abstractGraphical abstract for this article
       
  • Bottom-up MOF-intermediated synthesis of 3D hierarchical flower-like
           cobalt-based homobimetallic phophide composed of ultrathin nanosheets for
           highly efficient oxygen evolution reaction
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Guoliang Li, Xiaobing Zhang, He Zhang, Chunyang Liao, Guibin Jiang In demand of implementing the replacement of fossil fuels, efficient oxygen evolution reaction (OER) catalysts are required in producing clean and low-cost hydrogen fuels via water splitting, the urgency and great necessity of which make it one of the greatest challenges for scientists and engineers concerned with research on energy issues. A novel bottom-up one-pot solvothermal strategy followed by low-temperature phosphorization was developed to prepare 3D hierarchical flower-like materials composed of ultrathin cobalt based bimetallic phosphide nanosheets (CoM-P-3DHFLMs) as cost-effective OER electrocatalysts, which are highly efficient and durable. Due to their unique structural and compositional advantages, the CoM-P-3DHFLMs not only achieve satisfying electrocatalytic efficiencies (η@10 mA cm−2 = 292 mV, 318 mV, and 307 mV for CoNi-, CoMn-, and CoCu-P-3DHFLM, respectively) comparable to IrO2 and RuO2 counterparts, but also exhibit long-term stability with subtle decrement after 10 h. The advantages of high efficiency, good stability, and free of noble metal make the as-prepared 3DHFLMs promising candidates for OER.Graphical abstractGraphical abstract for this article
       
  • Enhancing water splitting activity by protecting hydrogen evolution
           activity site from poisoning of oxygen species
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Bin Tian, Wei Gao, Xiaofeng Ning, Yuqi Wu, Gongxuan Lu Photocatalytic hydrogen evolution via water splitting is considered as one of ideal ways to solar energy conversion and storage, however, the low energy conversion efficiency and weak catalyst stability are still two main obstacles to overcome. In our present study, we found hydrogen peroxide formed during water splitting affect deleteriously the hydrogen evolution activity of catalyst due to the occupation of active sites on catalyst. Such a negative effect of hydrogen peroxide on hydrogen generation can be prohibited by introduction of superoxide dismutase (SOD), which is able to decompose the adsorbed hydrogen peroxide. The in-situ synthesized Sn4+ center over SnO photocatalyst can catalytically decompose hydrogen peroxide more efficiently than SOD, and as a result, Sn4+/SnO photocatalyst exhibited higher activity for over-all water splitting and better stability. By taking advantage of Sn4+ catalytic properties for hydrogen peroxide, the rate of H2 evolution reached 18.3 μmol·g−1·h−1 and the corresponding AQE of 0.18% at 420nm over Sn4+/SnO catalyst under visible light irradiation without noble metal loading.Graphical abstractThe in-situ synthesized Sn4+ center over SnO photocatalyst can catalytically decompose hydrogen peroxide, and as a result, the poisoning of oxygen species on hydrogen evolution is inhibited. Sn4+/SnO photocatalyst exhibited higher activity for over-all water splitting and better stability. The rate of H2 evolution reached 18.3 μmol·g−1·h−1, and the corresponding AQE at 420nm achieved 0.18% over Sn4+/SnO catalyst under visible light irradiation without noble metal loading.Graphical abstract for this article
       
  • Enhanced photocatalytic NOx oxidation and storage under visible-light
           irradiation by anchoring Fe3O4 nanoparticles on mesoporous graphitic
           carbon nitride (mpg-C3N4)
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Muhammad Irfan, Melike Sevim, Yusuf Koçak, Merve Balci, Önder Metin, Emrah Ozensoy Several mesoporous graphitic carbon nitride (mpg-C3N4) photocatalysts were synthesized by using a hard-templating method comprising thermal polycondensation of guanidine hydrochloride over silica spheres at three different temperatures (450, 500 and 550 ℃). After structural characterization of these mpg-C3N4 photocatalysts, they were tested in NO(g) photo-oxidation under visible (VIS) light. The effects of polycondensation temperature on the structure and photocatalytic performance of mpg-C3N4 in NO photo-oxidation were studied. The results revealed that polycondensation temperature has a dramatic effect on the photocatalytic activity of mpg-C3N4 in NO photo-oxidation, where mpg-C3N4 synthesized at 500 ℃ (mpg-CN500) showed the best performance in NOx abatement as well as a high selectivity towards solid state NOx storage under VIS light illumination. Photocatalytic performance of the mpg-CN500 was further enhanced by the anchoring of 8.0 ± 0.5 wt.% Fe3O4 nanoparticles (NPs) on it. Fe3O4/mpg-CN500 photocatalyst showed both high activity and high selectivity along with extended reusability without a need for a regeneration step. Enhanced photocatalytic NOx oxidation and storage efficiency of Fe3O4/mpg-CN500 photocatalyst was attributed to their mesoporous structure, high surface area and slow electron-hole recombination kinetics, efficient electron-hole separation and facile electron transfer from mpg-CN500 to Fe3O4 domains enhancing photocatalytic O2 reduction, while simultaneously suppressing nitrate photo-reduction and decomposition to NO2(g).Graphical abstractGraphical abstract for this article
       
  • Ultrathin PdAg single-crystalline nanowires enhance ethanol oxidation
           electrocatalysis
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Hao Lv, Yang Wang, Aaron Lopes, Dongdong Xu, Ben Liu Rational design and synthesis of highly efficient nanocatalysts towards electrochemical ethanol oxidation reaction (EOR) are of great importance for practical applications in direct ethanol fuel cells. Nanoengineering the nanostructures and compositions of EOR electrocatalysts has been of significnat interest because these paratmeters can enhance electrocatalytic kinetics and performance in the EOR. This article reports a synergistic EOR catalyst with remarkably enhanced electrochemical performance based on 3-nm-thick bimetallic PdAg single-crystalline nanowires. Kinetically stable yet thermodynamically unfavorable ultrathin PdAg single-crystalline nanowires (sNWs) are epitaxially grown in situ along nanoconfined hexagonal mesophases directly self-assembled by amphiphilic surfactants of dioctadecyldimethylammonium chloride under optimal synthetic condtions in aqueous solution. Due to the ultrathin and ultralong nanostructure, single-crystalline feature with a high density of low-coordinate atomic steps, high Pd utilization efficiency, and incorporation of more oxophilic Ag with Pd, PdAg sNWs show enhanced mass activity of 2.84 A mgPd−1 and stability (retained 43% after 2500 cycles) in the EOR. The kinetic studies reveal that significant enhancement in EOR performance can be ascribed to the synergic electronic and bifunctional effects of ultrathin PdAg sNWs.Graphical abstractGraphical abstract for this article
       
  • Mediating interaction strength between nickel and zirconia using a mixed
           oxide nanosheets interlayer for methane dry reforming
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Anup P. Tathod, Naseem Hayek, Dina Shpasser, David S.A. Simakov, Oz M. Gazit For many reactions balancing the degree of interaction between the metal catalyst and the underlying support material is pivotal for obtaining optimal catalytic performance. One important example is the reforming of methane contained in biogas, using CO2 as an oxidizer, to make syngas (H2 and CO). For this reaction to become industrially viable, the catalyst needs to be based on non-precious transition metals. Unfortunately, catalyst deactivation induced by metal sintering and coking remains a major challenge for this class of catalysts. Herein, we demonstrate the use of a ″surface phase oxide″ in the form of MgAl mixed oxide nanosheets (
       
  • Hierarchical microsphere of MoNi porous nanosheets as electrocatalyst and
           cocatalyst for hydrogen evolution reaction
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Linjing Yang, Lili Zeng, Hui Liu, Yunqie Deng, Ziqian Zhou, Jiayuan Yu, Hong Liu, Weijia Zhou In industrial water electrolysis cell, the electrocatalyst has a sluggish water dissociation kinetics leading to low electrocatalytic activity for the generation of H2 from water splitting. This work reports a hierarchical microsphere constructed by MoNi porous nanosheets derived from NiMoO4 microsphere, as a rapid Tafel-step-decided electrocatalyst towards hydrogen evolution reaction (HER). Consequently, the synthesized MoNi hierarchical microsphere (MoNi HM) electrocatalyst exhibits an onset potential of as small as −7 mV vs. RHE, an operating potential of 72 mV for 10 mA cm−2, and a low Tafel slope of 36.6 mV per decade in 1.0 M KOH. Furthermore, MoNi HM as cocatalyst and CdS nanowires as photocatalyst are physically mixed (MoNi HM/CdS NWs) and presentes a champion photocatalytic performance for H2 production with a prominent H2 generation rate of as high as 151.7 μmol mg-1 h−1 at λ > 420 nm light illumination. The large contact area between MoNi nanosheets and CdS nanowires endows the fast separation of photogenerated charge carriers to significantly facilitate the photocatalytic H2 production.Graphical abstractGraphical abstract for this article
       
  • Single-atom ruthenium based catalyst for enhanced hydrogen evolution
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Dewen Wang, Qun Li, Ce Han, Zhicai Xing, Xiurong Yang Ruthenium (Ru) as a cheaper alternative to Pt has been studied as a viable alternative for the hydrogen evolution reaction (HER) catalyst, however, no single-atom Ru catalyst has been reported for the HER electrocatalysis. Herein, we design and develop the first type of single-atom Ru based catalyst applied for the HER under pH-universal conditions. This binder-free catalyst consists of single Ru atoms anchored to the surface of MoS2 nanosheets array supported by a carbon cloth (Ru-MoS2/CC, Ru in Ru-MoS2: 0.37 wt%). The abundant dispersed single Ru atoms are highly catalytically active, and the MoS2 array supported 3D porous structure offers more opportunities for active sites and serves as co-catalysts for synergetic catalysis, with accompanying enhanced the electrical conductivity of this array-catalyst. Remarkably, the Ru-MoS2/CC exhibits extremely enhanced catalytic activity compared to that of MoS2/CC and possesses good long-term stability. Density functional theory calculations revealed that the improved catalytic activities stem from the synergistic effect between MoS2 and single-atom Ru. This discovery holds a great potential to accelerate the large-scale binder-free application of single Ru atoms in industry.Graphical abstractSingle-atom Ru based catalyst was developed for pH-universal hydrogen generation based on our theoretical predictions, whose performances are comparable to and better than those for Pt/C.Graphical abstract for this article
       
  • Cu2In2ZnS5/Gd2O2S:Tb for full solar spectrum photoreduction of Cr(VI) and
           CO2 from UV/vis to near-infrared light
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Xinjuan Liu, Baibai Liu, Lei Li, Zhihao Zhuge, Pengbin Chen, Can Li, Yinyan Gong, Lengyuan Niu, Junying Liu, Lei Lei, Chang Q. Sun Full solar spectrum active heterogenous photocatalysis for environmental applications remains highly challenging. Here we report the novel Cu2In2ZnS5/Gd2O2S:Tb (CG) hybrid photocatalysts via a facile solvothermal method for efficient Cr(VI) and CO2 reduction. The narrow band gap energies of the CG hybrid photocatalysts synthesized via a facile solvothermal method show excellent absorption and catalytic activity in the full solar spectrum. High Cr(VI) reduction rate of 90% and CH4 production rate of 57.73 μmol h−1 g−1 are achieved for CG hybrid photocatalyst with 1 wt.% Gd2O2S:Tb. The excellent performance is due to the fact that in the hybrid, Gd2O2S:Tb as cocatalyst, provides more active sites and inhibits the recombination of charge carriers due to the synergetic effect between Cu2In2ZnS5 and Gd2O2S:Tb, consequently improving the photocatalytic reduction activity.Graphical abstractGraphical abstract for this article
       
  • Design and scale-up of a Cr-free Fe-Al-Cu catalyst for hydrogen production
           from waste-derived synthesis gas
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Won-Jun Jang, Jae-Oh Shim, Kyung-Won Jeon, Hyun-Suk Na, Hak-Min Kim, Yeol-Lim Lee, Hyun-Seog Roh, Dae-Woon Jeong Herein, we have prepared a series of Cr-free Fe-Al-Cu catalysts by the homogeneous one-step co-precipitation method and examined their ability to promote the water gas shift (WGS) reaction and thus facilitate the production of hydrogen from waste-derived synthesis gas. The prepared catalysts are confirmed to possess γ-Fe2O3, which can be more easily transformed into Fe3O4 than α-Fe2O3. The surface area, Fe3O4 crystallite size, reducibility, and Cu dispersion of these catalysts significantly depend on the concentrations of metal precursor. The catalysts effectively promote the WGS reaction without facilitating undesirable side reactions, achieving efficient hydrogen production and high CO conversion. The characteristics of the best-performing sample are preserved when the production is scaled up by a factor of 40 and thus obtained large-scale Fe-Al-Cu catalyst exhibits excellent reducibility and high CO conversion. Both commercial Fe-Cr and large-scale Fe-Al-Cu catalysts achieve close-to-equilibrium CO conversions at a gas hourly space velocity (GHSV) of 3000 mL g−1 h−1, but the latter showed a higher conversion than the former at a GHSV of 40,057 mL g−1 h−1 owing to the promotional effect of Cu on the easier reducibility of Fe species and the formation of additional Cu active sites. Thus, we demonstrate the possibility of finding Cr-free alternatives and show that the reducibility, Fe3O4 crystallite size, and Cu dispersion of the best-performing catalyst could be maintained upon upscaling, which made this catalyst well suited for converting waste-derived synthesis gas into H2.Graphical abstractGraphical abstract for this article
       
  • Radio-frequency thermal plasma-induced novel chainmail-like core-shell
           MoO2 as highly stable catalyst for converting syngas to higher alcohols
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Jianli Li, Ruijue Hu, Hao Qu, Yue Su, Na Wang, Haiquan Su, Xiaojun Gu A novel core-shell catalyst with crystalline MoO2 core and chainmail-like amorphous MoOX shell (noted as MoO2-Pla) was prepared by radio-frequency induction thermal plasma method, and its catalytic performance for higher alcohols synthesis from syngas (CO and H2) was compared with that of the MoO2 catalysts synthesized by hydrothermal method and temperature programed reduction method (noted as MoO2-Hyd and MoO2-TPR). It was found that the chainmail-like shell formed under such extreme condition was both active to the reaction and inert to the thermal sintering, which was very fascinating and significantly different from those of the previous reported core-shell catalysts. The unusual amorphous species in the shell increased the CO conversion of MoO2-Pla catalyst by 109 and 213.5%, respectively, compared with MoO2-Hyd and MoO2-TPR. More importantly, the shell formed under such ultra-high temperature (over 3000 °C) and ultra-fast quenching process exhibited ultra-stable chainmail-like particle surface, which endowed the catalyst with high catalytic stability within 300 h of experimental determination. This work provided a new alternative strategy and method for the design of high activity and high stability catalysts.Graphical abstractGraphical abstract for this article
       
  • Noble-metal-free NiCu/CeO2 catalysts for H2
           generation from hydrous hydrazine
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Wooram Kang, Heng Guo, Arvind Varma The development of cost effective catalysts with high activity and 100% selectivity for hydrogen generation from the decomposition of hydrous hydrazine, a promising liquid-phase hydrogen carrier, is a critical challenge for the practical application of hydrous hydrazine to fuel cell vehicles. In this study, noble-metal-free NiCu/CeO2 bimetallic catalysts were readily synthesized using one-step solution combustion synthesis (SCS). The addition of Cu to Ni/CeO2 exhibited a synergistic effect to enhance the catalytic activity for the reaction. Catalyst characterization revealed that the improvement of catalytic performance is attributed to a combination of NiCu alloying, particle size of the active component, and formation of oxygen vacancy in the CeO2 lattice. The tailored 13 wt% Ni0.5Cu0.5/CeO2 catalyst exhibited 100% H2 selectivity in the temperature range 30–70 °C and 3.2-fold higher turnover frequency (TOF) of 1450.0 h−1 at 50 °C as compared to of the Ni/CeO2. This reactivity is also superior to that of most reported non-noble metal catalysts and is even comparable to noble metal-based catalysts.Graphical abstractGraphical abstract for this article
       
  • Engineering of activated carbon surface to enhance the catalytic activity
           of supported cobalt oxide nanoparticles in peroxymonosulfate activation
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Juan C. Espinosa, Premkumar Manickam-Periyaraman, Francisco Bernat-Quesada, Subramanian Sivanesan, Mercedes Álvaro, Hermenegildo García, Sergio Navalón Commercial activated carbon has been functionalized by chemical or thermal treatments to introduce surface oxygen functional groups able to anchor small cobalt nanoparticles with superior catalytic activity for peroxymonosulfate activation. The resulting activated carbon supports where characterized by combustion elemental analysis, Fourier-transformed infrared spectroscopy, Raman spectroscopy, isothermal N2 adsorption, temperature programmed desorption/mass spectrometry, X-ray diffraction and scanning electron microscopy. Activated carbon functionalization by nitric acid resulted the most appropriated method to provide a higher population of oxygenated functional groups able to anchor small cobalt nanoparticles. The catalytic activity of supported oxidized metal nanoparticles (4.7 ± 0.05 nm) was higher than analogous non-oxidized cobalt nanoparticles (2.9 ± 0.14 nm). The use of analogous supported oxidized iron or copper nanoparticles resulted in lower catalytic activity. Importantly, the supported oxidized cobalt nanoparticles at 0.2 wt% loading exhibit higher activity than benchmark catalysts such as unsupported Co3O4 solid or even homogeneous Co2+ ions. This is a reflection of the relatively low estimated activation energy for both processes, peroxymonosulfate decomposition and phenol degradation. The estimated activation energy values are about 30 and 32 kJ mol−1. The stability of the most active catalyst was assessed by performing eight consecutive uses without observing decrease of catalytic activity, neither metal leaching or metal nanoparticle aggregation. Turnover numbers/turnover frequencies values as high as 4·105/8·105 h−1 for peroxymonosulfate activation and 39·103/68·103 h−1 for phenol degradation at pH 7 and 20 °C have been estimated, respectively. Electron paramagnetic resonance measurements and selective quenching experiments revealed that the generated sulfate radicals from peroxymonosulfate rapidly are transformed in highly reactive hydroxyl radicals. In excellent agreement with previous reports, this work demonstrates the importance of an adequate activated carbon functionalization to obtain superior and stable catalysts for peroxymonosulfate activation.Graphical abstractGraphical abstract for this article
       
  • Aerobic oxidative coupling of amines to imines by mesoporous copper
           aluminum mixed metal oxides via generation of Reactive Oxygen Species
           (ROS)
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Deepamali Dissanayake, Laura A. Achola, Peter Kerns, Dinithi Rathnayake, Junkai He, John Macharia, Steven L. Suib A mesoporous, monomodal copper aluminum mixed metal oxide (MMO) (average pore size 9.63 nm, surface area 140 m2/g) synthesized via a modified inverse micelle method, efficiently catalyzes aerobic oxidative coupling of amines to imines. This material exhibits excellent conversion (>99%) and selectivity (>99%) towards imine synthesis under mild, solvent free, green conditions utilizing atmospheric air as the sole oxidant. Catalytic activity is observed for a diverse range of amine substrates. The aerobic oxidation of amines to imines follows a unique mechanistic pathway which involves Reactive Oxygen Species (ROS).Graphical abstractGraphical abstract for this article
       
  • Heterostructured simple perovskite nanorod-decorated double perovskite
           cathode for solid oxide fuel cells: Highly catalytic activity, stability
           and CO2-durability for oxygen reduction reaction
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Feifei Lu, Tian Xia, Qiang Li, Jingping Wang, Lihua Huo, Hui Zhao Apart from conventional composite materials, in situ exsolution for constructing the heterostructure is one of the most effective strategies to design the high-performance electro-catalysts. Herein we report a novel heterostructured simple perovskite nanorod-decorated A site-deficient double perovskite PrBa0.94Co2O5+δ (SPN-A-PBC) cathode, synthesized by an in situ exsolving process from A site-deficient double perovskite PrBa0.94Co2O5+δ (A-PBC). The results demonstrate a highly electro-catalytic activity of the SPN-A-PBC cathode toward oxygen reduction reaction (ORR) for intermediate-temperature solid oxide fuel cells (IT-SOFCs), achieving a very low and stable polarization resistance of ˜0.025 Ω cm2 at 700 °C in air. The anode-supported single cell with this heterostructured cathode delivers a maximum power density of 1.1 W cm−2 at 700 °C and a superior steady operation over 120 h at a loading voltage of 0.6 V. Furthermore, the SPN-A-PBC electrode exhibits a good tolerance to CO2. When tested in air with 6 vol% CO2 at 700 °C, the SPN-A-PBC electrode still maintains a stable polarization resistance of ˜0.078 Ω cm2. The unique catalytic activity of the SPN-A-PBC cathode for ORR may be attributed to extended active sites, abundant interface defects, enhanced redox property and oxygen mobility. The fast ORR kinetics and excellent durability in air with CO2 highlight the potential of SPN-A-PBC as a potential functional material in the energy conversion devices.Graphical abstractGraphical abstract for this article
       
  • Comparative studies of P/CeO2 and Ru/CeO2 catalysts for catalytic
           combustion of dichloromethane: From effects of H2O to distribution of
           chlorinated by-products
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Qiguang Dai, Jinyan Wu, Wei Deng, Jiasu Hu, Qingqing Wu, Limin Guo, Wei Sun, Wangcheng Zhan, Xingyi Wang Phosphate- and ruthenium oxide-supported CeO2 (P/CeO2 and Ru/CeO2), as typical CeO2-based catalysts, were comparatively studied to fully elucidate catalytic combustion of dichloromethane (DCM), especially for the effects of H2O and the formation of chlorinated by-products. The results indicated that the reversible inhibitive effect of H2O became increasingly intense in the following order: pristine CeO2 < Ru/CeO2 < P/CeO2, moreover, the inhibition was more notable at the lower reaction temperature but almost disappeared at temperatures above 300 °C. H2O-TPD and various DRIFTS techniques revealed that the adsorption strength of H2O depended on the surface properties of three CeO2-based catalysts and the reaction temperature, which eventually determined the degree of activity inhibition. Dechlorinated (monochloromethane, MCM) and ploychlorinated (CHCl3 and CCl4) by-products were more easily formed over non-metallic P/CeO2 and metallic Ru/CeO2, respectively, due to the different redox and metallic properties of these CeO2-based catalysts, which was also further confirmed by catalytic oxidation of other chlorinated volatile organic compounds (Cl-VOCs). Additionally, more complete oxidation (the formation of CO2 and Cl2) occurred on Ru/CeO2.Graphical abstractGraphical abstract for this article
       
  • One-step construction of Pickering emulsion via commercial TiO2
           nanoparticles for photocatalytic dye degradation
    • Abstract: Publication date: 15 July 2019Source: Applied Catalysis B: Environmental, Volume 249Author(s): Qin Li, Tingting Zhao, Mei Li, Wenting Li, Bin Yang, Dongran Qin, Kangle Lv, Xian Wang, Lamei Wu, Xiaofeng Wu, Jie Sun Pickering emulsion (PE) stabilized by semiconductors for photocatalysis applications has received growing endorsement over the last decade due to its high interfacial activity. However, since most semiconductors inherently possess a strongly hydrophilic or hydrophobic surface and are unable to stabilize PE microcapsules by themselves, pretreating the surface of semiconductor powder with foreign modifier was usually unavoidable and inconvenient before the PE construction. Even worse, the added modifier inevitably limited the contact between the semiconductor and the reactant during the photocatalysis process. Herein, an oil-in-water PE was successfully obtained in one step without pretratment of the semiconductor, where the dye-contained wastewater and insoluble organic matter acted as the water and oil phases, respectively, and the dye molecules in water could directly assist TiO2 particles to become the stabilizer. The TiO2 powder in the formed PE system exhibited markedly enhanced photoactivity for dye degradation over that in traditional non-emulsified systems, and the PE microcapsules could be easily recovered for reuse and withstand long-term irradiation without severe demulsification. This work not only highlights a convenient and promising approach to build Pickering emulsion as a novel photocatalytic system with extremely high efficiency and recyclability, but also provides a new way of thinking on how to simplify the PE construction to meet more requirement in future practical applications.Graphical abstractPickering emulsions were stabilized by commercial TiO2 nanoparticles in one step, and exhibited excellent efficiency and recyclability for photocatalytic dye degradation.Graphical abstract for this article
       
  • Selective oxidation of cyclohexane to cyclohexanol by BiOI under visible
           light: role of the ratio (1 1 0)/(0 0 1) facet
    • Abstract: Publication date: Available online 21 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): David Contreras, Victoria Melin, Katherine Márquez, Gabriel Pérez-González, Héctor D. Mansilla, Gina Pecchi, Adolfo Henríquez The development of semiconductors capable of photocatalytic activity under visible light is very important, because such materials are potentially useful for performing photocatalytic conversion under solar illumination. However, these processes are frequently unselective because they involve the production of free radicals. Reports suggest that the selectivity of the photocatalytic processes may be adjusted through modification of the structural parameters of the semiconductor photocatalysts by the preferential exposure of certain crystalline planes.The present work focuses on the relationship between the preferential exposure of the (1 1 0) and (0 0 1) facets of bismuth oxyiodide and the cyclohexanol produced by the photocatalytic oxofunctionalization of cyclohexane. For this purpose, four bismuth oxyiodide photocatalysts (BiOI-4, BiOI-6, BiOI-10, and BiOI-12) were synthesized at different pH levels and characterized (via X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, and the Brunauer–Emmett–Teller surface area). All BiOI photocatalysts showed higher selectivity for cyclohexanol. Additionally, a linear dependence between the cyclohexanol yield and peak intensity (1 1 0)/(0 0 1) ratio was established and related to the relative amount of hydroxyl radicals formed in the photocatalytic system.Graphical abstractGraphical abstract for this article
       
  • Photocatalytic oxidation of MEK over hierarchical TiO2 catalysts: Effect
           of photocatalyst features and operating conditions
    • Abstract: Publication date: Available online 21 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Alireza Haghighat Mamaghani, Haghighat Fariborz, Lee Chang-Seo A novel hydrothermal route was developed to synthesize crystalline and hierarchically porous TiO2 at mild conditions under acidic/basic reaction environments. A good control over the key features of catalysts could be achieved by varying the pH of the starting solution (pH = 2-12) and type of acid during preparation. Crystalline, textural, and optical properties of photocatalysts were characterized in order to explore the connections between catalysts’ features and photoactivity. The activities of catalysts were evaluated for decomposition of methyl ethyl ketone (MEK) in a continuous flow photoreactor. To gain insight into the impact of main operating conditions on photocatalytic oxidation (PCO) processes, experiments were conducted at wide ranges of inlet concentration, relative humidity, and residence time. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that yielded titania samples possess good crystallinity and mainly consist of anatase polymorph. Results of X-ray photoelectron spectroscopy (XPS) indicated that the population of hydroxyl groups on the surface of TiO2 declines as the acidity of hydrothermal solution increases. Hierarchical porous structure with ultra-long parallel macrochannels and large macropores (> 0.5 µm) could be directly observed in scanning electron microscopy (SEM). The multimodal porous structure offers higher light utilization, enhanced mass transport, and superior adsorption capacity for air pollutants. Photoluminescence spectroscopy revealed that the enhancement in crystallinity has an impact on the separation of photo-induced charge carriers. Moreover, a satisfactory linear correlation between the ability of photocatalysts to generate •OH and crystallinity could be found. Under the harshest operating condition (residence time = 0.012 s, relative humidity = 50%, concentration = 1000 ppb), the TiO2 synthesized in nitric acid (pH = 4) achieved the highest MEK removal efficiency, 36.9%, which substantially surpassed that of P25, 14.5%. Hierarchical porosity, optimum trade-off between surface area and crystallinity, existence of meso- and macropores, small crystal size, and high •OH generation ability could account for the superior performance. A tentative reaction pathway for MEK photodegradation and a health-risk index were put forward considering the by-products detected in the gas phase.Graphical abstractGraphical abstract for this article
       
  • BN/GdxTi(1-x)O(4-x)/2 nanofibers for enhanced photocatalytic hydrogen
           production under visible light
    • Abstract: Publication date: Available online 21 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Amr A. Nada, Maged F. Bekheet, Roman Viter, Philippe Miele, Stéphanie Roualdes, Mikhael Bechelany BN/GdxTi(1-x)O(4-x)/2 nanofibers were elaborated via electrospinning technique. The properties of the prepared nanofibers were controlled using different ratios of gadolinium. All the prepared nanofibers exhibit the tetragonal structure of anatase TiO2 phase. An increase in the unit cell volume and a decrease in the crystallite size were observed with increasing the doping amount of Gd3+ as revealed by Rietveld refinement analysis. The defect in TiO2 lattice was observed by Raman. The Gd3+ incorporation inside TiO2 lattice, which is accompanied by the creation of Ti-O-Gd bond, was characterized by the X-ray photoelectron spectra. Scanning electron microscopy demonstrates that the average diameter of BN/GdxTi(1-x)O(4-x)/2 nanofibers decreased by 0.1 µm in comparison to nanofibers without doping. The d-spacing raised by 0.01 nm after doping as demonstrated by high-resolution transmission electron microscopy. The distribution of BN and Gd3+ was homogenous and uniform on nanofibers as depicted by EDX. The incorporation of many impurity levels between valence band and conduction band enhanced absorptivity under visible light as revealed by UV − visible spectrophotometry. Moreover, the surface area of nanofibers was improved by 5 times after Gd3+ doping as demonstrated by BET which is favorable for the increase of photocatalytic activity. The electrons transfer rate (recorded by the electrochemical impedance spectroscopy analysis) was improved by gadolinium doping as well. The photocatalytic results indicate that the BN/GdxTi(1-x)O(4-x)/2 nanofibers improve hydrogen production up to 192602 ± 1500 µmole/g during 6 hours under visible light. The BN/GdxTi(1-x)O(4-x)/2 nanofibers produced 7 times more hydrogen than nanofibers without BN. This improvement could be attributed to the e-/h+ stability that reached 63.69 ms average time before recombination due to the beneficial effect of BN nanosheets.Graphical abstractGraphical abstract for this articleElaborated of BN/GdxTi(1-x)O(4-x)/2 nanofibers which has oxygen vacancies and impurity levels of gadolinium. which enhanced the hydrogen production by water splitting under visible light and it has highly stability between electrons and holes.
       
  • Influence of yolk-shell Au@TiO2 structure induced photocatalytic activity
           towards gaseous pollutant degradation under visible light
    • Abstract: Publication date: Available online 21 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Yunyang Wang, Changzhu Yang, Ayan Chen, Wenhong Pu, Jianyu Gong Core-shell and yolk-shell Au@TiO2 NPs were successfully synthesized, and the morphology differences were observed. Its photocatalytic activity was evaluated by photocatalytic oxidation of gaseous toluene under visible light illumination. The results indicated that yolk-shell Au@TiO2 exhibited superior photocatalytic properties and demonstrated a good stability. Almost 57.3% of gaseous toluene was removed over 0.14 at% yolk-shell Au@TiO2 in 3 h. It could also be reused for several times without corrosion. Furthermore, the comprehensive effect of LSPR response of Au, high cavity volume of yolk-shell structure, larger specific surface area, more mesoporous and the existence of Ti3+ were all benefit for the photocatalytic process. ESR tests also confirmed that h+, •OH, •O2- and Ti3+ generated from yolk-shell Au@TiO2 were the main active species in the photocatalytic degradation progress of gaseous toluene under visible light irradiation.Graphical abstractGraphical abstract for this article
       
  • Nitrogen treatment generates tunable nanohybridization of Ni5P4 nanosheets
           with nickel hydr(oxy)oxides for efficient hydrogen production in alkaline,
           seawater and acidic media
    • Abstract: Publication date: Available online 20 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Yongchao Huang, Lei Hu, Ran Liu, Yuwen Hu, Tuzhi Xiong, Weitao Qiu, M.-Sadeeq (Jie Tang) Balogun, Anlian Pan, Yexiang Tong Hybrid engineering of electrocatalysts is still very challenging for electrochemical water splitting. Ni5P4 is a promising electrocatalyst for hydrogen evolution reaction (HER) but the formation of phosphide-hydrogen on Ni5P4 (P-Hads) bonds usually weakens the HER activity. Herein, we report a simple nitrogen treatment strategy to controllably hybridize Ni5P4 porous nanosheets with amorphous nickel hydr(oxy)oxide [Ni2+δOδ(OH)2-δ] layer and utilize as efficient electrocatalyst for hydrogen evolution reaction (HER) in neutral (real seawater), alkaline and acidic media. The in-situ derived Ni5P4@Ni2+δOδ(OH)2-δ hybrid nanosheets can be obtained by annealing the nickel hydroxide-precursor nanosheets coupled with decomposition of NaH2PO2·H2O in nitrogen atmosphere. Benefiting from the thin amorphous Ni2+δOδ(OH)2-δ coated layer, the optimized Ni5P4@Ni2+δOδ(OH)2-δ with 3 nm amorphous layer achieve a current density of 10 mA cm−2 at low overpotential of 87, 144 and 66 mV in alkaline, seawater and acidic media, respectively. Theoretical and experimental analyses show that the hybridization of Ni5P4 and Ni2+δOδ(OH)2-δ could not only serve as protection to further enhance the electrocatalytic properties and high surface area of the hybrid electrocatalyst but also create good electronic interaction and synergistic properties for suppressing P-Hads bonds, which is beneficial for promoting water adsorption and optimizing the free energy of hydrogen adsorption for triggering the catalytic pathway at all pH range. This work offers new insights for facile designing of non-precious transition metal compound hybrids for HER with enhancing electrocatalytic performance and opens a promising pathway for hydrogen production at all-pH range.Graphical abstractGraphical abstract for this article
       
  • Photocatalytic Hydrogen Evolution on P-type Tetragonal Zircon
           BiVO4
    • Abstract: Publication date: Available online 20 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Junpeng Wang, Yanan Song, Jing Hu, Yu Li, Zeyan Wang, Ping Yang, Gang Wang, Qian Ma, Quande Che, Ying Dai, Baibiao Huang Tetragonal zircon BiVO4 (P-BiVO4) were grown on fluorine-doped tin oxide (FTO) glass via hydrothermal method. The cathodic photocurrent and Mott-Schottky analysis indicate that the tetragonal zircon BiVO4 is a p-type semiconductor. Inductively coupled plasma (ICP) analysis and X-ray photoelectron spectrum showed that there are Bi vacancies and interstitial oxygen exist in the crystal, which are the origin of the p-type conductivity. The flat band potential of the P-BiVO4 is about 1.33 V (vs Ag/AgCl) inferred from Mott-Schottky plots. Combining with diffuse reflection spectrum and valence band X-ray photoelectron spectrum, the calculated conduction band value of the P-BiVO4 is about 0.06 V vs RHE, slightly higher than the reduction potential of hydrogen. However, the P-BiVO4 exhibit hydrogen production activity under Xe light irradiation even though its conduction band level is not negative enough. This can be attributed to the hot carrier processes in p-type semiconductors.Graphical abstractGraphical abstract for this article
       
  • Carbon Nanotubes with Rich Pyridinic Nitrogen for Gas Phase CO2
           Electroreduction
    • Abstract: Publication date: Available online 20 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Chen Ma, Pengfei Hou, Xiuping Wang, Zhuo Wang, Wenting Li, Peng Kang Nitrogen doped carbon nanotubes (NCNTs) with high concentration of pyridinic N sites (62.3% of all nitrogen) were prepared by pyrolysis of phenathroline heterocycle precursor, and they can reduce CO2 to CO with high selectivity and stability. Faradaic efficiency of CO maintained>94.5% between −0.6 to −0.9 V vs the reversible hydrogen electrode (RHE), and the CO current density was as high as 20.2 mA•cm−2. Moreover, during 40 hours electrolysis at −0.8 V Faradic efficiency for CO was stable at 95%. The high performance came from rich concentrations of pyridine N sites in NCNTs, serving as the active sites for catalysis. Furthermore, gas phase CO2 electrolysis showed nearly 100% Faradic efficiency for CO, suggesting that the NCNT can maximize the CO2 reduction efficiency and the hydrogen evolution was suppressed completely.Graphical abstractCarbon nanotubes with high pyridinic nitrogen content exhibited high efficiency and selectivity for CO2 reduction reaction. They were used in gas phase CO2 electrolysis and achieved nearly 100% efficiency for CO.Graphical abstract for this article
       
  • Highly efficient visible-light-driven photocatalytic degradation of VOCs
           by CO2-assisted synthesized mesoporous carbon confined mixed-phase TiO2
           nanocomposites derived from MOFs
    • Abstract: Publication date: Available online 20 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Hongli Liu, Yaping Ma, Jiangyao Chen, Meicheng Wen, Guiying Li, Taicheng AnABSTRACTImproving the visible light response and efficient separation of electron-hole pairs play vital roles in commonly used TiO2 photocatalyst for VOCs degradation. Herein, N-doped mesoporous carbon encapsulated anatase-rutile phase junction TiO2 (TiO2@C-N(x)) was successfully synthesized via the pyrolysis of a representative amine functionalized Ti-based MOF, NH2-MIL-125, under the atmosphere of Ar and subsequent CO2 treatment. Our synthesis stragety was based on the rational regulation of the formation of TiO2 phase junction and the decomposition of amorphous carbon onto the TiO2@C-N (without subsequent CO2 process) using CO2 as both anatase-rutile phase transformation promoter and mild oxidant. Compared with TiO2@C-N, TiO2@C-N(x) nanocomposites with subsequent CO2 process exhibit significantly improved photocatalytic activity as well as mineralization efficiencies. For example, the mineralization efficiency reached 51.9% at 62.4% of styrene degradation within 240 min of visible-light irradiation by using the optimal TiO2@C-N(30) nanocomposites as compared with only 19.7% mineralization efficiency at 31.0% of styrene degradation under the same conditions of TiO2@C-N. Furthermore, the primary radicals involved in degradation of VOCs was identified by electron paramagnetic resonance spectroscopy, and the possible degradation intermediates were also monitored by means of proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Finally, the radicals involved degradation reaction mechanism was also tentatively proposed.Graphical abstractN-doped mesoporous carbon confined TiO2 nanocomposites with controllable TiO2 phase junction with strong interface interaction were synthesized for the first time via the pyrolysis of NH2-MIL-125 using CO2 as both phase transformation agent and mild oxidant. The resulting TiO2@C-N(x) nanocomposites exhibited higher degradation and mineralization effciencies as compared with TiO2@C-N in the photocatalytic degradation of gaseous styrene under vsisble light irradation.Graphical abstract for this article
       
  • Enhanced photocatalytic ozonation of organic pollutants using an
           iron-based metal-organic framework
    • Abstract: Publication date: Available online 20 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Deyou Yu, Lubiao Li, Minghua Wu, John C. Crittenden The photocatalytic activity of metal-organic frameworks (MOFs) is drawing great attention in the field of environmental remediation. However, the efficiency of MOFs still remains low because of the rapid recombination of valence band holes and conduction band electrons (a.k.a., charge carriers). The combination of photocatalysis and electron acceptors such as ozone are believed to be an efficient strategy to reduce the charge carrier recombination. Herein, we report that photocatalytic ozonation (PCO) using an Fe-based MOF (MIL-88A(Fe)) has greater destruction than photocatalysis and/or catalytic ozonation in terms of 4-nitrophenol (4-NP) degradation and mineralization. It is worth noting that our Fe-based MOF has a large number of Lewis acid sites (LAS). The pseudo-first order kinetic rate constants (k) of 4-NP degradation using PCO, photocatalysis and catalytic ozonation systems are 0.1632, 0.0143 and 0.0840 min-1, respectively. The TOC removal of 4-NP in the PCO system is approximately 75.4% ([4-NP]=100 ppm, ozone input dosage=1.5 mg/min-L, UV light intensity=3.46×10-6 Einstiens/L-s, treatment time=30 min) and this is much greater than those of photocatalysis (17.6%) and catalytic ozonation (38.7%). Most importantly, both the k value and TOC removal in the PCO system are much higher than the sum of those in other two processes, implying a strong synergistic effect in the PCO process. Mechanistic studies were conducted using electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) measurements and demonstrate that the synergistic effect may originate from the enhanced photoinduced carrier separation using ozone as an electron acceptor. Furthermore, ·OH, ·O2-, and 1O2 are found to be the principal reactive oxygen species (ROS) for 4-NP degradation and mineralization. Integrating the analysis of band structure, EPR and scavenging experiment results, ozone is not only able to reduce charge carrier recombination but also can be catalytically decomposed to generate more ROS on the LAS of MIL-88A(Fe). This study provides deep insights into the use of MOFs as effective advanced oxidation processes (AOPs).Graphical abstractGraphical abstract for this article
       
  • In-situ pyrolysis of Enteromorpha as carbocatalyst for catalytic removal
           of organic contaminants: considering the intrinsic N/Fe in Enteromorpha
           and non-radical reaction
    • Abstract: Publication date: Available online 20 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Cheng Chen, Tengfei Ma, Yanan Shang, Baoyu Gao, Bo Jin, Hongbing Dan, Qian Li, Qinyan Yue, Yanwei Li, Yu Wang, Xing Xu An environmentally friendly, facile, and economical Fe/N co-doped carbonaceous material (Fe-N@C) was prepared by the in-situ pyrolysis of Fe/N rich Enteromorpha biomass for peroxymonosulfate activation and organic contaminants degradation. Results indicated that Enteromorpha-based catalysts prepared at high pyrolysis temperature displayed some highly graphitic nanosheets with rich nitrogen doped. The graphitic N derived from the intrinsic N in Enteromorpha showed the high correlation with the paracetamol (PCM) removal rate; this was confirmed by the Density Functional Theory (DFT) calculation, showing the high adsorption energy (ΔEads, -2.62 eV) of PMS molecular adsorbed onto the graphitic N area. A weak correlation between the PCM removal rate and adsorption capacity was also observed, revealing that the PCM catalytic reaction could be greatly accelerated after the pre-adsorption. It was interesting that the intrinsic Fe in Enteromorpha did not affect the PCM degradation, but PCM removal rate of acid treated Fe-N/C was improved as more active sites were formed after the Fe extraction by acid treatment. Both the radical pathways of O2·- and non-radical 1O2 generated in the Fe-N@C/PMS system were the primary mechanisms for the PCM degradation, which was consistent with the Fukui function values of f° and f- based on the DFT calculation. In addition, high stability of the carbon-based catalysts was observed after three runs and calcinating regeneration, which showed the promising applications for environmental remediation.Graphical abstractGraphical abstract for this article
       
  • Fabrication of Bi2MoO6/ZnO hierarchical heterostructures with enhanced
           visible-light photocatalytic activity
    • Abstract: Publication date: Available online 19 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Guping Zhang, Dongyun Chen, Najun Li, Qingfeng Xu, Hua Li, Jinghui He, Jianmei Lu The construction of heterostructures is regarded as an excellent strategy to achieve efficient charge separation and improved photocatalytic activity. Herein, a series of Bi2MoO6/ZnO hierarchical heterostructured photocatalysts were synthesized by a solvothermal method. The morphology of Bi2MoO6 grown on the surface of ZnO nanorods could be controlled by adjusting the experimental conditions. The synthesized samples were characterized by various analytical techniques and their photocatalytic performance was evaluated by photocatalytic reduction of Cr(VI) under visible-light irradiation. Compared with those of pure Bi2MoO6 and ZnO, the Bi2MoO6/ZnO composites showed higher photocatalytic activity towards the reduction of Cr(VI). The enhanced photocatalytic activity was mainly attributed to the formation of a heterojunction between Bi2MoO6 and ZnO, which effectively facilitated the separation and transfer of electrons and holes. In addition, the Bi2MoO6/ZnO photocatalysts maintained good stability after three cycles of Cr(VI) photoreduction. A possible photocatalytic mechanism of the as-synthesized composites was proposed.Graphical abstractGraphical abstract for this articleThe 3D Bi2MoO6/ZnO hierarchical heterostructures are fabricated via solvothermal methods with enhanced photocatalytic activity, for efficient photocatalytic reduction of Cr(VI).
       
  • Selective Oxidation of Alkylarenes to Aromatic Acids/Ketone in Water by
           Using Reusable Binaphthyl Stabilized Pt Nanoparticles (Pt-BNP) as Catalyst
           
    • Abstract: Publication date: Available online 19 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Rajib Saha, Govindasamy Sekar sAn efficient methodology for the selective and controlled oxidation of petroleum waste methylarenes/alkylarenes to aromatic carboxylic acids/ketone using easily recoverable and recyclable binaphthyl stabilized Pt nanoparticles (Pt-BNP) as a catalyst has been developed. The greener oxidant aq. tert-butyl hydroperoxide (TBHP) and green solvent water have been utilized in this oxidation reaction. The methodology is well tolerated with different functional groups. The less reactive electron deficient toluenes are also oxidized by Pt-BNP and gave a good yield of corresponding carboxylic acids with a high turnover number (TON) 738-1448. The Pt-BNP catalyst was recovered and reused up to five catalytic cycles. The heterogeneous test suggested that the reaction is catalyzed by heterogeneous Pt-BNP catalysts. Based on control experiments and literature reports, a possible reaction mechanism has been proposed.Graphical Graphical abstract for this article
       
  • Influence of Na, P and (Na+P) poisoning on a model copper-ferrierite
           NH3-SCR catalyst
    • Abstract: Publication date: Available online 18 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Marie-Laure Tarot, Eduard Emil Iojoiu, Vincent Lauga, Daniel Duprez, Xavier Courtois, Fabien Can To highlight the deactivation mechanisms encountered by minerals impurities from biodiesel, the effects caused by Na, P or (Na + P) additions were studied over a model Cu-FER catalyst. Na, P or (Na + P) were added by wet-impregnation in water in a wide concentration range up to 2 wt-%. The catalytic behaviors were evaluated by NH3/NO oxidation and standard/fast NH3-SCR reactions. In addition, a combination of several characterization techniques (ICP–AES, N2 adsorption/desorption, XRD, NH3-TPD, NO adsorption monitored by FTIR and H2-TPR) was applied to provide useful information regarding the deactivation mechanism caused by the minerals addition. Sodium and phosphorus interacted differently with the Cu-FER catalyst. Na addition induced a loss of Brønsted acid sites and a back-exchange of Cu2+ with Na+, with formation of external CuO species, thus favoring the oxidation of NO and NH3. After phosphorus addition, the exchanged Cu2+ species remained moderately affected, but direct interactions with copper were evidenced which were primarily responsible for catalyst deactivation toward the oxidation reactions. After equimolar addition of phosphorus and sodium, both Na and P effects were observed. For the NH3-SCR process, the ammonia adsorption ability, which depends on both acidity and copper units, appeared the main key parameter driving the catalytic activity at low temperature (T ≤ 250 °C). Phosphorus appeared to be the major responsible for catalyst deactivation after (Na + P) co-poisoning.Graphical abstractGraphical abstract for this article
       
  • Cobalt Phthalocyanine Coordinated to Pyridine-Functionalized Carbon
           Nanotubes with Enhanced CO2 Electroreduction
    • Abstract: Publication date: Available online 18 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Minghui Zhu, Jiacheng Chen, Rong Guo, Jing Xu, Xiangchen Fang, Yi-Fan Han Electrochemical reduction of CO2 is promising to utilize the intermittent renewable electricity and transform CO2 into value-added products, simultaneously. Herein, we designed a cobalt phthalocyanine-based catalyst supported on pyridine-functionalized carbon nanotubes (CoPc-py-CNT). This novel hybrid catalyst exhibited a high activity (TOFCO: 34.5 s-1 at -0.63 V vs. RHE) and selectivity (FECO> 98%) for electrochemical CO2 reduction. To the best of our knowledge, it is the best one among all reported molecular based electrocatalysts for CO2-to-CO conversion. Furthermore, structure characterizations (such as Raman and X-rays photoelectron spectroscopy), loading-dependent electrochemical analysis and mechanistic studies revealed that pyridine groups, through axial coordination with Co, not only functioned as physical promoters to improve the dispersion of cobalt phthalocyanine but also tuned the electronic structure of Co sites to increase the intrinsic turnover frequency.Graphical abstractGraphical abstract for this article
       
  • A Facile Strategy Of Enhancing Interaction Between Cerium And Manganese
           Oxides For Catalytic Removal Of Gaseous Organic Contaminants
    • Abstract: Publication date: Available online 18 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Jin Chen, Xi Chen, Dongxu Yan, Mingzhu Jiang, Wenjian Xu, Hao Yu, Hongpeng Jia A facile strategy of redox etching-precipitation is developed to support cerium oxide (CeOy) on crystal α-type manganese dioxide nanorod (OMS). By means of this method, the contact between CeOy and OMS can be strengthened and results in enhancement of interfacial effect, thereby causing consequent changes in physicochemical properties. Through screening and evaluation, the as-prepared catalyst of 5.0% CeOy/OMS (5.0% Ce/OMS) with an optimal Ce/Mn molar ratio of 0.05, owning more acidity, more surficial oxygen vacancy as well as more mobility of lattice oxygen, exhibits a remarkable activity and stability for catalytic oxidation of chlorobenzene. Under catalysis of 5.0% Ce/OMS, the demanded temperature for complete removal of chlorobenzene is about 360 °C, which is lower than the required temperature (above 400 °C) for NH3-5.0% Ce/OMS prepared via conventional method of NH3⋅H2O precipitation. Meanwhile, 5.0% Ce/OMS shows a good tolerance to high water content (10 vol.%) and a better recyclability, adapts to oxidation of various kinds of volatile organic compounds (VOCs) and VOCs mixture under simulated realistic exhaust condition. With correlation of structure and performance, it is revealed that interface acts as active site to catalyze oxidation.Graphical abstractGraphical abstract for this article
       
  • Visible light assisted thermocatalytic reaction of CO + NO over
           Pd/LaFeO3
    • Abstract: Publication date: Available online 18 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Gang Cheng, Xiaofang Tan, Xinjie Song, Xun Chen, Wenxin Dai, Rusheng Yuan, Xianzhi Fu A LaFeO3 supported Pd nanoparticle catalyst Pd/LaFeO3 was prepared by a two-step precipitation-deposition method. Its catalytic performance for the reduction of NO by CO was subsequently evaluated in the lower temperature under visible light irradiation or not. It was found that visible light could boost the progress of the reaction and the selectivity of forming N2. The results of temperature-programmed desorption (TPD) of CO and in-situ diffuse reflectance infrared Fourier transform spectra (in-situ DRIFTS) showed that visible light could enhance the adsorption of NO and its activation at Pd or LaFeO3 site and that of CO at Pd site, respectively. Co-adsorption results of NO + CO suggested that the activated intermediates of CO and NO would further interact to form the isocyanate (-NCO) and N2O species, which finally transformed to N2 and CO2. Based on the results of Raman spectrum, H2-temperature programmed reduction (TPR), the X-ray photoelectron spectroscopy (XPS), photoluminescence spectra (PL) and photocurrent testing, it was proposed that visible light irradiation could cause the increase in surface electron density of Pd nanoparticles by the photo-induced electron (from O2p to Fe3d orbit) transfer from LaFeO3 to Pd. Moreover, the valence exchange of Fe4+ and Fe3+ induced by visible light could promote the formation of oxygen vacancies and then the adsorption and activation of CO and NO. This result also indicated that the photo-excitation of supports could strengthen the strong interaction between support and metal nanoparticles, and then promote the thermo-catalytic reactivity of catalysts.Graphical abstractGraphical abstract for this article
       
  • Facile synthesis of bimetallic Pt-Pd symmetry-broken concave nanocubes and
           their enhanced activity toward oxygen reduction reaction
    • Abstract: Publication date: Available online 18 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Rifeng Wu, Panagiotis Tsiakaras, Pei Kang Shen In the present work, we are reporting a facile one-pot synthesis route to get Pt-Pd symmetry-broken concave nanocube (SBCNCs) structures in N, N-dimethylformamide (DMF) solutions under the effect of iodide ions and Poly (vinylpyrrolidone) (PVP). By given the inhibiting effect of non-stirring during the reaction process, and the capping agent effect, newly formed atoms is expected to accumulate at the vertexes and/or the edges of nanocube, leading to the formation the Pt-Pd SBCNCs. These structures are in a thorough manner physicochemically and electrochemically characterized.It is found that the specific structure of Pt-Pd SBCNCs is composed of various high-index facets and Pt-rich surface. These features enable a superior performance for the oxygen reduction reaction, and the specific/mass activities of the Pt-Pd SBCNCs are 7.7/6.2 times higher than commercial TKK-Pt/C, respectively. It also exhibits a remarkable durability by only reduced 30 mV half-wave potential after 15,000 accelerated durability test (ADT) cycles. This work provides an effective and simple strategy to rationally design electrocatalysts with enhanced activity and durability toward oxygen reduction reaction or other practical applications.Graphical abstractGraphical abstract for this article
       
  • Enhanced electrocatalytic activity of Pd and Pd-polyaniline nanoparticles
           on electrochemically exfoliated graphite sheets
    • Abstract: Publication date: Available online 16 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): R. Venkata Jagadeesh, V. Lakshminarayanan The catalyst support materials play an important role in improving the performance of electrocatalysts for alcohol oxidation reaction. In this work, flexible graphite sheets containing a large number of edge planes were electrochemically exfoliated by the application of large positive and negative potentials in acetonitrile medium. The process described here produces several surface functional groups on graphite sheet surface. In this work, the utility of such a functionalized surface is explored as a solid support for depositing Pd and Pd-PANI nanostructures which are studied for oxidation of alcohols in alkaline medium. The results show that these electrode materials exhibit an excellent electrocatalytic activity with very high turnover frequency and low activation energy values for ethanol oxidation reaction that has the potential to be used in low temperature polymer membrane alkaline fuel cells.Graphical abstractGraphical abstract for this article
       
  • Engineering a cobalt clathrochelate/glassy carbon interface for the
           hydrogen evolution reaction
    • Abstract: Publication date: Available online 16 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Joumada Al Cheikh, Angel Villagra, Alireza Ranjbari, Alexandre Pradon, Manuel Antuch, Diana Dragoe, Pierre Millet, Loïc Assaud The purpose of this work was to investigate the electrocatalytic activity of a molecular clathrochelate, containing cobalt as active centre, for the hydrogen evolution reaction (HER) in aqueous acidic media. The electrocatalytic activity of this cobalt complex has been measured using a glassy carbon working electrode, with the complex either dissolved in the electrolyte (homogeneous phase) or electro-grafted at the surface (heterogeneous phase). The complex was electrografted via diazonium derivatives reduction, in an attempt to form a surface monolayer of cobalt clathrochelate, covalently bonded to the glassy carbon substrate. The chemical composition and morphology of the modified electrode have been characterized by electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The HER kinetics on the two electrodes has been analyzed by cyclic voltammetry and electrochemical impedance spectroscopy in two different media: in acetonitrile (by adding increasing amounts of equivalent protons) and in 0.1 M H2SO4 aqueous solution. Tafel slopes and exchange current density values have been determined on both electrodes, in both media, and compared. It was found that the onset of the HER requires a significantly lower overpotential (≈ 800 mV less) when the complex is electrografted at the surface of the working electrode. The hydrogen production rate, determined by gas chromatography, is reported.Graphical Graphical abstract for this article
       
  • Synergetic Effect in RuxMo(1-x)S2/SBA-15 Hydrodesulfurization Catalysts:
           Comparative Experimental and DFT Studies
    • Abstract: Publication date: Available online 14 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): T.A. Zepeda, N.L. Torres-García, J. Antúnez-García, D.H. Galván, B. Pawelec, R. Huirache-Acuña, J.N. Díaz de León, G. Alonso-Núñez, J.L.G. Fierro, S. Fuentes The effect of introducing Ru impurities into the MoS2 crystalline structure of the sulfided RuxMo(1-x)S2/SBA-15 catalysts have been investigated using density functional theory (DFT) calculations and the catalyst characterization by different techniques (chemical analysis (ICP-AES), temperature-programmed reduction (TPR), X-ray diffraction (XRD), N2 physisorption, DRIFTS of adsorbed pyridine (DRIFTS-Py) and X-ray photoelectron spectroscopy (XPS)). The catalyst activity was tested in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) reaction carried out in a batch reactor, T = 320 °C and total H2 pressure of 5.5 MPa. From electronic structure DFT calculations is was concluded that the 4d orbitals of both Mo and Ru played an important role in the catalyst optimization being the processes of transport and charge transference the most important ones. It was found that the enrichment with Ru, promotes a greater electronic participation (DOS at the Fermi level) of the different atoms in the RuxMo(1-x)S2 phase leading to metallization of the Mo ions. The catalyst activity in HDS of DBT reaction demonstrated a similar behavior to that of theoretical density of states (DOS) calculated via DFT. All bimetallic systems presented the synergetic effect between Ru and Mo in the HDS of DBT reaction over RuxMo(1-x)S2/SBA-15 catalysts. The highest activity observed for Ru content of x = 0.4 was consistent with theoretical results predicting that the optimum DOS contributions should be around x = 0.44. The most active Ru0.4Mo0.6S2/SBA-15 exhibit the best hydrogenation properties linked with the Ru-induced metallization of Mo ions in the Ru0.4Mo0.6S2 phase. This catalyst showed two-fold higher hydrogenation properties than CoMoS/γ-Al2O3 reference catalyst. The linear dependencies of initial activity on Brønsted-to-Lewis acidities ratio (from DRIFT-Py) and total metal surface exposure (from XPS) were observed.Graphical abstractGraphical abstract for this article
       
  • Dual-template synthesis of mesoporous TiO2 nanotubes with
           structure-enhanced functional photocatalytic performance
    • Abstract: Publication date: Available online 11 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Guangying He, Jinhui Zhang, Yun Hu, Zhaogao Bai, Chaohai Wei Mesoporous TiO2 nanotubes (m-TiO2-NTs) with outstanding photocatalytic performance have been successfully synthesized, for the first time, through a dual-template method. The dual-template method uses multi-walled carbon nanotube (CNT) as a hard template to control the morphology and cetyltrimethylammonium bromide (CTAB) as a soft template to form the mesoporous structure. The resulting m-TiO2-NTs are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), nitrogen adsorption-desorption and X-ray photoelectron spectroscopy (XPS). Rhodamine B (RhB) and dibutyl phthalate (DBP) are used as model pollutants to evaluate the photocatalytic properties of the new materials. The m-TiO2-NTs possess a multiple channel tubular structure and have higher specific surface area than TiO2 nanoparticles (TiO2-NPs). These features result in significantly superior photocatalytic activity for photodegradation. Specifically, the reaction rate constant for the photodegradation of RhB is 9.8 times greater with m-TiO2-NTs than it is with TiO2-NPs. In the case of DBP, the rate constant is 7.7 times higher. Photocatalytic removal ratios of gaseous acetaldehyde (CH3CHO) and the generation of COX (CO + CO2) were detected to evaluate the decomposition ability of the materials, m-TiO2-NTs showed the best CH3CHO removal efficiency and the highest CO2 selectivity. The active species of photocatalytic process are found to be •OH. In addition, the m-TiO2-NTs exhibit excellent thermal and photocatalytic stability even after six recycles. This work demonstrates a novel way to fabricate mesoporous TiO2 nanotubes that have multiple channel tubular structure and to apply them in environmental photocatalysis.Graphical abstractGraphical abstract for this article
       
  • MOF-Derived Hollow TiO2@C/FeTiO3 Nanoparticles as Photoanodes with
           enhanced Full Spectrum light PEC activities
    • Abstract: Publication date: Available online 2 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Jian Wang, Chuang Xue, Wenqing Yao, Jun Liu, Xingxing Gao, Ruilong Zong, Zhuang Yang, Wenjie Jin, Dongping Tao In the current work, the ternary TiO2@C/FeTiO3 (TCF) hollow nanotubes are synthesized using MOF-Fe nanorods as a sacrificial template and precursor via the thermal carbonization under N2 atmospheres. Due to such delicate structure features that consist of hollow needle-like framework, middle conductive-layer carbon and monodisperse FeTiO3 nanoparticles embedded on carbon layer, the hollow TCF composites can effectively harvest full spectrum light energy, enhance the interfacial charge separation and suppressed the recombination of photogenerated electron-hole pairs, resulting in enhanced photoelectrocatalytic (PEC) activity. Among as-synthesized samples, TCF-20% photoanode exhibits the best performance towards the degradation of phenol under full spectrum light irradiation with an anodic bias of 1.5 V vs. SCE and the degradation rate constant is 0.586 h-1, which is 2.75 times larger than that of the corresponding sum of both EC and PC process. In addition, triple synergistic effects of the possible mechanism with the enhancement of PEC activity was proposed on the basis of PEC degradation results. This work also opens a new insight for synthesis of photocatalysts based on novel MOFs.Graphical abstractGraphical abstract for this article
       
  • Enhanced direct deoxygenation of anisole to benzene on SiO2-supported
           Ni-Ga alloy and intermetallic compound
    • Abstract: Publication date: Available online 1 March 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Ying Zheng, Ning Zhao, Jixiang Chen Herein, Ni/SiO2 and bimetallic NixGa/SiO2 (Ni/Ga atomic ratio x = 6 and 3) catalysts were prepared by the impregnation method followed by reduction at 550 °C and tested in the vapor hydrodeoxygenation of anisole at 0.1 MPa and 300 °C. Ni-Ga alloy and Ni3Ga intermetallic compound (IMC) formed in Ni6Ga/SiO2 and Ni3Ga/SiO2, respectively, where the Ga atoms break contiguous Ni ones reducing the ensembles of Ni atoms and the H2 uptakes. Also, a charge transfer from Ga to Ni increased the electron density of Ni, and hydrogen spill-over occurred on NixGa/SiO2. In contrast to Ni/SiO2, NixGa/SiO2 improved not only the hydrodeoxygenation activity but also the selectivity to benzene. At the similar anisole conversion (˜31%), the selectivity to benzene was 75.2%, 83.0% and 92.6% on Ni/SiO2, Ni6Ga/SiO2 and Ni3Ga/SiO2, respectively. Reactivity evaluation, anisole-TPD and TPSR results show that the direct CArOCH3 bond cleavage (CAr represents the carbon in benzene ring) to benzene was more preferential on NixGa/SiO2 than on Ni/SiO2. Isotope tracing experiment indicates that the spilt-over hydrogen at the interface between the Ni3Ga particles and support participated in the reaction. We suggest that the synergetic effect between Ni and Ga facilitated the direct CArO bond cleavage. Moreover, NixGa/SiO2 were less active for benzene hydrogenation and CC bond hydrogenolysis than Ni/SiO2, contributing to higher selectivity to benzene. Significantly, methanol, derived from the direct the CArOCH3 bond cleavage, dominatingly decomposed to CO and H2 and methanation scarcely occurred on NixGa/SiO2, however, it was mainly converted to methane on Ni/SiO2. Low activities for benzene hydrogenation, CC bond hydrogenolysis and methanation on NixGa/SiO2 (especially Ni3Ga/SiO2) are attributed to the geometric and electronic effects of Ga in alloy and IMC. The finding is significant in rationally designing the catalyst with high benzene yield and low H2 consumption.Graphic abstractGraphical abstract for this article
       
  • Insights into the Role of Singlet Oxygen in the Photocatalytic Hydrogen
           Peroxide Production over Polyoxometalates-Derived Metal Oxides
           Incorporated into Graphitic Carbon Nitride Framework
    • Abstract: Publication date: Available online 13 February 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Shen Zhao, Xu Zhao To develop a new strategy of enhancing the photoinduced holes (h+) consumption to promote the photoinduced electrons (e-) utilization for O2 reduction to H2O2 and maintaining the chemical stability of g-C3N4-based catalysts, the hybrid catalyst of g-C3N4-CoWO has been prepared through the calcination of the graphitic carbon nitride (g-C3N4) precursor of 3-amino 1, 2, 4-triazole (3-AT) and the polyoxometalates (POMs) precursor of (NH4)8Co2W12O42 (NH4-Co2W12). The hybrid catalyst of g-C3N4-CoWO with well-defined and stable structure exhibits efficient catalytic performance (9.7 μmol h-1) for photocatalytic H2O2 production in the absence of organic electron donor under visible light. The value of electrons transfer during the oxygen reduction reaction (ORR) process obtained from the Koutecky-Levich plot for g-C3N4-CoWO (n = 1.95) is higher than that for g-C3N4 (n = 1.18), suggesting that the CoWO incorporated into g-C3N4 framework can generate more e- for O2 reduction. The superoxide radicals (O2-) quantitative and scavenger experiments combined with the electron spin resonance (ESR) results reveal that the negative shifts of the conduction band (CB) level from g-C3N4 to g-C3N4-CoWO can enhance the single-electron reduction of O2 to O2-. The h+ and 1O2 scavenger experiments results combined with the ESR results demonstrate that the CoWO incorporated into g-C3N4 framework can promote the oxidation of O2- to 1O2 by h+. The 1O2 quantitative experiments results indicate that the 1O2 can proceed two-electron reduction to H2O2. The enhanced h+ consumption and the 1O2 transferred from O2- can promote the photocatalytic H2O2 production over g-C3N4-CoWO. In addition, the recycle experiment results reveal that the heterogeneous g-C3N4-CoWO is catalytic stable.Graphical abstractGraphical abstract for this article
       
  • Selective Catalytic Reduction of NOx over Cu- and Fe-exchanged zeolites
           and their mechanical mixture
    • Abstract: Publication date: Available online 11 February 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Houeida Issa Hamoud, Valentin Valtchev, Marco Daturi SCR-NH3 activities of Cu-SAPO-34 (Cu-CZC) and Fe-Mordenite (Fe-MOR) and their mechanical mixture (50:50) were investigated in the temperature range 150-450 °C using operando FTIR spectroscopy. Structural and textural studies assessed the quality of the material synthesis, while in situ IR characterisation allowed the quantification of the acidic sites at the surface of the zeolites, as well as the cationic distribution inside the pores. As expected, Cu-CZC showed high NOx activity at lower temperatures (75 % of NOx conversion at T  85 %) at higher temperatures (300-450 °C). The co-presence of Cu and Fe in the mechanical mixture catalyzes the undesirable oxidation of ammonia and leads to the formation of NO, especially at high temperatures. However, the mechanical mixture of Cu-CZC and Fe-MOR has been found to efficiently operate in the presence of excess ammonia (NH3/NOx = 1.3) in a much broader temperature range comparing to the catalysts modified with only one transition metal (Fe or Cu) and also respect to a sample containing both cations in a single zeolitic framework, thus opening new opportunities in the catalytic reduction of NOx.Graphical abstractGraphical abstract for this articleHighlights
       
  • Photocatalytic, photolytic and radiolytic elimination of imidacloprid from
           aqueous solution: reaction mechanism, efficiency and economic
           considerations
    • Abstract: Publication date: Available online 24 January 2019Source: Applied Catalysis B: EnvironmentalAuthor(s): Georgina Rózsa, Máté Náfrádi, Tünde Alapi, Krisztina Schrantz, László Szabó, László Wojnárovits, Erzsébet Takács, Antal Tungler The purpose of this work was the comparison of imidacloprid transformation in heterogeneous photocatalysis (TiO2), UV254 nm photolysis, UV254 nm/VUV185 nm photolysis and γ-radiolysis (also pulse radiolysis) in the presence and absence of dissolved oxygen, and the identification of intermediates formed during the applied treatments. All the methods tested were effective in the degradation of imidacloprid in 10−4 mol dm−3 aqueous solution. In most cases the mineralization (TOC) and the disappearance of the starting molecules (detected by HPLC/DAD) occurs parallel. However, when the starting molecules were eliminated in oxygenated solutions the highest decrease in TOC values were only 30-40% in UV/VUV and TiO2/O2 systems. In radiolysis and UV photolytic systems these values were 10-15%. In the absence of oxygen the mineralization was usually slower than in its presence. Beside the dominant photocatalytic process, a small-scale contribution of direct photolysis was observed in TiO2 containing suspensions, irradiated with 300-400 nm light.Hydroxyl radicals show low reactivity with the N-containing aromatic ring, they attack the heterocyclic 5-member ring and the CH2 bridge between the two rings in direct oxidation or in H-abstraction. In these reactions carbon centred α-aminoalkyl radicals form. In the presence of dissolved oxygen these radicals transform to hydroxylated or carbonylated stable products. Scavenging experiments suggest that in TiO2 photocatalytic degradation beside hydroxyl radical based transformation, direct charge transfer has also important role in the degradation.Based on the degradation and mineralization results with imidaloprid, photocatalysis, UV/VUV photolysis and radiolysis are recommended for practical application, economic considerations (EEO) suggest radiolysis as the method requiring lowest electric energy consumption.Graphical Graphical abstract for this article
       
 
 
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