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Wang W.,University of Sichuan | Wang W.,Low Carbon Technology | Wang W.,Sichuan Provincial Engineering Technology Center for Environmental Protection Catalytic Materials | Chu W.,University of Sichuan | And 5 more authors.
International Journal of Hydrogen Energy | Year: 2016

Nickel-based catalysts supported on multi-walled carbon nanotubes (CNTs) promoted with cerium were successfully synthesized by ultrasonic-assisted co-impregnation, using γ-Al2O3 as comparative support, and employed in the carbon dioxide methanation reaction. Results indicated that the exceptional properties of CNTs together with the accession of cerium effectively enhanced the dispersion of metallic nickel, promoted the reduction of metal oxides and accelerated the CO2 activation. Meanwhile, the confinement effect of CNTs and the promotion effect of cerium could efficiently prevent the active species migration and sintering, and restricted the carbon deposition reaction. Catalytic performances exhibited that 12Ni4.5Ce/CNT catalyst possessed the highest activity with 83.8% conversion of CO2 and almost 100% selectivity of CH4 without obvious deactivation after 100 h stability test under reaction conditions. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Chu W.,Sichuan University | Chu W.,Sichuan Provincial Engineering Technology Center for Environmental Protection Catalytic Materials | Xu J.,Chongqing University of Technology | Hong J.,Sichuan University | And 3 more authors.
Catalysis Today | Year: 2015

In this paper, several types of plasma enhanced catalysts for Fischer Tropsch (FT) synthesis were investigated and discussed, in comparison of conventional catalysts, with different carriers [alumina, silica, carbon nanotubes (CNTs)], and/or different promoters (Pt, Ru), etc. For the silica-supported cobalt FT catalysts, the cobalt dispersion was significantly enhanced by plasma treatment. Nano cobalt particle size was smaller when the glow discharge plasma intensity was higher. There were similar cases for the Ru promoted FT catalysts or alumina supported FT catalysts. For the alumina supported cobalt FT catalysts, Pt addition enhanced significantly the catalysts reduction. Due to the combination of higher cobalt dispersion and optimized cobalt reducibility, plasma-assisted promoted catalysts exhibited an enhanced activity in FT synthesis. © 2015.

Lu H.,University of Sichuan | Lu H.,Sichuan Provincial Engineering Technology Center for Environmental Protection Catalytic Materials | Jiang C.,University of Sichuan | Ding Z.,University of Sichuan | And 5 more authors.
Journal of Energy Chemistry | Year: 2016

Co3O4/CeO2 composites with high surface areas and ultrafine crystalline sizes for catalytic combustion of methane were firstly prepared by a new sol-gel method which combined ultrasonic impregnation treatment and calcination in N2 atmosphere. The samples were characterized by various means such as nitrogen adsorption/desorption, X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Results showed that the modified catalyst had the mesoporous structure, comparatively higher amount of surface oxygen and larger oxygen vacancies than others. As a result of the structure and surface composition merits, a high methane combustion conversion (50%) could be obtained at a low temperature of 262°C for the modified Co3O4/CeO2 composites catalysts. The experimental results demonstrated that ultrasonic impregnation treatment combined with the N2 thermal treatment prior to calcination in air had a promising application for preparation of Co3O4/CeO2 composites catalysts for low-temperature catalytic combustion of methane. © 2016.

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