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A Ni/CeO2-CDC-SiC Catalyst with Improved Coke Resistance in CO2 Reforming of Methane Yu Guo, Junma Zou, Xiao Shi, Patrick Rukundo, and Zhou-jun Wang ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.6b02661 • Publication Date (Web): 22 Jan 2017 Downloaded from http://pubs.acs.org on January 23, 2017
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ACS Sustainable Chemistry & Engineering
A Ni/CeO2-CDC-SiC Catalyst with Improved Coke Resistance in CO2 Reforming of Methane Yu Guo, Junma Zou, Xiao Shi, Patrick Rukundo, Zhou-jun Wang*,a,b a
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical
Technology, 15 Beisanhuan East Road, Beijing 100029, P. R. China b
Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical
Technology, 15 Beisanhuan East Road, Beijing 100029, P. R. China
*Corresponding Author
Dr. Zhou-jun Wang
E-mail address:
[email protected], Tel./Fax: +86 10 64437983
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ACS Sustainable Chemistry & Engineering
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ABSTRACT: A nanocomposite Ni/CeO2-CDC-SiC catalyst which consists of highly dispersed Ni nanoparticles contacting intimately with CeO2 nanoparticles on a nanoporous carbide-derived carbon (CDC) layer over SiC support has been successfully designed for carbon dioxide (CO2) reforming of methane. In comparison with the Ni/CDC-SiC catalyst, the ceria-promoted Ni/CDCSiC catalyst possessed enhanced activity and improved stability. The catalysts were systematically characterized with N2 sorption, X-ray diffraction, transmission electron microscopy, energydispersive X-ray spectrometry elemental mapping, thermogravimetric/differential thermal analysis, temperature-programmed reduction, and X-ray photoelectron spectroscopy measurements. It was found that, after introducing CeO2 promoter, the specific surface area was increased and a smaller Ni particle size was obtained. The smaller Ni particle size led to an enhanced reforming activity. The presence of abundant Ni-CeO2 interfaces on the CeO2-promoted catalyst accelerated the carbon removal through the lattice oxygen species, which resulted in superior carbon resistance and thus an improved stability. The outcome of the present work is expected to shed meaningful insight into the design of nanocomposite catalysts with the aid of metal-oxide interfaces.
KEYWORDS: Greenhouse gas, Syngas, Silicon carbide, Ceria, Nickel, Reforming, Interface, Size
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ACS Sustainable Chemistry & Engineering
INTRODUCTION Nowadays, energy crisis and environmental pollution have become two imperative problems for the human beings.1,2 In this context, carbon dioxide (CO2) reforming of methane has drawn significant attention worldwide since this technology can convert two potent greenhouse gases (CH4/CO2) into valuable syngas (H2/CO) for clean energy production.3,4 To date, commercialization of this technology has still not been realized mainly due to the lack of feasible catalysts. The currently investigated catalysts can be divided into transition- and noble- metal based catalysts. Compared with the noble-metal based catalysts, the cheaper and more abundant transition-metal based catalysts, particularly Ni based catalysts, become more competitive for industrial applications.5,6 Unfortunately, Ni catalysts inevitably deactivate because of metal sintering and/or carbon deposition.7 Therefore, design of novel Ni catalysts with enhanced activity and improved stability is of great urgency. Recently more and more works have documented that the support could be a key factor that influences the catalytic performance of supported metal catalysts.8 Silicon carbide (SiC) as a novel catalytic support has attracted much attention due to its appropriate chemical inertness, superior thermal conductivity and good mechanical strength.9-11 Nevertheless, the commercial SiC always possesses a limited specific surface area (
