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Correlating NEXAFS characterization of Co–W and Ni–W bimetallic carbide catalysts with reactivity for dry reforming of methane

Paper ID Volume ID Publish Year Pages File Format Full-Text
42642 45935 2009 5 PDF Available
Title
Correlating NEXAFS characterization of Co–W and Ni–W bimetallic carbide catalysts with reactivity for dry reforming of methane
Abstract

The effect of temperature on the structure and performance of Co–W–C and Ni–W–C catalysts for dry reforming of methane (DRM) has been investigated using both reactors and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. For Co–W–C, the DRM reactivity is greatly improved after being exposed to methane at 850 °C. For Ni–W–C, however, the catalytic performance before such exposure is good, although no obvious difference has been found in the catalytic performance before and after exposure to methane at 850 °C. In this work, NEXAFS has been applied to characterize the fresh and spent catalysts, both before and after exposure to the reactants at 850 °C, for both Co–W–C and Ni–W–C. Three NEXAFS regions have been investigated for each catalyst: the carbon K-edge, the oxygen K-edge and the L-edge of either cobalt or nickel. NEXAFS results provide insights into the possible origins for the different performance of those two different carbides. To exhibit reasonable reactivity for DRM, Ni–W oxide and Co–W oxide are required to be reduced, and the active stable catalysts must contain large amounts of carbon so that WC and either Ni or Co are seen in the bulk. NEXAFS results indicate that Ni–W–C can be reduced to a greater extent and at a lower temperature than Co–W–C. In addition, NEXAFS measurements reveal the formation of graphitic carbon at or near the surface region. This species can play a critical role in the reactivity and stability of the catalysts for DRM.

Graphical abstractThe effect of temperature on the structure and performance of Co–W–C and Ni–W–C catalysts for dry reforming of methane has been investigated using both reactors and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Ni–W–C is reduced more than Co–W–C. Graphitic carbon formed at or near the surface region plays a critical role in the reactivity and stability of the catalysts.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Bimetallic carbide; Dry reforming; Methane; NEXAFS
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Correlating NEXAFS characterization of Co–W and Ni–W bimetallic carbide catalysts with reactivity for dry reforming of methane
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 356, Issue 1, 1 March 2009, Pages 18–22
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us