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Title: Determination of CO, H{sub 2}O and H{sub 2} coverage by XANES and EXAFS on Pt and Au during water gas shift reaction.

Abstract

The turn over rate (TOR) for the water gas shift (WGS) reaction at 200C, 7%CO, 9%CO{sub 2}, 22% H{sub 2}O, 37% H, and balance Ar, of 1.4 nm Au/Al{sub 2}O{sub 3} is approximately 20 times higher than that of 1.6 nm Pt.Al{sub 2}O{sub 3}. Operando EXFAS experiments at both the Au and Pt L{sub 3} edges reveal tht under reaction conditions, the catalysts are fully metallic. In the absence of adsorbates, the metal-metal bond distance of Pt and Au catalysts are 0.07 {angstrom} and 0.13 {angstrom} smaller than those of bulk Pt and Au foils, respectively. Adsorption of H{sub 2} or CO on the Pt catalysts leads to significantly longer Pt-Pt bond distances, while there is little change in the Au-Au bond distance with adsorbates. Adsorption of CO, H{sub 2} and H{sub 2}O leads to changes in the XANES spectra that can be used to determine the surface coverage of each adsorbate under reaction conditions. During WGS, the coverage of CO, H{sub 2}O and H{sub 2} are obtained by the linear combination fitting of the difference XANES or {Delta}XANES, spectra. Pt catalysts adsorb CO,H{sub 2} and H{sub 2}O more strongly than the Au, in agreement with the lower CO reactionmore » order and higher reaction temperatures.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
982666
Report Number(s):
ANL/CSE/JA-65919
Journal ID: 1463-9076; TRN: US201015%%1273
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Phys. Chem. Chem. Phys.
Additional Journal Information:
Journal Volume: 12; Journal Issue: 21 ; 2010
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; BALANCES; CATALYSTS; DISTANCE; FOILS; SPECTRA; SURFACES; WATER GAS

Citation Formats

Guo, N, Fingland, B R, Williams, W D, Kispersky, V F, Jelic, J, Delgass, W N, Ribeiro, F H, Meyer, R J, Miller, J T, Purdue Univ., and Univ. of Illinois. Determination of CO, H{sub 2}O and H{sub 2} coverage by XANES and EXAFS on Pt and Au during water gas shift reaction.. United States: N. p., 2010. Web. doi:10.1039/c000240m.
Guo, N, Fingland, B R, Williams, W D, Kispersky, V F, Jelic, J, Delgass, W N, Ribeiro, F H, Meyer, R J, Miller, J T, Purdue Univ., & Univ. of Illinois. Determination of CO, H{sub 2}O and H{sub 2} coverage by XANES and EXAFS on Pt and Au during water gas shift reaction.. United States. https://doi.org/10.1039/c000240m
Guo, N, Fingland, B R, Williams, W D, Kispersky, V F, Jelic, J, Delgass, W N, Ribeiro, F H, Meyer, R J, Miller, J T, Purdue Univ., and Univ. of Illinois. Fri . "Determination of CO, H{sub 2}O and H{sub 2} coverage by XANES and EXAFS on Pt and Au during water gas shift reaction.". United States. https://doi.org/10.1039/c000240m.
@article{osti_982666,
title = {Determination of CO, H{sub 2}O and H{sub 2} coverage by XANES and EXAFS on Pt and Au during water gas shift reaction.},
author = {Guo, N and Fingland, B R and Williams, W D and Kispersky, V F and Jelic, J and Delgass, W N and Ribeiro, F H and Meyer, R J and Miller, J T and Purdue Univ. and Univ. of Illinois},
abstractNote = {The turn over rate (TOR) for the water gas shift (WGS) reaction at 200C, 7%CO, 9%CO{sub 2}, 22% H{sub 2}O, 37% H, and balance Ar, of 1.4 nm Au/Al{sub 2}O{sub 3} is approximately 20 times higher than that of 1.6 nm Pt.Al{sub 2}O{sub 3}. Operando EXFAS experiments at both the Au and Pt L{sub 3} edges reveal tht under reaction conditions, the catalysts are fully metallic. In the absence of adsorbates, the metal-metal bond distance of Pt and Au catalysts are 0.07 {angstrom} and 0.13 {angstrom} smaller than those of bulk Pt and Au foils, respectively. Adsorption of H{sub 2} or CO on the Pt catalysts leads to significantly longer Pt-Pt bond distances, while there is little change in the Au-Au bond distance with adsorbates. Adsorption of CO, H{sub 2} and H{sub 2}O leads to changes in the XANES spectra that can be used to determine the surface coverage of each adsorbate under reaction conditions. During WGS, the coverage of CO, H{sub 2}O and H{sub 2} are obtained by the linear combination fitting of the difference XANES or {Delta}XANES, spectra. Pt catalysts adsorb CO,H{sub 2} and H{sub 2}O more strongly than the Au, in agreement with the lower CO reaction order and higher reaction temperatures.},
doi = {10.1039/c000240m},
url = {https://www.osti.gov/biblio/982666}, journal = {Phys. Chem. Chem. Phys.},
number = 21 ; 2010,
volume = 12,
place = {United States},
year = {2010},
month = {1}
}