In situ time-resolved characterization of Au-Ce O 2 and Au O x -Ce O 2 catalysts during the water-gas shift reaction: Presence of Au and O vacancies in the active phase

X. Wang; J. A. Rodriguez; J. C. Hanson; M. Ṕrez; J. Evans

doi:10.1063/1.2136876

In situ time-resolved characterization of Au-Ce O ₂ and Au O _x -Ce O ₂ catalysts during the water-gas shift reaction: Presence of Au and O vacancies in the active phase

X. Wang, J. A. Rodriguez, J. C. Hanson, M. Ṕrez, J. Evans

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Abstract

Synchrotron-based in situ time-resolved x-ray diffraction and x-ray absorption spectroscopies were used to study the behavior of nanostructured {Au+Au Ox } -Ce O2 catalysts under the water-gas shift (WGS) reaction. At temperatures above 250 °C, a complete Au Ox →Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au nanoparticles supported on rough ceria films or a Ce O2 (111) single crystal corroborate that cationic Auδ+ species cannot be the key sites responsible for the WGS activity at high temperatures. The rate determining steps for the WGS seem to occur at the gold-ceria interface, with the active sites involving small gold clusters (<2 nm) and O vacancies.

Original language	English (US)
Article number	221101
Journal	Journal of Chemical Physics
Volume	123
Issue number	22
DOIs	https://doi.org/10.1063/1.2136876
State	Published - 2005
Externally published	Yes

All Science Journal Classification (ASJC) codes

General Physics and Astronomy
Physical and Theoretical Chemistry

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@article{d86a8d9803ed4b1da9d21da417473835,

title = "In situ time-resolved characterization of Au-Ce O 2 and Au O x -Ce O 2 catalysts during the water-gas shift reaction: Presence of Au and O vacancies in the active phase",

abstract = "Synchrotron-based in situ time-resolved x-ray diffraction and x-ray absorption spectroscopies were used to study the behavior of nanostructured {Au+Au Ox } -Ce O2 catalysts under the water-gas shift (WGS) reaction. At temperatures above 250 °C, a complete Au Ox →Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au nanoparticles supported on rough ceria films or a Ce O2 (111) single crystal corroborate that cationic Auδ+ species cannot be the key sites responsible for the WGS activity at high temperatures. The rate determining steps for the WGS seem to occur at the gold-ceria interface, with the active sites involving small gold clusters (<2 nm) and O vacancies.",

author = "X. Wang and Rodriguez, {J. A.} and Hanson, {J. C.} and M. Ṕrez and J. Evans",

note = "Funding Information: The authors are grateful to M. Flytzani-Stephanopoulos for thought provoking conversations about the water-gas shift reaction on Au-ceria systems and to W. Deng for preparing the nanostructured catalysts studied in this work. The work done at BNL was financed by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886. The NSLS is supported by the Divisions of Chemical and Materials Science of the U.S. Department of Energy . Two of the authors (M.P. and J.E.) thank INTEVEP for a research grant that made possible part of this work.",

year = "2005",

doi = "10.1063/1.2136876",

language = "English (US)",

volume = "123",

journal = "Journal of Chemical Physics",

issn = "0021-9606",

publisher = "American Institute of Physics",

number = "22",

}

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T1 - In situ time-resolved characterization of Au-Ce O 2 and Au O x -Ce O 2 catalysts during the water-gas shift reaction

T2 - Presence of Au and O vacancies in the active phase

AU - Wang, X.

AU - Rodriguez, J. A.

AU - Hanson, J. C.

AU - Ṕrez, M.

AU - Evans, J.

N1 - Funding Information: The authors are grateful to M. Flytzani-Stephanopoulos for thought provoking conversations about the water-gas shift reaction on Au-ceria systems and to W. Deng for preparing the nanostructured catalysts studied in this work. The work done at BNL was financed by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886. The NSLS is supported by the Divisions of Chemical and Materials Science of the U.S. Department of Energy . Two of the authors (M.P. and J.E.) thank INTEVEP for a research grant that made possible part of this work.

PY - 2005

Y1 - 2005

N2 - Synchrotron-based in situ time-resolved x-ray diffraction and x-ray absorption spectroscopies were used to study the behavior of nanostructured {Au+Au Ox } -Ce O2 catalysts under the water-gas shift (WGS) reaction. At temperatures above 250 °C, a complete Au Ox →Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au nanoparticles supported on rough ceria films or a Ce O2 (111) single crystal corroborate that cationic Auδ+ species cannot be the key sites responsible for the WGS activity at high temperatures. The rate determining steps for the WGS seem to occur at the gold-ceria interface, with the active sites involving small gold clusters (<2 nm) and O vacancies.

AB - Synchrotron-based in situ time-resolved x-ray diffraction and x-ray absorption spectroscopies were used to study the behavior of nanostructured {Au+Au Ox } -Ce O2 catalysts under the water-gas shift (WGS) reaction. At temperatures above 250 °C, a complete Au Ox →Au transformation was observed with high catalytic activity. Photoemission results for the oxidation and reduction of Au nanoparticles supported on rough ceria films or a Ce O2 (111) single crystal corroborate that cationic Auδ+ species cannot be the key sites responsible for the WGS activity at high temperatures. The rate determining steps for the WGS seem to occur at the gold-ceria interface, with the active sites involving small gold clusters (<2 nm) and O vacancies.

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In situ time-resolved characterization of Au-Ce O ₂ and Au O _x -Ce O ₂ catalysts during the water-gas shift reaction: Presence of Au and O vacancies in the active phase

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