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 languageEnglish (US)
Article number221101
JournalJournal of Chemical Physics
Volume123
Issue number22
DOIs
StatePublished - 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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