In Situ Time-Resolved Characterization of Au-CeO2 Catalysts During Water Gas Shift Reactions: presence of Au and O Vacancies in the Active Phase
Synchrotron-based in situ time-resolved x-ray diffraction and x-ray absorption spectroscopies were used to study the behavior of nanostructured {l_brace}Au+AuO{sub x}{r_brace}-CeO{sub 2} catalysts under the water-gas shift (WGS) reaction. At temperatures above 250 C, a complete AuO{sub x}{yields}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 CeO{sub 2}(111) single crystal corroborate that cationic Au{sup {delta}} 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.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 913728
- Report Number(s):
- BNL-78296-2007-JA; JCPSA6; TRN: US200804%%44
- Journal Information:
- J. Chem. Phys., Vol. 123; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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