CO Oxidation on Au/FePO4 Catalyst: Reaction Pathways and Nature of Au Sites
In situ FTIR spectroscopy coupled with downstream mass spectrometry has been used to clarify the pathways for room temperature (rt) CO oxidation over iron phosphate-supported Au catalyst. The charge state of Au on Au/FePO{sub 4} after calcination, reduction, or under reaction conditions was assessed by both FTIR spectroscopy (CO probing) and X-ray absorption near edge spectroscopy (XANES). Results from both approaches show that cationic gold species dominate the surface after pretreatment in O{sub 2} at 200 C. A portion of the cationic gold on Au/FePO{sub 4} can be reduced by the initial CO adsorption at rt, and subsequently repeated CO exposures do not reduce the remaining cationic Au. FTIR and Raman results from cycled CO reduction and O{sub 2} reoxidation of Au/FePO{sub 4} indicate that there are active structural oxygen species on the surface of Au/FePO4that can be consumed by CO and then replenished by gaseous O{sub 2} at rt. Au activates both CO and O{sub 2} so that the FePO{sub 4} support can undergo reduction (by CO) and reoxidation (by O{sub 2}) cycles. The results of CO oxidation with labeled {sup 18}O{sub 2} suggest the operation of two parallel reaction pathways at rt: (1) a redox pathway in which FePO{sub 4} supplies active oxygen and (2) a direct pathway on metallic Au, via either Langmuir-Hinshelwood or Eley-Rideal mechanism, in which gas phase O{sub 2} provides the active oxygen.
- 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:
- 980067
- Report Number(s):
- BNL-92985-2010-JA; JCTLA5; TRN: US201015%%1452
- Journal Information:
- Journal of Catalysis, Vol. 266, Issue 1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
Similar Records
Methanol synthesis on ZnO(0001{sup ¯}). IV. Reaction mechanisms and electronic structure
Oxygen diffusion and reactivity at low temperature on bare amorphous olivine-type silicate