Mechanism of CO oxidation reaction on O-covered Pd(111) surfaces studied with fast x-ray photoelectron spectroscopy: Change of reaction path accompanying phase transition of O domains
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
We studied the mechanism of CO oxidation on O-precovered Pd(111) surfaces by means of fast x-ray photoelectron spectroscopy (XPS). The oxygen overlayer is compressed upon CO coadsorption from a p(2x2) structure into a ({radical}3x{radical}3)R30 deg. structure and then into a p(2x1) structure with increasing CO coverage. These three O phases exhibit distinctly different reactivities. (1) The p(2x2) phase does not react with CO unless the surface temperature is sufficiently high (<290 K). (2) In the ({radical}3x{radical}3)R30 deg. phase, the reaction occurs exclusively at island peripheries. CO molecules in a high-density phase formed under CO exposure react with oxygen atoms, leading to quite a small apparent activation energy. (3) The reaction proceeds uniformly over the islands in the p(2x1) phase.
- OSTI ID:
- 20783307
- Journal Information:
- Journal of Chemical Physics, Vol. 124, Issue 22; Other Information: DOI: 10.1063/1.2205856; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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