Place exchange during surface oxidation of platinum

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:538966

You, H; Nagy, Z ^[1]

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1. Argonne National Lab., IL (United States)

We carried out an in situ examination of the incipient anodic oxidation of Pt(III) using synchrotron x-ray reflectivity techniques. We found that below a critical surface coverage the oxidation/reduction process was structurally reversible. The oxidized surface could be successfully modeled assuming a place-exchange mechanism involving the lifting of Pt atoms in the surface layer. We offer a tentative model in the frame work of the long-proposed three-step process. (I) Approximately 1/3 monolayer OH electrosorbs on the surface at 0.8V in the voltammogram where the charge transfer is approximately 0.3e{sup -}/Pt. (II) The second oxidation step will occur only at much higher potential (starting around IV) when the place exchange occurs. (III) The third oxidation step occurs by converting Pt-OH to Pt-O. Further details of the model will be discussed.

• OSTI ID: 538966
• Report Number(s): CONF-960807--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ELECTRIC POTENTIAL
OXIDATION
PLATINUM
REDUCTION
REFLECTIVITY