The adsorption of oxygen at 500°C on a Pt50Rh50(100) single crystal surface was studied using UHV-STM and Auger electron spectroscopy. Images were taken of the p(3x1) phase, of a mixed phase with p(2x2), c(2x2) and (3x3) units and of rhodium oxide patches. Possible models for these structures involving surface reconstruction are presented. Exposure of the p(3x1)O/PtRh(100) to H2 at room temperature led to the conversion to the p(1x1) substrate structure. The ordering and composition of this substrate structure after reduction is discussed.
Corresponding author: M. Schmid (schmid).
Users with online access to Surf. Sci. can load the article from the publisher.