Using core level spectroscopy and density functional theory we show that a onedimensional (1D) PtO2 oxide structure forms at the steps of the Pt(332) surface after O2 exposure. The 1D oxide is found to be stable in an oxygen pressure range, where bulk oxides are only meta-stable, and is therefore argued to be a precursor to the Pt oxidation. As an example of the consequences of such a precursor exclusively present at the steps, we investigate with CLS and DFT the reaction of CO with the oxygen covered Pt(332). Albeit more strongly bound, the oxidic oxygen is found to be more easily reacted off by CO than the oxygen chemisorbed on the Pt terraces.
Corresponding author: A. Mikkelsen. Reprints also available from M. Schmid (schmid).
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