EVIDENCE FOR A SURFACE-REACTION BETWEEN H AND CO ADSORBED ON POLYCRYSTALLINE PT

Temperature programmed desorption (TPD) experiments have been performe d after dosing an ion-sputtered and annealed polycrystalline Pt surfac e with CO and H-2. The GO-dosing was done both sequentially and simult aneously. With increasing residence time on the surface, the H-2-TPD s pectra exhibit conversion of the original H-2-like features to feature s similar to the CO-TPD peaks. This provides evidence for the formatio n of a CO/H surface species through a chemical reaction between adsorb ed H and adsorbed CO. The reaction occurs more rapidly when the sample is dosed or held at elevated temperatures, indicating that the reacti on is activated.