ANOMALOUS BEHAVIOR OF RU FOR CATALYTIC-OXIDATION - A THEORETICAL-STUDY OF THE CATALYTIC REACTION CO+1 2O(2)-]CO2/

Recent experiments revealed an anomalous dependence of carbon monoxide oxidation at Ru(0001) on oxygen pressure and a particularly high reac tion rate. Below we report density functional theory calculations of t he energetics and reaction pathways of the speculated mechanism. We wi ll show that the exceptionally high rate is actuated by a weakly but n evertheless well bound (1 x 1)-oxygen adsorbate layer. Furthermore, it is found that reactions via scattering of gas-phase CO at the oxygen covered surface may play an important role. Our analysis reveals, howe ver, that reactions via adsorbed CO molecules (the so-called Langmuir- Hinshelwood mechanism) dominate.