Anomalous Behavior of Ru for Catalytic Oxidation: A Theoretical Study of the Catalytic Reaction CO + 1/2 O_2 --> CO_2

摘要

Recent experiments revealed an anomalous dependence of carbon monoxideoxidation at Ru(0001) on oxygen pressure and a particularly high reaction rate.Below we report density functional theory calculations of the energetics andreaction pathways of the speculated mechanism. We will show that theexceptionally high rate is actuated by a weakly but nevertheless well bound(1x1) oxygen adsorbate layer. Furthermore it is found that reactions viascattering of gas-phase CO at the oxygen covered surface may play an importantrole. Our analysis reveals, however, that reactions via adsorbed CO molecules(the so-called Langmuir-Hinshelwood mechanism) dominate.