Reactivity of the Cu2O(1Â 0Â 0) surface: Insights from first principles calculations

We present a summary of results of systematic first principles calculations of the electronic and geometric structures of the Cu2O(1 0 0) surface and the process of CO oxidation on this surface (energetics and pathways of adsorption, diffusion and reactions of CO and O2 on the surface). The (p, T) phase diagram of the Cu2O(1 0 0) in equilibrium of with gas phase O2 built using the ab initio thermodynamics approach suggests that the O-terminated surface is preferred over the Cu-terminated one within the entire ranges of pressures and temperatures in which the compound exists. Metastable Cu-terminated Cu2O(1 0 0) is found to undergo a surface reconstruction in agreement with experiment. We find CO to oxidize spontaneously on the O-terminated Cu2O(1 0 0) surface by consuming surface O atoms. Our calculations also show that the surface O-vacancies left in the course of the CO oxidation can be easily filled with dissociative adsorption of the gas phase O2 molecules, which are usually present in reaction environment.