CO oxidation over ZnO films on Pt(111) at near-atmospheric pressures

Well-ordered ultrathin ZnO(0001) films were grown on Pt(111) in a layer-by-layer mode. The reactivity of the films as a function of the film thickness and coverage was examined by the CO oxidation reaction at near-atmospheric pressures. At low temperatures ( 450 K), CO2 production is found to be much higher on the films of partial coverage than on dense ZnO(0001) films and bare Pt(111). Under reaction conditions, monolayer islands and an entire monolayer film transform into two-monolayers-thick islands, which dominate the surface of the active catalysts. The results provide an adequate structural model for elucidating the reaction mechanism on the oxide/metal boundary at technologically relevant