CO adsorption on clean and atomic-layer-Cu-covered ZnO(101̄0) surfaces

The adsorption at room temperature of CO on clean and atomic-layer-Cu-covered ZnO(101̄0) surfaces was studied by temperature-programmed desorption (TPD). Submonolayer amounts of Cu on the surface enhance the ability of ZnO to adsorb CO drastically. A small amount of CO2 desorbed from the surface as a result of CO reaction with surface oxygen. A desorption order of 2 and a desorption activation energy of about 60 kJ/mol were obtained for CO desorption from the Cu-covered ZnO(101̄0) surface, which is in good agreement with the binding energy of CO adsorbed on Cu(100) surfaces.