Oxidation of methanol on the surfaces of model Cu/ZnO catalysts containing Cu¹⁺ and Cu⁰ species

Abstract

Interaction of CH₃OH with Cu clusters deposited on ZnO films grown on a Zn foil as well as on a ZnO(0001)-Zn crystal, has been examined by X-ray photoelectron spectroscopy. On clean Cu clusters, reversible molecular adsorption or formation of CH₃O is observed. However if the Cu clusters are pretreated with oxygen, both CH₃O and HCOO^- species are produced. Model Cu/ZnO catalyst surfaces, containing both Cu¹⁺ and Cu⁰ species, show interesting oxidation properties. On a Cu⁰-rich catalyst surface, only CH₃O species is formed on interaction with CH₃OH. On a Cu¹⁺-rich surface, however, HCOO^- ion is the predominant species.