XPS studies of Cu/ZnO/Al2O3 ultra-fine catalysts derived by a novel gel oxalate co-precipitation for methanol synthesis by CO2+H2

Abstract The chemical states of Cu and Zn in an ultra-fine high performance Cu/ZnO/Al 2 O 3 catalyst at various preparation stages for the methanol synthesis by CO 2 /H 2 were investigated by X-ray photoelectron spectroscopy. It was found that copper was presented as metallic state and zinc still as ZnO during reaction or reduction. Moreover, it shows that the metallic Cu can be partially oxidized to Cu δ + species by pure CO 2 . The active center of the Cu/ZnO/Al 2 O 3 catalyst for methanol synthesis was discussed.