Mechanism of the reverse water gas shift reaction over Cu/ZnO catalyst*1

The reverse water gas shift reaction (RWGS) and the reaction with CO2 alone were carried out over a Cu/ZnO catalyst. The surface of the catalyst was characterized by N2O titration, XPS, and FT-IR spectroscopy. CO2 dissociated to give CO and the surface oxygen species. Surface Cu(I) oxide was formed by the reaction with CO2. The oxygen species were hydrogenated to H2O and the surface Cu(I) oxide was reduced to metallic Cu. It is suggested that the RWGS reaction proceeds through surface oxidation and reduction with CO2 and H2, and the dissociation of CO2 is the rate determining step.