Enhancement of the Catalytic Performance and Active Site Clarification of Cu/ZnO Based Catalysts for Methanol Synthesis by CO₂ Hydrogenation

Abstract

The active site and the role of ZnO in Cu/ZnO-based catalysts for methanol synthesis from CO₂ and H₂ were investigated using both classical catalytic and surface science techniques. The active site model in which Zn species present on the Cu surface promotes methanol synthesis is proposed based on the findings for the powder catalysts such as a physical mixture of Cu/SiO₂ and ZnO/SiO₂. Zn promotion was confirmed with a model catalyst of a Zn-deposited Cu(111) surface. The mechanism and kinetics of methanol synthesis over Zn/Cu(111) as well as the structure of the active site were studied. Metallic Cu–Zn surface alloy acts a catalytically active species for the methanol synthesis from CO₂ and H₂. Furthermore, we describe the improvement of catalyst performance and development of catalytic processes based on these findings.