Hydrogenation of CO2 to CH3OH on the Cu-ZnO-BaTiO3 catalysts: The electronic metal-support interaction (EMSI) induces the upshift of the d-band center of Cu atoms in Cu-based catalysts

Abstract

The study of catalysts for the efficient hydrogenation of CO₂ to methanol is imperative for the reduction of atmospheric CO₂ content. In this paper, Cu-based catalysts with different supports loadings were prepared by deposition precipitation method. The purpose of this study was to investigate the reasons for the shift of the d-band center of Cu atoms in Cu-based catalysts and its effect on the catalytic activity of CO₂ hydrogenation to methanol. In situ XPS and CO-DRIFTS characterization demonstrated that the content of coordinatively unsaturated Cu⁰ step-edge sites is identified as a structural descriptor for the catalyst d-band center.

Electrons transfer from supports to Cu (EMSI) favored the formation of coordinatively unsaturated Cu⁰ step-edge sites, which in turn resulted in the upshift of the catalyst d-band center. The direction and degree of electrons transfer between the supports and Cu were determined by the supports’ energy-band structure. Experiments involving H₂-TPD and catalytic activity demonstrated that the upshift of the d-band center enhanced the adsorption strength of the catalyst for H₂ and improved the catalytic activity.