Surface Redox Dynamics in Gold-Zinc CO2 Hydrogenation Catalysts

Au-Zn catalysts have previously been shown topromote thehydrogenation of CO2 to methanol, but their active stateis poorly understood. Here, silica-supported bimetallic Au-Znalloys, prepared by surface organometallic chemistry (SOMC), are shownto be proficient catalysts for hydrogenation of CO2 tomethanol. In situ X-ray absorption spectroscopy (XAS),in conjunction with gas-switching experiments, is used to amplifysubtle changes occurring at the surface of this tailored catalystduring reaction. Consequently, an Au-Zn alloy is identifiedand is shown to undergo subsequent reversible redox changes underreaction conditions according to multivariate curve resolution alternatingleast-squares (MCR-ALS) analysis. These results highlight the roleof alloying and dealloying in Au-based CO2 hydrogenationcatalysts and illustrate the role of these reversible processes indriving reactivity.

Automated summary

This study investigates the active state of Au-Zn catalysts for CO2 hydrogenation to methanol. Silica-supported bimetallic Au-Zn alloys, prepared by surface organometallic chemistry (SOMC), are shown to be efficient catalysts for CO2 hydrogenation to methanol. In situ X-ray absorption spectroscopy (XAS), together with gas-switching experiments, amplifies subtle changes occurring at the surface of the catalyst. Multivariate curve resolution alternating least-squares (MCR-ALS) analysis identifies an Au-Zn alloy and reveals its reversible redox changes under reaction conditions. These findings highlight the role of alloying and dealloying in Au-based CO2 hydrogenation catalysts and the significance of reversible processes in driving reactivity.