Surface Redox Dynamics in Gold–Zinc CO2 Hydrogenation Catalysts

• DOI: 10.1021/jacs.3c03522
• Publication Date: 2023-06-15T13:56:56Z
• Authors: Scott R. Docherty; Olga V. Safonova; Christophe Copéret

Au-Zn catalysts have previously been shown to promote the hydrogenation of CO2 to methanol, but their active state is poorly understood. Here, silica-supported bimetallic Au-Zn alloys, prepared by surface organometallic chemistry (SOMC), are shown to be proficient catalysts for hydrogenation of CO2 to methanol. In situ X-ray absorption spectroscopy (XAS), in conjunction with gas-switching experiments, is used to amplify subtle changes occurring at the surface of this tailored catalyst during reaction. Consequently, an Au-Zn alloy is identified and is shown to undergo subsequent reversible redox changes under reaction conditions according to multivariate curve resolution alternating least-squares (MCR-ALS) analysis. These results highlight the role of alloying and dealloying in Au-based CO2 hydrogenation catalysts and illustrate the role of these reversible processes in driving reactivity.