Surface Redox Dynamics in Gold–Zinc CO <sub>2</sub> Hydrogenation Catalysts
Scott R. Docherty, Оlga V. Safonova, Christophe Copéret
Abstract
Au–Zn catalysts have previously been shown to promote the hydrogenation of CO 2 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 CO 2 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 CO 2 hydrogenation catalysts and illustrate the role of these reversible processes in driving reactivity.