Influence of electronic and structural properties on Au/In2O3/ZrO2 catalysts for CO2 hydrogenation to methanol

Abstract

Hydrogenation of CO₂ to methanol using H₂ is a promising route for renewable energy production and CO₂ utilization. Meanwhile, the development of catalysts that are both active and highly selective towards methanol production remains a significant challenge. This work investigates the methanol production performance of In₂O₃, In₂O₃/ZrO₂, ZrO₂, and the corresponding Au-promoted oxides. Techniques including XPS, ex situ and operando Raman spectroscopy, in situ and operando DRIFTS, and UV–Vis spectroscopy, together with HR-TEM, revealed that the interactions among Au, InO_x, and zirconia species led to the creation of an interface for CO₂ activation and hydrogenation to methanol, facilitated by oxygen vacancies generated in a reducing atmosphere. The high dispersion of Au and indium oxide species, as shown by HR-TEM, indicated that Au clusters and/or nanoparticles (NPs), together with In₂O₃, favored H₂ dissociation and the prevention of sintering during the reaction. The 0.22Au/6.6In₂O₃/ZrO₂ sample achieved the maximum methanol yield, with superior activity and selectivity, compared to the unpromoted catalyst.