Tuning CO2 Hydrogenation Selectivity Through Metal–Support Interactions in Cu/CeO2 and Cu/Ce(Zr)O2 Catalysts

Abstract

Cu‐based catalysts on reducible oxides are promising for CO2 hydrogenation, but their activity and selectivity depend strongly on metal‐support interactions. Here, we investigate Cu/CeO2 and Cu/Ce0.5Zr0.5O2 catalysts with Cu loadings between 3.5 and 10 wt.% to elucidate how support composition governs the balance between reverse water‐gas shift and methanol synthesis. Structural and redox characterization by XRD, TEM‐EDX, XPS, H2‐TPR, N2O reactive frontal chromatography, and operando Cu K‐edge XAS reveals highly dispersed surface Cu species stabilized by strong interaction with the ceria‐based supports, while larger Cu particles form only above the stabilization limit. The presence of metal Cu promotes partial reduction of cerium oxide and the formation of oxygen vacancies at relatively low temperature. In RWGS, the rate scales with surface Cu concentration, confirming the importance of accessible metallic Cu sites, whereas the apparent activation barrier is linked to oxygen vacancy regeneration in the support. Under methanol synthesis conditions, Cu/CeO2 catalysts are found to outperform Cu/Ce(Zr)O2 ones. This is attributed to the higher surface oxygen‐vacancy density of CeO2, that compensates for a lower Cu dispersion. These results show that tuning the interplay between Cu surface density and reducible support chemistry provides a route to control selectivity in CO2 hydrogenation.