Colloidal Control of the Cu–ZnO Interface for Catalytic CO ₂ Hydrogenation to Methanol

In this work, we report the rational design of Cu@ZnO nanocatalysts (NCs) via a robust one-pot, two-step synthesis. The resulting NCs display two distinct morphologies, cubes and spheres, with tunable ZnO coverage. By precisely adjusting key synthesis parameters, controlled ZnO domain formation was achieved on Cu seeds of varying crystallinity and shape. Structural and chemical characterization provide insights into the ZnO nucleation process, which is influenced by the crystallinity of the Cu seeds. In addition, the presence of oxidized copper species (Cu2O and CuO) at the Cu–ZnO interface is consistently observed, indicating their involvement in ZnO domain formation and interfacial structuring. The catalytic performance of these nanostructures was evaluated in CO2 hydrogenation to methanol under high-pressure conditions (31 bar). The results reveal clear correlations between catalyst morphology, Cu–ZnO interfacial density, and catalytic performance. In particular, catalysts consisting of Cu nanoparticles exposing (100) facets and higher interfacial densities are associated with enhanced methanol yield and reduced byproduct formation. This work establishes a versatile synthetic platform that not only provides high-quality nanocatalysts with tunable interfaces but also offers fundamental insights into structure–activity relationships in CO2 hydrogenation to methanol.