Deciphering Binary and Ternary Interaction Effects in Inverse Cu–ZnO–ZrO 2 Catalysts for CO 2 Hydrogenation to Methanol

Inverse Cu–ZnO–ZrO 2 catalysts have emerged as promising candidates for CO 2 hydrogenation to methanol, with enhanced methanol yields attributed to interfacial active sites. Despite growing interest, the exact role of these sites present in the inverse configuration remains unexplored. In this study, the energetics of multiple reaction pathways for CO 2 hydrogenation to methanol were investigated over the inverse Cu–ZnO–ZrO 2 (ZZ/Cu), ZrO 2 /Cu (Zr/Cu), and ZnO/Cu (Zn/Cu) catalysts using density functional theory calculations. Mechanistic analysis reveals CO 2 hydrogenation to methanol to be favored via the carboxylic (COOH) pathway on ZZ/Cu and Zn/Cu catalysts, while the formate (HCOO) pathway is favored on Zr/Cu. Although COOH formation and its dissociation to CO is favored on the Zr/Cu surface, CO hydrogenation is kinetically limited. The strong binding of the key intermediates –CO and methoxy (CH 3 O) and their high hydrogenation barriers lead to catalyst surface poisoning and lower methanol yields on the Zr/Cu surface. The presence of the ternary Zn–Zr–Cu site in ZZ/Cu balances the adsorption strengths of the intermediates and promotes hydrogenation, leading to enhanced methanol yields. The mechanistic insights gained from this study reveal the active role of inverse ZnO–ZrO 2 overlayers on Cu and will serve as a guide for the design of multicomponent catalysts for selective conversion of CO 2 to methanol.