Enhancing CO ₂ Hydrogenation to Methanol at Tunable Cu–ZnO Interfaces on Hydrotalcite-Derived Cu Nanocatalysts

The hydrogenation of CO 2 to methanol serves as a practical approach extensively applied in achieving carbon cycling utilization and reducing carbon emissions. Nevertheless, the rational design of Cu-based catalysts with satisfactory catalytic performance and corresponding structure–activity relationship understanding still remains a challenging goal. Inspired by the characteristics of both hydrotalcite structures and active Cu species for CO 2 hydrogenation, a series of hydrotalcite-derived Cu nanocatalysts with highly dispersed Cu nanoclusters and tunable electronic and geometric structures are obtained via simply controlling structural topological transformation process temperature, verified by a comprehensive study including Bader charge analyses, TG-MS, HAADF-STEM, in situ CO–DRIFTS, and XAFS experiments. The optimized catalyst demonstrates an exceptional normalized CO 2 reaction rate of 30.6 mmol·g cat –1 ·h –1 and a methanol selectivity of 92%, yielding an excellent methanol space-time yield (∼0.9 g·g cat –1 ·h –1 ) and a stability of 100 h under mild conditions (220 °C, 3 MPa). This is approximately twice that of the control catalyst and ranks among the top outcomes reported so far for Cu-based systems. Operando FTIR, structure–activity relationship, and DFT studies elucidate that the active Cu species at the Cu–ZnO interface function as intrinsic active centers, accelerating the formation of key intermediates (HCOO* and H 3 CO*), leading to a lower activation-energy barrier. Therefore, this work presents an effective strategy for fabricating Cu nanocatalysts featuring a precisely controllable Cu–ZnO interface via a facile LDH topological transformation, offering a promising application path in the large-scale synthesis of methanol from CO 2 hydrogenation.