Engineering Hydrogen Spillover via Zn Doping in Cu-ZnCeO _<i>z</i> Solid Solutions for Efficient Low-Temperature Methanol Synthesis

Selective hydrogenation of CO2 to methanol at low temperatures is kinetically restricted by the scarcity of active hydrogen species on oxide surfaces. Herein, we constructed a series of Cu-supported ZnCeOz solid-solution catalysts and precisely tuned the hydrogen spillover capability by regulating the Zn doping level in the CeO2 lattice, thereby achieving controllable activation of CO2 and H2 at low temperatures. The optimal Cu–Zn3Ce2Oz catalyst achieved the CO2 conversion of 9.2%, methanol selectivity of 98.1%, and methanol STY of 311.0 g·kg–1·h–1 at 200 °C. This enhanced performance stemmed from the substitution of Ce4+ by Zn2+ and the generation of abundant Zn–Ov-Ce ensembles. These sites not only enhanced CO2 adsorption but, more crucially, served as efficient reservoirs and activation sites for spillover-derived super hydrogen from metallic Cu. A strong dependence between the catalytic activity of CO2 hydrogenation to methanol and the capability of hydrogen spillover was established, and the hydrogen spillover was suggested to be the key descriptor governing the reaction. High-pressure in situ DRIFTS experiments revealed that the spillover of active hydrogen species significantly promoted CO32– conversion to HCOO– and the following hydrogenation of HCOO– to methanol. This work establishes the targeted engineering of hydrogen spillover as a robust strategy for the rational design of high-performance catalysts tailored for efficient low-temperature CO2 utilization.