Interface-engineered inverse ZnO/Cu for low-temperature CO2 hydrogenation to methanol

•Highly porous CuO with specific surface area up to 120 m2/g is prepared as intermediate to produce porous Cu substance.•Nearly 8.3 % CO2 conversion and above 99% methanol selectivity is achieved in the 50 wt.% ZnO/Cu inverse catalyst.•The STY of methanol presents a particular volcanic curve related to Cu-ZnO interface.•ZnO vacancy concentration formed by Cu-ZnO SMSI greatly affects the selectivity of CO2 hydrogenation into methanol. Herein, via a mechanical-assisted NaCl template method, inverse ZnO/Cu catalysts with controllable ZnO loading weights from 5 to 100 wt% are successfully designed. During CO2 hydrogenation, we find that the space–time yield (STY) of methanol is greatly affected by the ZnO loading weights, and presents a particular volcanic curve related to the nominal loading weights of ZnO. The data of HRTEM and EDS mappings reveals the formation of ZnO-Cu strong metal-supporting interaction (SMSI) after H2 reduction. Meanwhile, the chemistry probe studies discover that the concentration of surface-adsorbed CO2 and H2 depended on the ZnO loading weight. On these grounds, the 50% ZnO loading weight is suggested as the optimized value, where both the surface-adsorbed CO2 and H2 species reached equilibrium. In addition, we also observe that the oxygen vacancy concentration of ZnO fluctuated with the reaction temperatures by Quasi-In-situ XPS, further leading to a change in the CO2 hydrogenation reaction path.