Hybrid Catalyst Coupling Zn Single Atoms and CuN_x Clusters for Synergetic Catalytic Reduction of CO₂

Reverse water-gas shift (RWGS) reaction is the initial and necessary step of CO2 hydrogenation to high value-added products, and regulating the selectivity of CO is still a fundamental challenge. In the present study, an efficient catalyst (CuZnNx@C-N) composed by Zn single atoms and Cu clusters stabilized by nitrogen sites is reported. It contains saturated four-coordinate Zn-N-4 sites and low valence CuNx clusters. Monodisperse Zn induces the aggregation of pyridinic N to form Zn-N-4 and N-4 structures, which show strong Lewis basicity and has strong adsorption for *CO2 and *COOH intermediates, but weak adsorption for *CO, thus greatly improves the CO2 conversion and CO selectivity. The catalyst calcined at 700 degrees C exhibits the highest CO2 conversion of 43.6% under atmospheric pressure, which is 18.33 times of Cu-ZnO and close to the thermodynamic equilibrium conversion rate (49.9%) of CO2. In the catalytic process, CuNx not only adsorbs and activates H-2, but also cooperates with the adjacent Zn-N-4 and N-4 structures to jointly activate CO2 molecules and further promotes the hydrogenation of CO2. This synergistic mechanism will provide new insights for developing efficient hydrogenation catalysts.