Hydrogenation of CO₂ to methanol utilizing the hydrogen from renewable energy sources offers a promising way to reduce CO₂ emissions through the CO₂ utilization as a carbon source. However, it is a challenge to convert CO₂ to methanol with high activity and high methanol selectivity. Herein, we report a class of metal-oxide solid-solution catalysts: M_aZrO_x (M_a = Cd, Ga), which show a methanol selectivity up to 80% with the CO₂ single pass conversion reaching 4.3%-12.4% under the reaction conditions of H₂/CO₂ = 3/1, 24※000 h^-1, 5 MPa. Structural and electronic characterizations combined with denisty functional theory calculations suggest that the M_a and Zr components in M_aZrO_x (M_a = Cd, Ga) solid-solution catalysts show a strong synergetic effect, which enhances the H₂ heterolytic dissociation and results in high activity and high methanol selectivity. The solid-solution catalyst with dual metal oxide components offers an approach for the selective hydrogenation of CO₂ to chemicals.

Although methanol synthesis via CO hydrogenation has been industrialized, CO₂ hydrogenation to methanol still confronts great obstacles of low methanol selectivity and poor stability, particularly for supported metal catalysts under industrial conditions. We report a binary metal oxide, ZnO-ZrO₂ solid solution catalyst, which can achieve methanol selectivity of up to 86 to 91% with CO₂ single-pass conversion of more than 10% under reaction conditions of 5.0 MPa, 24,000 ml/(g hour), H₂/CO₂ = 3:1 to 4:1, 320° to 315°C. Experimental and theoretical results indicate that the synergetic effect between Zn and Zr sites results in the excellent performance. The ZnO-ZrO₂ solid solution catalyst shows high stability for at least 500 hours on stream and is also resistant to sintering at higher temperatures. Moreover, no deactivation is observed in the presence of 50 ppm SO₂ or H₂S in the reaction stream.