Cu–Co/In2O3 Bimetallic Catalysts for Improved Methanol Synthesis: Synergistic Effect in CO2 Hydrogenation

In this study, Cu–Co/In2O3 bimetallic catalysts were prepared by using a deposition precipitation method. The strong hydrogen dissociation ability of Cu decreased the reduction temperature of CoO to Co, thereby promoting the formation of the Cu–Co alloy. The interaction between Cu and Co led to electron transfer from Cu to Co, which effectively inhibited the formation of the harmful Cu–In alloy and facilitated the generation of oxygen vacancies in In2O3. The presence of abundant oxygen vacancies in Cu–Co/In2O3 increased CO2 adsorption and promoted the conversion of the methanol intermediate HCOO* to CH3O*. The Cu–Co/In2O3 catalyst exhibited 10.2% conversion and 72% methanol selectivity at 300 °C and 5 MPa, which was higher than those of the monometallic catalyst Cu/In2O3 and Co/In2O3.