ZrO2 promoted Ru/In2O3 catalyst for selective hydrogenation of CO2 to methanol

With the strong metal-support interaction, In2O3 supported Ru catalyst has been confirmed to be active for selective hydrogenation of CO2 to methanol. Herein, we report that the addition of ZrO2 into Ru/In2O3 further improves the catalytic activity for CO2 hydrogenation to methanol. The catalyst characterization shows a formation of In2O3-ZrO2 solid solution, which is an excellent support for the highly dispersed Ru catalyst. Compared to Ru/In2O3, a significantly higher methanol selectivity is achieved over the Ru/In2O3-ZrO2 catalyst with 1 wt% Ru loading. The methanol space–time yield (STY) reaches 0.685 gMeOH h−1 gcat−1 at 300 ℃, 5 MPa, and 21000 cm3 gcat−1h−1. It has more than 20% increase compared to Ru/In2O3. The addition of ZrO2 optimizes the oxygen vacancies of In2O3, improves the CO2 adsorption and enables a more stable catalyst architecture, while the hydrogen spillover by the highly dispersed ruthenium improves the hydrogen activation ability of the catalyst. All these results in a high level of methanol yield.