Mechanistic Insight into the Modification of the Surface Stability of In 2 O 3 Catalyst Through Metal Oxide Doping

The surface stability of In2O3 catalyst, which can be modified through the doping of metal oxide, plays vital role in methanol synthesis from CO2 hydrogenation. The surface stability of In2O3 (110) surface doped by MgO, TiO2, ZnO, Ga2O3, Y2O3, ZrO2, SnO2 and CeO2 species are studied using the density functional theory calculations in present work. Under CO atmosphere, the desorption of CO2 on the vacancy site is the rate determining step of oxygen vacancy formation on the surface of In2O3 catalyst. The calculated results demonstrate that MgO, ZnO, Ga2O3, Y2O3, SnO2 and CeO2 doped In2O3 (110) surface are favorable to be reduced via the reaction of CO with surface O atoms, which worsen the surface stability of In2O3 catalyst. Ti- and Zr-doped In2O3 (110) surfaces enhance both the reaction barriers of CO with surface O atom and adsorption of CO2 molecules on the vacancy sites. TiO2 and ZrO2 are promising modifiers to improve the activity and stability of In2O3 catalyst. The modification of the density of electron cloud or fermi level of In2O3 catalyst plays pivotal role in promotion of the stability of In2O3 catalyst. TiO2 and ZrO2 are promising modifiers to enhance the surface stability of In2O3 catalyst and the adsorption of CO2.