Hydrogenation conversion of CO2 molecules on monolayer MoS2 supported (TiO2)n clusters: A first-principles investigation

Adsorption and hydrogenation reaction of CO2 molecules on the surfaces of monolayer MoS2 supported (TiO2)n clusters were investigated using the first principles calculations. Calculation results reveal that small (TiO2)n clusters can be bounded firmly on monolayer MoS2 surface through the formation of chemical bonds between Ti and S atoms. (TiO2)n clusters on the surface of MoS2 can significantly improve the capabilities for CO2 capture. Due to the existence of dangling oxygen atoms of (TiO2)n clusters, CO2 molecules are likely to adsorb on MoS2/(TiO2)n surfaces as bent configurations. H atoms and CO2 molecules co-adsorb stably on the surfaces of MoS2/(TiO2)n, and then realize the hydrogenation conversion of adsorbed CO2 to *COOH through H adatoms migrations. The results suggest that H adatoms can migrate along several specific reaction pathways with relative lower energy barriers. Especially, for MoS2/(TiO2)4 substrate, distal H adatoms could firstly migrate to neighboring oxygen atoms with a lower energy barriers of about 1.12 eV, and further hydrogenation reaction occurs with an activation barrier of about 0.59 eV. These results may provide some useful proposals of catalyst design for hydrogenation conversion of CO2.