Indium oxide supported nickel catalyst has been experimentally confirmed to be highly active for CO2 hydrogenation towards methanol.In this work,the reaction mechanism for CO2 hydrogenation to metha-nol has been investigated on a model Ni/In2O3 catalyst,i.e.,Ni4/In2O3,via the density functional theory(DFT) study.Three possible reaction pathways,i.e.,the formate pathway,CO hydrogenation and the reverse water-gas-shift (RWGS) pathways,have been examined on this model catalyst.It has been demonstrated that the RWGS pathway is the most theoretically-favored for CO2 hydrogenation to metha-nol.The complete RWGS pathway follows CO2 + 6H → COOH + 5H → CO + H2O + 4H → HCO + H2O +3H → H2CO + H2O + 2H → H3CO + H2O + H → H3COH + H2O.Furthermore,it has been also proved that the interfacial oxygen vacancy can serve as the active site for boosting the CO2 adsorption and charge transfer between the nickel species and indium oxide,which synergistically promotes the consecutive CO2 hydrogenation towards methanol.