Theoretical study on the reaction mechanism of CO2 hydrogenation to methanol

Hydrogenation of CO2 is challenging from both economic and environmental view points. In the present study, density functional theory (DFT) method was employed to investigate the reaction mechanism of methanol synthesis from CO2 hydrogenation. Two possible reaction pathways were proposed, where hydrogenation of CO2 led to intermediate HOCO free radical, followed by the formation of intermediate HCOOH or CO, finally resulting in the methanol formation. The results showed that the preferred pathway was CO2 → CO → H2CO → CH3OH, whose enthalpy energy is −35.389788 kJ/mol. The calculated results of the configuration and the enthalpy energy of classic molecules were in good agreement with the values in literature, which indicated that the results should be reliable.