Density functional theory study of CO2 reduction to CH3OH on the surfaces of metal (Cu, Ni, and Mn)-doped carbon nanotubes

The reduction reaction of carbon dioxide (RR-CO2) to CH3OH using metal catalysts can reduce the energy required by this process. In this study, we investigated the RR-CO2 mechanisms with Cu-, Ni-, and Mn-doped carbon nanotubes (CNTs). The substitutional (doping with carbon atom) positions in CNTs are suitable sites for adsorbing Cu, Ni, and Mn metals. The reaction paths to the RR-CO2 were investigated in the gas and solvent phases. The results demonstrated that the overpotential values with Cu-, Ni-, and Mn-doped CNT(8, 0) and CNT(6, 6) catalysts in the gas and solvent phases were lower than that obtained with metal catalysts in previous studies (−1.116 V). Thus, metal-doped CNT(8, 0) and CNT(6, 6) catalysts with low overpotentials could be applied in the RR-CO2.