Unveiling the mechanism of CO2 electroreduction to C1 and C2 products on ordered double transition metal MXenes.

we use rigorous first principles simulations to comprehensively screen and explore the CO2 reduction activity of twelve different two-dimensional ordered double transition metal MXenes. Our results indicate that all the twelve MXenes show metallic characteristics and can activate CO2 significantly with strong binding energy.The electronic structure analysis reveals the charge redistribution from MXene catalysts to the antibonding states of CO2 results in strong hybridization between CO2 orbitals and surface metal orbitals. The strong CO2 binding is further affirmed by the enhanced charge transfer  from MXene to the adsorbed CO2 molecule. Simulations based on the free energy pathways show that Mo2TaC2 and Mo2TiC2 possess superior catalytic activity for conversion of CO2 to methanol and methane with very low limiting potential values of -0.35 and -0.39 V respectively where as Mo2TaC2 and Mo2VC2 were found to display excellent performance for ethanol formation with record low limiting potential of -0.32 V and -0.42 V respectively.