Understanding the CO2 Reduction Selectivity toward Ethanol on Single Atom Doped Cu/Cu2O Catalysts: Insights from Bader Charge as a Descriptor

In the CO2 reduction reactions (CO2RR), the product selectivity is strongly dependent on the binding energy differences of the key intermediates. Herein, we systematically evaluated the CO2RR reaction pathways on single transition metal atom doped catalysts TM1Cu/Cu2O by density functional theory (DFT) methods and found that *CO is more likely to undergo C-O bond cleavage rather than be hydrogenated on TM1Cu/Cu2O (TM = Sc, Ti, V, Cr, Mn, Fe, Co), which facilitates C2+ production with a low-energy pathway of OC-C coupling, while it prefers to be hydrogenated to form CHO on TM1Cu/Cu2O (TM = Ni, Cu). The defects of Cu in TM1Cu/Cu2O were confirmed to enhance the production of ethanol. Furthermore, we established a scaling relationship between binding free energies of the key intermediates with the Bader charges of the active sites TM on TM1Cu/Cu2O and defective TM1Cu/Cu2O surfaces. This relationship facilitates a rational and efficient design of Cu/Cu2O-based catalysts.