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

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