Strain and Ligand Effects on CO2 Reduction Reactions over Cu-Metal Heterostructure Catalysts

The strain and ligand effects on the adsorption energies of key intermediates (*COOH, *CO, *CHO, and *COH) in CO2 reduction reactions on the Cu-M(111) (M = Ni, Co, Cu, Rh, Ir, Pd, Pt) heterolayered catalysts have been quantitatively separated using first-principles calculations. Contrary to the common belief that strain is always the leading factor influencing catalytic performance of the core-shell type heterostructure catalysts, the ligand effect due to the underlying hetero elements should not be ignored and may become dominant for strain-insensitive adsorbates (*CO and *COH). Moreover, the models of Cu(2 ML/3 ML)-M(111) = Ir, Rh, Pt, Pd) have been shown to be better catalysts for CO2 reduction, as they require lower overpotential to drive the reaction than the Cu(111) slab. Particularly, the overpotential is predicted to be lowered by 0.17 V for Cu(3 ML)-Ir(111) model catalyst. Thus, both effects should be considered in heterostructure catalyst design.