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) (M = 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.