Electrochemical CO₂ Reduction on Cu-Based Monatomic Alloys: A DFT Study

In recent years, single-atom alloy catalysts (SAAs) have received much attention due to the combination of structural features of both single-atom and alloy catalysts, as well as their efficient catalytic activity, high selectivity, and high stability in various chemical reactions. In this work, we designed a series of Cu-based SAAs by doping isolated 3d transition metal (TM₁) atoms on the surface of Cu(111) (TM₁ = Fe, Co, Ru, Rh, Os and Ir), in which Ir₁/Cu(111) SAAs are considered to be the most stable among 3d-series SAAs due to their optimal binding energy (E_b). The density of states of SAAs have been systematically investigated to further discuss structural properties. Based on density functional theory calculations, the activity and selectivity of Ir₁/Cu(111) SAAs are investigated for electrocatalytic CO₂ reduction reaction (CO₂RR). The initial hydrogenation of CO₂ on Ir₁/Cu(111) SAAs can form *CO intermediates, which will be further to CH₄ production by the pathway of *CO → *CHO → *CHOH → *CH₂OH → *CH₂ → *CH₃ → CH₄. This study provides theoretical insights for the rational design of selective Cu-based monatomic alloy catalysts.