Electrochemical CO2 Reduction Reaction on M@Cu(211) Bimetallic Single-Atom Surface Alloys: Mechanism, Kinetics, and Catalyst Screening

Copper is a well-known metal for catalyzing the electrochemical CO2 reduction reaction (CO2 RR) toward valuable hydrocarbons and alcohols. Here, using a combined density functional theory and microkinetic modeling approach, we systematically investigated 11 bimetallic M@Cu(211) single-atom stepped surface alloys for their CO2 RR activity. It is revealed that the stepped M edge is most likely to be the active site for CO2 RR. The primary reaction pathway is identified as *COOH → *CO → *CHO with the potential-determining step of *CO + H+ + e– → *CHO, leading to either CH4 or CH3OH formation at more negative potential. Especially, Ru@Cu(211) and Fe@Cu(211) are both predicted to be most efficient in promoting CO2 RR toward CH4 owing to their breaking of the coupled scaling relations of key intermediates' binding at the active site. Furthermore, the binding strength of *CO and *OH can be used as a good descriptor for differentiating various M@Cu(211) for CO2 RR activity and selectivity, and specifically, the moderate oxophilic and carbophilic elements of M are preferred. Our study highlights the utmost importance of breaking the linear scaling relations of key intermediates' binding at the active site for boosting CO2 RR performance.