Synergy of a Metallic NiCo Dimer Anchored on a C₂N–Graphene Matrix Promotes the Electrochemical CO₂ Reduction Reaction

Gaining mechanistic insights into the active site is essential to rational design of a high-performance cathode catalyst for the electrochemical CO₂ reduction reaction (CO₂ RR). Here, by means of density functional theory and computational hydrogen electrode methods, we investigated synergy of a metallic NiCo dimer anchored on a C₂N graphene matrix for promoting the CO₂ RR. It is found that heterometallic NiCo@C₂N (U_L = −0.25 V) outperforms homometallic Co₂@C₂N (U_L = −0.30 V) and Ni₂@C₂N (U_L = −0.67 V) for catalyzing the CO₂ RR toward CH₄ formation owing to its synergy within the dimer. We emphasize the impact of co-adsorbed *H, *OH, and *CO intermediates on the CO₂ RR, revealing that multiple competing reaction channels are accessible from viable co-adsorbates. Moreover, strongly-bound *H, *OH, and *CO intermediates are predicted not to deactivate metallic dimer sites for a continuous cycle of the CO₂ RR. Our study could provide a theoretical basis for optimizing a metallic dimer anchored on a N-doped graphene matrix for achieving a more advanced CO₂ RR cathode with enhanced activity and selectivity.