Boosting efficient C-C Coupling toward Electrocatalytic Acetate Synthesis from CO₂ via Close Cu⁺/Ag Dual Active Sites

Efficiency of C-C bond coupling in highly inert CO₂ is relatively low, which severely limits its efficient conversion to acetate. Here, we successfully developed a highly stable NF@CoMn₂O₄@Cu₂O-Ag bimetallic active site catalyst by anchoring Ag on the Cu₂O surface. In this catalyst, the Co³⁺/Mn³⁺-Mn⁴⁺ removes excess electrons from the Cu⁺ sites via strong electronic interactions, preventing the reduction of Cu₂O to metallic Cu⁰, which ensures the NF@CoMn₂O₄@Cu₂O-Ag exhibits a high resistance to deactivation. The Cu⁺ active sites of NF@CoMn₂O₄@Cu₂O-Ag efficiently electroreduce CO₂ to the *CO_atop intermediate, while the Ag active sites efficiently electroreduce CO₂ to the *CO_bridge intermediate. The proximity of Cu⁺/Ag bimetallic sites shortens the distance for C-C bond coupling between the *CO_atop and *CO_bridge intermediates, facilitating the efficient electrocatalytic coupling of CO₂ to synthesize acetate. DFT analysis indicates that the ΔG required for C-C bond coupling on the short-distance Cu⁺/Ag bimetallic sites of NF@CoMn₂O₄@Cu₂O-Ag is significantly lower than that of NF@CoMn₂O₄@Cu₂O, enabling a high Faradaic efficiency of 64.97% for acetate production at -0.3 V vs. RHE. This study provides an effective strategy for the rational design of synergistic catalysis between heterometallic catalytic sites to efficiently achieve C-C coupling for the synthesis of C₂₊ products.