Boosting Synergistic Catalysis C–N Coupling via Stabilizing Close Zn/Ti Bimetallic Sites for Electrocatalytic Urea Synthesis from CO2 and Nitrite

Electrocatalytic urea synthesis is significantly limited by the low efficiency of C–N bond coupling between CO2 and nitrite. Here, we designed a Zn and Ti bimetallic active site catalyst by anchoring TiO2 on the surface of ZnO and developed a new NF@CoMn2O4@ZnO-TiO2 electrocatalyst with high resistance to deactivation. The Co3+/Mn3+-Mn4+ solid oxide pairs in NF@CoMn2O4@ZnO-TiO2 maintain their high stability by extracting accumulated electrons around Zn2+ and Ti4+ through strong electronic interactions. The Zn active sites on NF@CoMn2O4@ZnO-TiO2 can efficiently catalyze the reduction of CO2 to *CO, while the Ti active sites can efficiently catalyze the reduction of NO2– to the *NH2 intermediate product. The proximity of the Zn and Ti sites shortens the coupling distance between the *CO and *NH2 intermediates, facilitating the efficient electrocatalytic synthesis of urea. DFT calculations indicate that the ΔG required for the coupling of *CO and *NH2 adsorbed on short-range Zn and Ti sites on CoMn2O4@ZnO-TiO2 is lower compared to CoMn2O4@ZnO and ZnO. This results in a remarkably high Faradaic efficiency of 61.18% for urea synthesis at −0.6 V vs RHE for NF@CoMn2O4@ZnO-TiO2. This work provides a new pathway for achieving synergistic catalysis of C–N coupling reactions between different metal catalytic sites.