Clusters induced electronic delocalization of single atom sites toward efficient electrocatalytic urea synthesis from CO₂ and N₂

Electrocatalytic conversion of CO₂ and N₂ into urea product is highly envisaged, whereas symmetrical electronic architecture of inert reactant severely prevents their adsorption and activation and further entail extremely low intrinsic activity. Herein, a novel electrocatalyst consisting of Co clusters and Co[sbnd]N₃ single-atoms dispersed on a carbon matrix is demonstrated to achieve the highest recorded urea yield rate of 20.83 mmol h⁻¹ g⁻¹ and Faradaic efficiency (FE) of 23.73 % at −0.4 V vs. RHE. Detailed investigations reveal that the concerted interplay between Co atomic clusters (Co_AC) and plane-asymmetric Co-N₃ single atom sites in CoN₃-Co_AC/NC specimen readily induced the unique electron delocalization effects and further prompted the orbital spin state of Co sites evolved from 3d⁷4s¹ to 3d⁸4s⁰, which optimized the adsorption configuration of the reactants, polarized the gas molecules through interaction with the bonding and antibonding orbitals of the optimized catalysts and eventually lowered the C[sbnd]N coupling barriers to produce the desired urea product.