Clusters induced electronic delocalization of single atom sites toward efficient electrocatalytic urea synthesis from...

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 CoN₃ 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 CN coupling barriers to produce the desired urea product.