Stabilization of Cuδ+ Sites Within MnO2 for Superior Urea Electro‐Synthesis

Abstract Electrocatalytic C‐N coupling between NO 3 ‐ and CO 2 has emerged as a sustainable route for urea production. However, identifying catalytic active sites and designing efficient electrocatalysts remain significant challenges. Herein, the synthesis of Cu‐doped MnO 2 nanotube (denoted as Cu‐MnO 2 ) with stable Cu δ+ ‐oxygen vacancies (O vs )‐Mn 3+ dual sites is reported. Compared with pure MnO 2 , Cu δ+ doping can effectively enhance urea production performance in the co‐reduction of CO 2 and NO 3 ‐ . Thus, Cu‐MnO 2 catalyst exhibits a maximum Faradaic efficiency (FE) of 54.7% and the highest yield rate of 116.7 mmol h −1 g cat. −1 in a flow cell. Remarkably, the urea yield rate remains over 78 mmol h −1 g cat. −1 across a wide potential range. Further experimental and theoretical results elucidate the unique role of Cu‐MnO 2 solid‐solution for stabilizing Cu δ+ sites in Cu δ+ ‐O vs ‐Mn 3+ , endowing the catalyst with superior structural and electrochemical stabilities. This thermodynamically promotes urea formation and kinetically lowers the energy barrier of C‐N coupling.