Stabilization of Cu<sup>δ+</sup> Sites Within MnO<sub>2</sub> for Superior Urea Electro‐Synthesis
Yidong Yang, Guanzheng Wu, Jiadi Jiang, Wuyong Zhang, S. Liu, Rui Yu, Fukang Liu, Aijun Du, Lei Dai, Xin Mao, Qing Qin
Abstract
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.