Stabilization of Cu Sites Within MnO for Superior Urea Electro-Synthesis.

Electrocatalytic C-N coupling between NO and CO 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 nanotube (denoted as Cu-MnO) with stable Cu-oxygen vacancies (O)-Mn dual sites is reported. Compared with pure MnO, Cu doping can effectively enhance urea production performance in the co-reduction of CO and NO . Thus, Cu-MnO catalyst exhibits a maximum Faradaic efficiency (FE) of 54.7% and the highest yield rate of 116.7 mmol h g in a flow cell. Remarkably, the urea yield rate remains over 78 mmol h g across a wide potential range. Further experimental and theoretical results elucidate the unique role of Cu-MnO solid-solution for stabilizing Cu sites in Cu-O-Mn, endowing the catalyst with superior structural and electrochemical stabilities. This thermodynamically promotes urea formation and kinetically lowers the energy barrier of C-N coupling.