Charge Polarization Boosting Electrochemical Urea Synthesis by Co‐Reduction of CO2 and Nitrite in Dilute Concentrations with a Unity Carbon Selectivity

Abstract Synthesis of urea through electrocatalytic coupling reaction of CO 2 with nitrite (NO 2 − ) represents a sustainable means to substitute the conventional energy‐intensive urea synthetic protocol. The direct conversion of dilute NO 2 − in real wastewaters to urea with high efficiency is still a significant challenge, as C‐intermediates tend to go through an extensive reduction achieving mostly C‐containing productions due to the lack of N‐intermediates, originating from slow diffusion rate of NO 2 − . Herein, we report the charge‐polarized Fe δ− ‐Cu δ+ dual sites in metal/carbon heterojunction material (Cu@Fe−N−C) for co‐reduction of CO 2 and dilute NO 2 − solution (100 ppm NO 2 − ‐N). The electron‐rich single Fe atoms dispersed N‐doped carbon (Fe−N−C) restrain *CO desorption, and the electron‐deficient Cu nanoparticles (Cu) promote the deep reduction of NO 2 − to *NH 2 . As a result, the obtained Cu@Fe−N−C exhibits a high Faradaic efficiency for urea of 50.05 % with a yield of 850.57 mg h −1 g −1 at −0.35 V ( vs . RHE) in a flow cell. Moreover, C urea‐selectivity reaches to 100 % and a near‐unity selectivity for the value‐added urea and NH 3 is realized. The present results provide a valuable reference for the design of new catalysts for efficient synthesis of C−N compounds in dilute NO 2 − solution.