Modulating *CO Adsorption Behavior: A Mechanistic Strategy for High‐Efficiency C–N Coupling in Urea Electrochemical Synthesis

Abstract

ABSTRACT Electrochemical urea synthesis through CO 2 and nitrate/nitrite (NO 3 − /NO 2 − ) co‐reduction represents a revolutionary alternative pathway for urea formation. Although studies reveal that restraining C‐intermediates desorption is beneficial for C‐N coupling, *CO adsorption behaviors were usually described by *CO binding energy based on DFT calculations. The intrinsic reason why the *CO adsorption behaviors could modulate the activity for urea formation remains ambiguous. Herein, a series of high‐density Cu 1 /M 1 ‐NOC electrocatalysts regarding single‐atomically dispersed Cu 1 /Cu 1 , Cu 1 /Ni 1 , Cu 1 /Au 1 , or Cu 1 /Pd 1 sites anchored on N, O‐co‐doped carbon were developed for electrochemical urea synthesis. In situ spectroscopy reveals that strengthening *CO binding energy not only enhances *CO coverage but also increases the proportion of linear *CO absorption configuration (*CO L ). The *CO L with sp hybridization exhibits stronger electrophilicity than that for bridge adsorption, thereby favoring coupling with N‐intermediates. Notably, a linear relationship was established by plotting urea yield versus *CO L coverage. As such, the intrinsic reason for facilitating C─N coupling was originated from the local enrichment of *CO L . The optimal Cu 1 /Pd 1 ‐NOC catalyst exhibits the high urea Faradaic efficiencies of 73.73% and 67.3% with NO 2 − and NO 3 − as N source, respectively. This research provides an effective strategy to boost urea performance by precisely controlling the *CO adsorption behaviors.