Bridging Electronic Structure and C─N Coupling Mechanisms in Electrochemical Urea Synthesis

Electrochemical urea synthesis (EUS) is a sustainable route for carbon-nitrogen co-utilization, offering an energy-saving alternative to the Haber-Bosch process. Recent catalyst strategies (e.g., coordination tuning, heteroatom doping, heterointerfaces) improve kinetics and selectivity by regulating active-site electronic structures to tune adsorption strength, intermediate distribution, and electronic coupling. However, there is no unified mechanistic framework that integrates multiscale electronic-structure modulation with the reaction pathways and electrochemical behaviors that govern urea formation. This review aims to bridge this gap by establishing a comprehensive framework that links electronic-structure regulation to the reaction mechanisms in EUS. We first summarize representative pathways for the co-reduction of CO2 with various nitrogen feedstocks, highlighting how adsorption configurations, binding strengths, and intermediate distributions influence electrochemical performances. We then discuss how key energy-level electronic descriptors govern adsorption strength, activation barriers, and catalytic stability. Furthermore, we examine how charge-distribution characteristics regulate interfacial interactions and dynamic reaction kinetics. Finally, we outline key challenges and opportunities for integrating theoretical predictions, operando characterization, and electronic-structure engineering to achieve efficient, selective, and scalable urea electrosynthesis. Overall, this review provides a cohesive framework that links electronic-structure design to the fundamental chemistry of EUS, offering mechanistic insights and guidance for the rational development of next-generation urea electrocatalysts.