Mechanistic insights in electrochemical C–N coupling reactions to urea

• Systematically reveals the fundamental mechanisms of electrochemical C-N coupling, with a focus on the dominant pathways for CO 2 /nitrate and CO 2 /N 2 reactions. • Identifies key reactive intermediates (e.g., *CO, *NH 2 , *NO 2, *NO) governing selectivity and efficiency through integrated experimental and theoretical analysis. • Clarifies how catalyst microstructure steers reaction outcomes by modulating intermediate binding and conversion, providing a rationale for catalyst design. Electrochemical C–N coupling has emerged as a transformative approach for converting carbon dioxide (CO 2 ) and nitrate pollutants or atmospheric nitrogen (N 2 ) into high-value compounds such as urea, thus simultaneously mitigating environmental impacts and enabling resource recovery. To bridge fundamental insights to practical applications and guide the rational design of catalysts, a clear mechanistic understanding of electrochemical C–N coupling reactions is crucial. However, despite recent advances, a comprehensive understanding of the atomistic reaction pathways remains underdeveloped. This review focuses on elucidating the fundamental mechanisms governing C–N bond formation, with an emphasis on dominant pathways for CO 2 /nitrate and CO 2 /N 2 coupling reactions. Through analysis of experimental and theoretical case studies, we identified the key reactive intermediates (*CO, *NH 2 , *NO 2 , *NO, *N 2 ) during the reaction process. Special attention is given to the role of catalyst microstructure to steer the reaction selectivity and efficiency via the change in key intermediate. This review provides a systematic overview of C–N coupling mechanisms by reconciling experimental evidence with theoretical descriptors, addressing a critical gap in the field.