Abstract
Electrochemical C - N coupling is an appealing approach for sustainable urea synthesis, while it is technically challenging due to the complex reaction mechanism and the spatiotemporal mismatch between C- and N- intermediates. Here, inspired by click chemistry, we design a hierarchical click-site catalyst (Se-InO(x)) that enables an efficient sequential-chain coupling pathway for urea electrosynthesis, achieving a urea yield rate of 254.94 mmol h(-1) g(-1), Faradaic efficiency of 78.61%, >85% N(urea)-selectivity and 100% C(urea)-selectivity. Mechanistic studies reveal that Se-InO(x) as the first click-site can selectively adsorb NO(3)(-) and hydrogenate it to stable *NO(2), while inhibiting CO(2) adsorption at this stage. The surface-anchored *NO(2) then acts as the second click-site to click couple with CO(2), forming the key *CO(2)NO(2) intermediate. This sequential-chain coupling strategy effectively resolves the spatiotemporal mismatch between N- and C- intermediates, thereby maximizing the suppression of side-reactions and enhancing C - N coupling selectivity. Techno-economic analysis and scalable synthesis validate the feasibility of this approach, providing a blueprint for high-selectivity multicomponent electrosynthesis.