Recent Advances in Microenvironment Engineering for Selective Electrochemical C-N Coupling.

Electrochemical C-N coupling via the coreduction of CO₂ and nitrogenous species (N₂/NO_x) presents a sustainable route to synthesize value-added C-N compounds under mild conditions. However, competing pathways and mismatched intermediate kinetics hinder the selective formation of products like urea, amines, and amides. Recent advances reveal that rational modulation of the electrochemical microenvironment can effectively steer reaction pathways and stabilize coupling-relevant intermediates. This review systematically summarizes how microenvironment engineering, originally developed for CO₂ and NO_x reduction reactions, can be leveraged to enhance C-N coupling efficiency and selectivity. The key strategies are categorized into 1) catalyst-centered design (e.g., ligand coordination, defect engineering, and morphology control), 2) ionic and electrolyte modifications (e.g., cation/pH effects), and 3) dynamic approaches such as pulsed electrolysis. These methods shape local fields, surface coverage, and mass transport properties, ultimately directing reactants toward cross-coupling over competing routes. By drawing parallels with well-established CO₂RR/NO_xRR systems and showcasing emerging examples in C-N coupling, the central role of microenvironment control is highlighted. Finally, a perspectives on strategies to further improve activity, selectivity, and atom economy in future C-N coupling systems are offered.