Enhancing the yield of electrocatalytic C–N coupling for urea synthesis: challenges, strategies, and prospects

Abstract

Electrocatalytic C–N coupling-driven urea synthesis powered by renewable energy offers a green pathway toward achieving carbon neutrality and closed-loop nitrogen cycling. Compared with the traditional high-energy-consuming, two-step Haber–Bosch–Meiser process, the electrocatalytic approach enables direct urea synthesis at ambient temperature and pressure, significantly reducing energy consumption and carbon emissions. However, this process remains constrained by challenges such as the difficulty of NN activation, mismatched coverage of C–N intermediates, and product trapping and secondary conversion, resulting in low urea yield and selectivity. This paper systematically reviews recent research advances in enhancing the yield of electrocatalytically synthesized urea, organized around the main themes of “adsorption and activation”, “pathway and intermediate regulation”, “dual-function synergy”, and “product desorption”. First, regarding reactant adsorption and activation: for the N₂ + CO₂ system, strategies for NN bond activation and interfacial electronic structure regulation are summarized; and for the NO₃⁻ + CO₂ system, the thermodynamic advantages of nitrate substitution pathways and methods for optimizing active sites are elaborated. Second, regarding pathway and intermediate regulation, approaches such as pathway trimming, defect/vacancy engineering, selective control of key intermediates, and liquid carbon source utilization are introduced for N₂ + CO₂, NO₃⁻ + CO₂, and HCOOH + NO₃⁻ systems. Third, in the section on bifunctional synergy, representative cases involving N₂ with CO₂, and NO₃⁻ with CO₂ demonstrate how site specialization, interfacial polarization, and operational parameter tuning can spatially and temporally align reactant supply with intermediate coupling windows, thereby achieving dual enhancements in selectivity and yield. Finally, in the product desorption segment, effective methods are summarized for reducing urea-surface binding energy while maintaining active site regenerability through interfacial electronic structure design, electrolyte regulation, and multiphase interface construction. Overall, this paper systematically summarizes multidimensional strategies for enhancing urea electrocatalytic synthesis yield across diverse reactant systems, while identifying current challenges in mechanism elucidation, stability, and scale-up. Crucially, electrocatalytic urea synthesis demonstrates yield potential surpassing traditional thermal catalysis, offering a cleaner, more sustainable alternative pathway for urea production.