Selective electrosynthesis of urea via C-N coupling: Current status, challenges and future prospects

Selective electrosynthesis of urea from carbon source (CO2) and nitrogen (N-2, NO3-, NO2-) source provides a sustainable strategy for production of essential nitrogen-based fertilizers. The traditional technology of urea synthesis employs two consecutive processes, synthesis of NH3 from N-2+H-2 and urea from NH3+CO2, which always involves high energy consumption and environmental concerns. By contrast, urea electrosynthesis avoids the above harsh steps and meanwhile has higher atomic economy. Herein, we present a comprehensive review on the progress and prospect of urea electrosynthesis from abundant carbon and nitrogen sources via coupling of C-N under ambient conditions, and also discuss the mechanism researches, strategies of substrates activation, current challenges and future opportunities of urea electrosynthesis. The urea electrosynthesis via C-N coupling realizes abundant and low-cost inorganic carbon and nitrogen sources for efficient resource utilization and provides guidance and reference for C-C, C-S or other coupling reactions.