Electrocatalytic C-N Coupling for Urea Synthesis.

The industrial urea synthesis consists of two consecutive processes, nitrogen + hydrogen → ammonia followed by ammonia + carbon dioxide → urea. The electrocatalytic coupling of carbon source (carbon dioxide) and nitrogen source (nitrogen, nitrite, nitrate) by skipping the ammonia synthetic process might be a promising alternative to achieve the efficient urea synthesis; in this case, two industrial steps with high energy consumption and high pollution are optimized into one renewable energy-driving electrocatalytic process. Herein, the progress of green urea synthesis is summarized, focusing on the electrocatalytic coupling of carbon source and nitrogen source for direct urea synthesis under ambient conditions. The mechanism researches for urea synthesis are also reviewed, and the future development directions of electrocatalytic urea synthesis are prospected. The electrocatalytic C-N coupling reaction realizes the efficient resource utilization and provides guidance and reference for molecular coupling reactions.