Continuous Coupling Mechanism for High Rate Electrosynthesis of Urea on Sulfur-Coordinated Adjacent Copper Sites.

The co-electrolysis of nitrate (NO3 -) and carbon dioxide (CO2) to synthesize urea can satisfy the comprehensive needs of carbon footprint closure, waste valorization, and sustainable urea production. However, designing efficient electrocatalysts to promote the electrocatalytic C─N coupling process and achieve efficient urea production remains a challenge. Here, we design a copper (Cu)-based coordination polymer catalyst, which can achieve the dual function of promoting C─N coupling and protonation through sulfur (S)-coordinated adjacent Cu sites. Through the unique Continuous Coupling Mechanism (CCM) of low Gibbs free energy of reaction intermediates (*CO2 + *NO to *CO2NO to *ONCO2NO), the resulting catalyst achieved ultra-high Faradaic efficiency (FE) (84.9 ± 3.1%) and production rate (0.34 ± 0.012 mol h-1 g-1). Moreover, the FE and production rate of urea did not change noticeably during at least 90 cycles of testing.