Plasma-Electrochemical Production of Urea from Air and Flue Gas

Industrial urea synthesis is energy-intensive with high CO2 emissions, while conventional electrochemical urea synthesis is plagued by sluggish C–N coupling kinetics and low selectivity. Herein, we propose a tandem plasma-electrochemical strategy for sustainable and efficient urea synthesis using air and flue gas as abundant feedstocks, which integrates three core steps of plasma-assisted air-to-NO2– conversion, electrocatalytic reduction of flue gas-derived CO2 to HCOOH, as well as electrocatalytic coreduction of NO2– and HCOOH to urea. By rationally engineering the catalysts and optimizing the reaction parameters, we achieve an outstanding urea yield rate of 478.5 mmol h–1 g–1 and Faradaic efficiency of 75.8%. This study provides an innovative tandem pathway for urea synthesis through the direct use of industrial flue gas and atmospheric air, thus opening new horizons for green and energy-efficient production of various organonitrogen chemicals.