Recent Progress in Electrocatalytic Urea Synthesis under Ambient Conditions

Industrial urea synthesis is performed under harsh conditions requiring huge energy consumption and accompanied by heavy environmental pollution. Electrocatalytic C–N coupling for valuable urea synthesis from the coreduction of CO2 and an inexpensive nitrogen source, such as N2, nitrite, nitrate, and NO, under ambient conditions is a potential green and sustainable substitute for the harsh industrial process. However, the nuts and bolts of electrocatalytic urea synthesis are seldom systemically reviewed. In this Perspective, theoretical and experimental research progress toward urea electrosynthesis is introduced and critically highlighted. From the view of the reaction pathway for the generation of urea molecules, chemiadsorption and activation of inert molecules (CO2 or N2) and the subsequent C–N couplings are the most important steps to determine the efficiency and selectivity of electrocatalytic reactions. The mechanisms of C–N coupling and hydrogenation toward urea formation in the above progress are summarized and rigorously estimated. This perspective reviews the exploration and preparation of electrocatalysts for urea synthesis with high efficiency and selectivity.