Defect engineered electrocatalysts for C-N coupling reactions toward urea synthesis

Urea is extensively used in agriculture and chemical industry,and it is produced on an industrial scale from CO_(2)and Haber-Bosch NH_(3)under relatively high temperature and high pressure conditions,which demands high energy input and generates masses of carbon footprint.The conversion of CO_(2)and N sources(such as NO_(2)^(−),NO_(3)^(−),and N_(2))through electrocatalytic reactions under ambient conditions is a promising alternative to realize efficient urea synthesis.Of note,the design of electrocatalyst is one of the key factors that can improve the efficiency and selectivity of C-N coupling reactions.Defect engineer-ing is an intriguing strategy for regulating the electronic structure and charge density of electrocatalysts,which endows electrocatalysts with excellent physicochemical properties and optimized adsorption en-ergy of the reaction intermediates to reduce the kinetic barriers.In this minireview,recent advances of defect engineered electrocatalysts in urea electrosynthesis from CO_(2)and various N reactants are firstly introduced.Mechanistic discussions of C-N coupling in these advances are presented,with the aim of directing future investigations on improving the urea yield.Finally,the prospects and challenges of de-fect engineered electrocatalysts for urea synthesis are discussed.This overview is expected to provide in-depth understanding of structure-reactivity relationship and shed light on future electrocatalytic C-N coupling reactions.