Fundamentals and Rational Design of Heterogeneous C-N Coupling Electrocatalysts for Urea Synthesis at Ambient Conditions

Electrocatalytic C-N coupling reaction is regarded as a promising strategy for achieving clean and sustainable urea production by coreducing CO2 and nitrogen species, thus contributing to carbon neutrality and the artificial nitrogen cycle. However, restricted by the sluggish adsorption of reactants, competitive side reactions, and multistep reaction pathways, the electrochemical urea production suffers from a low urea yield rate and low selectivity so far. In order to comprehensively improve urea synthesis performance, it is crucial to develop highly efficient catalysts for electrochemical C-N coupling. In this article, the catalyst-designing strategies, C-N coupling mechanisms, and fundamental research methods are reviewed. For the coreduction of CO2 and different nitrogen species, several prevailing reaction mechanisms are discussed. With the aim of establishing the standard research system, the fundamentals of electrocatalytic urea synthesis research are introduced. The most important catalyst-designing strategies for boosting the electrocatalytic urea production are discussed, including heteroatom doping, vacancy engineering, crystal facet regulation, atom-scale modulation, alloying and heterostructure construction. Finally, the challenges and perspectives are proposed for future industrial applications of electrochemical urea production by C-N coupling. The rational design of efficient heterogeneous electrocatalysts is crucial but still very challenging for sustainable urea production at ambient conditions by coreducing CO2 and nitrogen species. In this review article, design strategies for C-N coupling electrocatalysts are emphasized-for the in-depth understanding of the structure-activity relationship and the establishment of a systematic research framework -toward this emerging field. image