Theoretical study of electrocatalytic urea synthesis through CO2 and N2 on metal cluster decorated C2N

The electrocatalytic C–N bond coupling of N2 and CO2 for urea production is an energy-efficient and eco-friendly alternative in industry. However, the remarkable stability of the inert gases and potential competing reduction reactions in electrocatalytic processes lead to low activity and selectivity. So, searching for low-cost electrocatalysts with high activity and selectivity for urea formation is very vital. Herein, by density functional theory calculations, we have systematically studied the process of electrocatalytic N2 and CO2 coupling for urea production on monolayer C2N matrix containing chromium transition metal clusters (Cr3@C2N). Our calculational results reveal that N2 and CO2 can be chemically adsorbed and activated on Cr3@C2N and the formation of *NCON intermediate that is a key precursor for urea generation is exothermic. The limiting potential of urea formation is − 0.72 V. Meanwhile, the competing reactions, such as nitrogen reduction reaction and hydrogen evolution reaction have also been considered, which demonstrate the reaction of urea formation is predominant. To sum up, the Cr3@C2N possesses high activity and selectivity toward the electrosynthesis of urea, providing a new ideal for designing catalysts for C–N coupling electrochemical reactions. CO2 and N2 can be convert into urea on the electrocatalyst Cr3@C2N (transition metal cluster doped C2N) with high activity and selectivity.