Design of C3N-based single-atom catalysts and calculation of the performance in electrocatalytic NO reduction reaction

Abstract Electrocatalytic reduction of NO to NH₃ is driven by renewable electricity to produce NH₃ with chemical value-added. The entire process is environmentally friendly and green, and it is a method for reducing NO emissions with broad research prospects. Therefore, it is extremely urgent to develop electrocatalysts with high activity, selectivity and stability. In this study, density functional theory calculations were used to investigate the catalytic activity of 3d transition metal atoms doped with C and N vacancies on the surface of C₃N to form single-atom catalysts (TM-C@C₃N and TM-N@C₃N). Through the analysis of the thermodynamic stability of the catalyst, the adsorption capacity of NO, the free energy barriers of the first and final hydrogenation reactions, and the inhibition of hydrogen evolution reaction, it was determined that V-C@C₃N and V-N@C₃N have the potential to be highly active electrocatalysts. Meanwhile, the entire pathway simulation calculation showed that the limiting potentials of the NORR process on V-C@C₃N and V-N@C₃N were –0.450 V and –0.386 V, respectively, demonstrating excellent catalytic activity. In addition, the reason for the high activity was understood through the analysis of the electronic properties of the potential-determining step. Therefore, the catalyst proposed in this study is expected to directly convert the air pollutant NO into valuable NH₃.