Computational screening of transition metal atom doped C3N as electrocatalysts for nitrogen fixation

NH3 is the main product of nitrogen reduction and is not only an indispensable fertilizer component but also a promising clean energy carrier. The electrocatalytic nitrogen reduction reaction (NRR) can reduce N2 to NH3 under ambient conditions and is one of the most promising technologies to replace the traditional Haber-Bosch process. The careful choice and design of electrocatalysts are both key to achieving an efficient electrocatalytic reaction. In this study, using density functional theory calculations, the catalytic performance of a series of 3d transition metal (TM = Cr, Mn, Fe, Co) single-atom catalysts supported on C3N (TM@C3N) was systematically investigated. The best NRR performance was achieved for the Fe-C@C3N catalyst, and the reaction follows the enzymatic mechanism. Crucially, at a limiting potential of -0.49 V, the competitive hydrogen evolution reaction was effectively inhibited. Furthermore, the electronic properties of the reaction intermediates and Fe-C@C3N were analyzed to reveal the reasons for its high activity. The results of this study will help us understand the catalytic performance of TM-atom-doped C3N and aid the design of more active C3N-based NRR catalysts.