Metal-free C5N2 doped with a boron atom as an efficient electrocatalyst for the nitrogen reduction reaction

Abstract

Electrochemical nitrogen reduction reactions (NRR) under ambient conditions are a promising and attractive way to ammonia (NH₃) synthesis. It is significant to develop efficient and low-cost electrocatalysts for nitrogen reduction. Herein, an investigation of single B atom doped C₅N₂ as a metal-free electrocatalyst for NRR was carried out using density functional theory (DFT) calculations. The results show that the boron atom is preferentially doped into the interstitial site of C₅N₂. The formed B-interstitial (B_int)-doped C₅N₂ sufficiently activates the nitrogen (N₂) molecule through the “acceptance–donation” process. In particular, N₂ can be effectively reduced via an alternating mechanism with a low overpotential (0.38 V). Thus, by carefully controlling the doping sites, the B-doped C₅N₂ can be an ideal candidate for an efficient NRR, which may provide a new idea in the design of NH₃ synthesis catalysts.