Synergistic ultra-high activity of double B doped graphyne for electrocatalytic nitrogen reduction

Double B-doping make graphyne achieve ultrahigh NRR activity. • Graphyne materials with boron doping showed enhanced catalytic activity for nitrogen reduction reaction. • Double boron doping could be efficient metal free catalysts for N 2 fixation and NH 3 synthesis. • We propose a new energy-related descriptor showing a good volcano-shaped relationship to the limiting potential. The electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is an emerging technique to address energy shortages and climate change. Thus, developing efficient but low-cost electrocatalysts is important. In the present paper, we applied γ-graphyne (γGy) doped with B, N, O, P and S as NRR catalysts, and the activities of these catalysts were studied by extensive density functional theory (DFT) calculations. Our results suggest that single N, O, P and S doping are not effective in enhancing γGy NRR activity, and the γGy with B(sp 2 )-C(sp)-B(sp) configuration has excellent overall NRR activity with a record low limiting potential (−0.12 V), good conductivity, low hydrogen evolution reaction activity and high dynamic stability. We revealed that the sp-C directly connected to active sp-B can be an energy buffer that makes a flat potential energy surface. Overall, our research provides several good NRR catalysts by carefully controlling the doping sites and provides a new strategy for further development of metal-free catalysts for the NRR.