Exploring the synergistic effect of B–N doped defective graphdiyne for N2 fixation†
Abstract
The electrochemical nitrogen reduction reaction (NRR) is currently the most attractive method for ammonia production, in which the development of high efficiency and low-cost electrocatalysts is still a challenge. A lot of recent research has been focused on B single-atom catalysts. However, doping carbon materials with multiple hetero-elements has been rarely explored. Herein, we investigate the catalytic performance of B doped, N doped, and BN co-doped defective graphdiyne (B@GDY, N@GDY and BN@GDY) for nitrogen reduction by using density functional theory. Our results reveal that BN@GDY exhibits higher catalytic efficiency relative to that of single B doping, which is manifested by a significant decrease in overpotential (0.32 V vs. 0.61 V) via the enzymatic mechanism. The projected density of states and Bader charge analysis indicate that BN@GDY can promote the charge transfer from the catalytic substrate to adsorbed N2, in which the addition of N can convert B from sp2 to sp3 hybridization. Meanwhile, the competing hydrogen evolution reaction (HER) can be well inhibited during the NRR for both B/BN@GDY substrates, especially in BN@GDY, indicating the high selectivity of BN@GDY towards the NRR. Above all, this work puts forward a novel metal-free electrocatalyst for the NRR and may provide useful guidance for the design of new non-metal nitrogen reduction electrocatalysts.