Metal-free electrocatalyst for reducing nitrogen to ammonia using a Lewis acid pair

Electrocatalytic nitrogen reduction reaction (NRR) is a promising way for the sustainable production of ammonia. However, it suffers from slow kinetics due to the difficulty of NN bond activation and the side hydrogen evolution reaction. Herein, on the basis of the concept of “Lewis acid pair”, we propose a metal-free electrocatalyst based on boron-decorated black phosphorus by using extensive first-principles calculations. In the integrated structure of the catalyst, the doped B atoms serve as Lewis acid pairs and catalytic centers, while the channels of BP provide structural advantages for hosting the pair and activating the NN bond. A new strategy of nitrogen activation based on the pull–pull effect is thus developed. Performance evaluations show that this metal-free catalyst is highly efficient for electrocatalytic nitrogen reduction with an ultra-low onset-potential of 0.19 V. This work opens a new possible avenue for nitrogen activation and can be generally applied to other two-dimensional or bulk materials.