The important role of surface charge on a new mechanism of nitrogen reduction

Abstract

The electrocatalytic nitrogen reduction reaction (NRR) is a green and sustainable approach for producing ammonia. Low-cost carbon-based materials are promising catalysts for the electrochemical NRR. Among them, Cu–N₄-graphene is a unique catalytic substrate. Its catalytic performance for the NRR has remained unclear as N₂ can only be physisorbed on such a substrate. In this work, we focus on the influence of an electronic environment on the electrocatalytic NRR. DFT computations reveal that the NN bond can be effectively activated at a surface charge density of −1.88 × 10¹⁴ e cm⁻² on Cu–N₄-graphene and further the NRR proceeds via an alternating hydrogenation pathway. This work offers a new insight into the mechanism of the electrocatalytic NRR and emphasizes the importance of environmental charges in the electrocatalytic process of the NRR.