The density functional theory calculations for the nitrogen reduction reaction show that the d-p orbital hybridization of Ru and B enhance catalytic activity with low NRR onset potential of −0.33 V and excellent competition to HER. Such improvement has mainly ascribed to the energy band regulation of non-metal to metal sites.

Abstract

Electrochemical nitrogen reduction reaction (NRR) is considered as an important strategy for ammonia using green energy. Single atom catalysts (SACs) with a metal atom as active site have been shown its advantages to high ammonia yield and low energy consumption. In this work, we proposed a new concept of SACs with the capacity of d-p orbital hybridization. These computationally designed SACs contained a metal and non-metal pair anchored on g-C₃N₄ slab. Among these SACs studied in the present work, RuB@g-C₃N₄ catalyst performed the best activity for NRR with low onset potential of −0.33 V by a two-step scanning computations using density functional theory (DFT). Moreover, suppressing effectively to the competitive hydrogen evolution reaction (HER) also make it more selective. It was further revealed that the hybridization of d-p orbitals between metal and nonmetal could regulate the electronics of active sites and facilitate the adsorption and charge transfer of adsorbed N₂ molecules resulting in enhanced catalytic performance. This work demonstrated an alternative way to further enhance the catalytic activity of SACs by introducing a non-metal atom.