Nitrogen reduction on crystalline carbon nitride supported by homonuclear bimetallic atoms

Electrocatalytic nitrogen reduction reaction (eNRR) is a new method for sustainable NH3 production, which has attracted much attention in recent years. However, the low Faradaic efficiency due to the competitive hydrogen evolution reaction (HER) and inert N≡N triple bond activation hinders its practical application. To find highly efficient electrocatalysts with excellent activity, stability and selectivity, we have studied a series of transition metal dimers (TM2) loaded on poly triazine imide, (PTI) a crystalline carbon nitride, by density functional theory calculations. The results show that most of the metal dimers have good stability. Finally, among 26 homonuclear diatomic catalysts, Mo2@PTI, Re2@PTI, and Pt2@PTI exhibit strong capability for suppressing HER, with a favorable limiting potential of -0.53, -0.36, and -0.63 V, respectively, and hence, can be used as efficient electrocatalysts for NRR. In this study, a homonuclear diatomic eNRR catalyst was designed and screened to provide not only a theoretical basis for the experiments but also an alternative approach for sustainable synthesis of ammonia.