Novel Design Strategy of High Activity Electrocatalysts toward Nitrogen Reduction Reaction via Boron-Transition-Metal Hybrid Double-Atom Catalysts

Electrocatalytic nitrogen reduction reaction (NRR) is a promising method for sustainable production of NH₃, which provides an alternative to the traditional Haber-Bosch process. However, the poor Faraday efficiency caused by N≡N triple bond activation and competitive hydrogen evolution reaction (HER) have seriously hindered the application of NRR. In this work, a novel strategy to promote NRR through boron-transition-metal (TM) hybrid double-atom catalysts (HDACs) has been proposed. The excellent catalytic activity of HDACs is attributed to a significant difference of valence electron distribution between boron and TMs, which could better activate N≡N bonds and promote the conversion of NH₂ to NH₃ compared with boron or metal single-atom catalysts and traditional double-atom catalysts (DACs). Hence, by means of DFT computations, the stability, activity, and selectivity of 29 HDACs are systematically investigated to evaluate their catalytic performance. B-Ti@g-CN and B-Ta@g-CN are screened as excellent nitrogen-fixing catalysts with particularly low limiting potentials of 0.13 and 0.11 V for NRR and rather high potentials of 0.54 and 0.82 V for HER, respectively. This work provides a new idea for the rational design of efficient nitrogen-fixing catalysts and could also be widely used in other catalytic reactions.