Bimetal-Doped Boron Nitride Electrocatalyst for Nitrogen Reduction Reaction: A Theoretical Design

The electrocatalytic nitrogen reduction reaction (NRR) is a green, low-energy alternative to the Haber-Bosch process. This study constructed dual unsaturated vacancies on a stable B₄N₄ monolayer and designed a B₃N₄ substrate. The calculation shows that the B₃N₄ structure has a great stability. The dual atom catalysts (DACs) were constructed through bimetallic doping, denoted as TM₁TM₂@B₃N₄, for the NRR using a theoretical high-throughput screening integrated with density functional theory (DFT) calculations. The electrocatalytic NRR performance of the 91 designed DACs was systematically investigated. 4 heteronuclear systems CrZr@B₃N₄, CrHf@B₃N₄, MnNb@B₃N₄, and FeMo@B₃N₄ were screened out, which are promising NRR electrocatalysts with excellent NRR activities and selectivities using a 3+1 screening strategy. Notably, the designed CrZr@B₃N₄ demonstrates an outstanding performance with a low limiting potential of -0.16 V along the mixed pathway. Furthermore, a Cascading Associative-Dissociative (Cascading A-D) reaction mechanism is proposed in which N─N bond scission takes place immediately after the second proton-coupled electron transfer step (^*N₂H + H⁺ + e^- → ^*NH^*NH). This reaction mechanism was only observed in eight designed electrocatalysts with relatively low activities. This work provides a rational framework for designing high-performance NRR catalysts and efficient ammonia synthesis.