Creating Frustrated Lewis Pairs in Defective Boron Carbon Nitride for Electrocatalytic Nitrogen Reduction to Ammonia

The electrocatalytic nitrogen reduction reaction (NRR) on metal-free catalysts is an attractive alternative to the industrial Haber-Bosch process. However, the state-of-the-art metal-free electrocatalysts still suffer from low Faraday efficiencies and low ammonia yields. Herein, we present a molecular design strategy to develop a defective boron carbon nitride (BCN) catalyst with the abundant unsaturated B and N atoms as Lewis acid and base sites, which upgrades the catalyst from a single "Lewis acid catalysis" to "frustrated Lewis pairs (FLPs) catalysis." ¹⁴ N₂ /¹⁵ N₂ exchange experiments and density functional theory (DFT) calculations reveal that FLPs can adsorb an N₂ molecule to form a six-membered ring intermediate, which enables the cleavage of N₂ via a pull-pull effect, thereby significantly reducing the energy barrier to -0.28 eV. Impressively, BCN achieves a high Faraday efficiency of 18.9 %, an ammonia yield of 20.9 μg h^-1  mg^-1 _cat. , and long-term durability.