An In situ Proton Filter Covalent Organic Framework Catalyst for Highly Efficient Aqueous Electrochemical Ammonia Production

The electrocatalytic nitrogen reduction reaction (NRR) driven by renewable electricity provides a green synthesis route for ammonia (NH₃) production under ambient conditions but suffers from a low conversion yield and poor Faradaic efficiency (F.E.) because of strong competition from hydrogen evolution reaction (HER) and the poor solubility of N₂ in aqueous systems. Herein, an in situ proton filter covalent organic framework catalyst ( Ru-Tta-Dfp ) is reported with inherent Ruthenium (Ru) sites where the framework controls reactant diffusion by suppressing proton supply and enhancing N₂ flux, causing highly selective and efficient catalysis. The smart catalyst design results in a remarkable ammonia production yield rate of 2.03 mg h⁻¹ mg_cat⁻¹ with an excellent F.E. of ≈52.9%. The findings are further endorsed with the help of molecular dynamics simulations and control COF systems without in situ proton filter feasibility. The results point to a paradigm shift in engineering high-performance NRR electrocatalysts for more feasible green NH₃ production.