Atomically Dispersed Copper Electrocatalysts with Proton‐feeding Centers for Efficient Ammonia Synthesis by Nitrate Electroreduction

Abstract Electrocatalytic conversion of nitrate pollutants into ammonia (NH ₃ ) is promising for high‐value chemical production while mitigating environmental pollution. Catalysts play a crucial role in facilitating the necessary chemical reactions, but despite substantial advancements, their efficiency and selectivity remain limited due to the high energy barriers associated with proton transfer. Herein, a unique electrocatalyst system is engineered with isolated copper sites embedded within nitrogen and oxygen co‐doped porous carbon (Cu _SA ‐NO/C). This strategically designed electrocatalyst achieves an impressive NH ₃ Faradaic efficiency of 92.7% and a yield rate of 24.9 mg h ⁻¹ mgCu ⁻¹ at a low potential of −0.2 V vs RHE, outperformed most of all previously‐reported atomically dispersed metal‐nitrogen carbon (M‐N‐C) catalysts. The catalytically active site in this electrocatalyst is identified as Cu atom coordinated with two N atoms and two O atoms (CuN ₂ O ₂ ). In situ infrared absorption spectroscopy and kinetics isotope experiments revealed that the intrinsic CuN ₂ O ₂ dramatically enhances the water dissociation process and accelerates the protonation kinetics during nitrate reduction. Furthermore, the first principles calculations show that CuN ₂ O ₂ catalytic sites also promote the adsorption of NO ₃ − and desorption of NH ₃ , along with the significantly facilitated water dissociation kinetics for proton feeding.