Bimetallic CuAg Nanotips for Ultrahigh Yield Rate of Nitrate-to-Ammonium.

Electrochemical reduction of nitrate to ammonia (NRA) offers a sustainable approach for NH production and NO removal but suffers from low NH yield rate (<1.20 mmol h cm). We present bimetallic CuAg nanotips with tailored local environment, which achieve an ultrahigh NH yield rate of 2.36 mmol h cm at a low applied potential of -0.33 V vs. RHE, a high Faradaic efficiency (FE) of 98.8 %, and long-term operation stability at 1800 mg-N L NO , outperforming most of the recently reported catalysts. At a NO concentration as low as 15 mg-N L, it still delivers a high FE of 86.9 % and an NH selectivity of 93.8 %. Finite-element method and density functional theory calculations reveal that the CuAg exhibits reduced adsorption energy barrier of *N intermediates, favorable water dissociation for *H generation and high energy barrier for H formation, while its tip-enhanced enrichment promoting NO accumulation.