Bimetallic Cu11Ag3 Nanotips for Ultrahigh Yield Rate of Nitrate‐to‐Ammonium

Electrochemical reduction of nitrate to ammonia (NRA) offers a sustainable approach for NH3 production and NO3‐ removal but suffers from low NH3 yield rate (<1.20 mmol h‐1 cm‐2). We present bimetallic Cu11Ag3 nanotips with tailored local environment and tip‐enhanced effects, which achieve an ultrahigh NH3 yield rate of 2.36 mmol h‐1 cm‐2 at a low applied potential of ‐0.33 V vs. RHE, a high Faradic efficiency (FE) of 98.8%, and long‐term operation stability at 1800 mg‐N L‐1 NO3‐, outperforming most of the recently reported catalysts. At a NO3‐ concentration as low as 15 mg‐N L‐1, it still delivers a high FE of 86.9% and an NH3 selectivity of 93.8%. Operando ATR‐FTIR spectra, finite‐element method, and DFT calculations reveal that the Cu11Ag3 exhibits reduced adsorption energy barrier of *N intermediates, favorable water dissociation for *H generation and high energy barrier for H2 formation, while its tip‐enhanced enrichment promoting NO3‐ accumulation.