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, 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 Faradaic 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 %. Finite-element method and density functional theory 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.
Keywords: Electrocatalytic nitrate reduction; ammonia production; finite-element method; high yield rate; tip-enhanced enrichment.
© 2024 Wiley-VCH GmbH.