New insight on electroreduction of nitrate to ammonia driven by oxygen vacancies-induced strong interface interactions

• Oxygen vacancies are used to assist the synthesis of Ag/Cu 2 O hybrids. • High performance for NH 3 synthesis derives from the strong interface interaction. • The interface interaction boosts the adsorption of NO 3 − and the formation of *N. Ammonia (NH 3 ) synthesis from electrochemical conversion of nitrate (NO 3 − ) can efficiently reduce the emission of nitrogen oxide. However, the complex reaction pathways of nitrate reduction to NH 3 are not fully revealed by previous reports. Here we point out that Ag/Cu 2 O hybrids prepared with the assistance of oxygen vacancies (O V ) have very competitive activity (selectivity: 96.85%, Faradaic efficiency: 96.45%) for NH 3 synthesis from NO 3 − . Detailed characterizations demonstrate that this high performance of Ag/Cu 2 O hybrids derives from the strong interface interactions owing to the formation of strong Ag Cu bonds. Both online differential electrochemical mass spectrometry (DEMS) and density functional theory (DFT) calculations demonstrate that the strong interface interactions between Ag nanoparticles (NPs) and Cu 2 O can efficiently boost the adsorption of NO 3 − and facilitate the formation of *N intermediates in NH 3 synthesis.