Ambient ammonia synthesis via nitrite electroreduction over NiS2 nanoparticles-decorated TiO2 nanoribbon array

Nitrite (NO 2 − ), as a N -containing pollutant, widely exists in aqueous solution, causing a series of environmental and health problems. Electrocatalytic NO 2 − reduction is a promising and sustainable strategy to remove NO 2 − , meanwhile, producing high value-added ammonia (NH 3 ). But the NO 2 − reduction reaction (NO 2 − RR) involves complex 6-electron transfer process that requires high-efficiency electrocatalysts to accomplish NO 2 − -to-NH 3 conversion. Herein, we report NiS 2 nanoparticles decorated TiO 2 nanoribbon array on titanium mesh (NiS 2 @TiO 2 /TM) as a fantastic NO 2 − RR electrocatalyst for ambient NH 3 synthesis. When tested in NO 2 − -containing solution, NiS 2 @TiO 2 /TM achieves a satisfactory NH 3 yield of 591.9 µmol h −1 cm −2 and a high Faradaic efficiency of 92.1 %. Besides, it shows remarkable stability during 12-h electrolysis test.