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

Nitrite (NO2-), as a N-containing pollutant, widely exists in aqueous solution, causing a series of environ-mental and health problems. Electrocatalytic NO2- reduction is a promising and sustainable strategy to remove NO2-, meanwhile, producing high value-added ammonia (NH3). But the NO2- reduction reaction (NO2-RR) involves complex 6-electron transfer process that requires high-efficiency electrocatalysts to accomplish NO2--to-NH3 conversion. Herein, we report NiS2 nanoparticles decorated TiO2 nanoribbon array on titanium mesh (NiS2@TiO2/TM) as a fantastic NO2-RR electrocatalyst for ambient NH3 synthesis. When tested in NO2--containing solution, NiS2@TiO2/TM achieves a satisfactory NH3 yield of 591.9 lmol h-1 cm-2 and a high Faradaic efficiency of 92.1 %. Besides, it shows remarkable stability dur-ing 12-h electrolysis test.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Nitrite (NO2-), a nitrogen-containing pollutant, is widely present in aqueous solution and causes environmental and health problems. Electro-catalytic reduction of NO2- is a promising and sustainable method to remove NO2- and produce valuable ammonia (NH3). In this study, NiS2 nanoparticles decorated TiO2 nanoribbon array on titanium mesh (NiS2@TiO2/TM) is reported as an excellent electrocatalyst for ambient NH3 synthesis through NO2- reduction reaction (NO2-RR). NiS2@TiO2/TM demonstrates a satisfactory NH3 yield of 591.9 lmol h-1 cm-2 and a high Faradaic efficiency of 92.1% when tested in NO2--containing solution. Additionally, it exhibits remarkable stability during a 12-hour electrolysis test.