Electrochemical nitrite (NO2–) reduction can yield value-added ammonia (NH3) while remove NO2– as enviromental pollutant in wastewater; however, it involves six-electron transfer process and requires highly efficient and selective electrocatalysts....

Electrocatalytic reduction of nitrite (NO 2 − ) is of vital significance for the removal of NO 2 − pollution and simultaneously making value-added ammonia (NH 3 ). Herein, Ni nanoparticles anchored on the TiO 2 nanoribbon array with the Schottky junction were successfully constructed for highly selective NO 2 − reduction to NH 3 . Density functional theory reveals the construction of the Ni@TiO 2 Schottky junction leads to charge rearrangement and optimized adsorptive energy of intermediates, assuring the selective conversion from NO 2 − to NH 3 . Expectantly, this catalyst achieves an impressive NH 3 yield of 568.7 μmol h −1 cm −2 and an ultrahigh Faradaic efficiency of 98.5% under ambient conditions with good stability.

Electrochemical nitrate (NO3 –) reduction is a potential approach to produce high-value ammonia (NH3) while removing NO3 – pollution, but it requires electrocatalysts with high efficiency and selectivity. Herein, we report the development of Fe3O4 nanoparticles decorated TiO2 nanoribbon array on titanium plate (Fe3O4@TiO2/TP) as an efficient electrocatalyst for NO3 –-to-NH3 conversion. When operated in 0.1 M phosphate-buffered saline and 0.1 M NO3 –, such Fe3O4@TiO2/TP achieves a prominent NH3 yield of 12394.3 μg h–1 cm–2 and a high Faradaic efficiency of 88.4%. In addition, it exhibits excellent stability during long-time electrolysis.