Nb-doped NiO nanoflowers for nitrite electroreduction to ammonia

Electrocatalytic reduction of nitrite to ammonia (NO2RR) is considered as an appealing route to simultaneously achieve sustainable ammonia production and abate hazardous nitrite pollution. Herein, atomically Nb-doped NiO nanoflowers are designed as a high-performance NO2RR catalyst, which exhibits the highest NH3-Faradaic efficiency of 92.4% with an NH3 yield rate of 200.5 μmol h-1 cm-2 at -0.6 V RHE. Theoretical calculations unravel that Nb dopants can act as Lewis acid sites to render effective NO2- activation, decreased protonation energy barriers, and restricted hydrogen evolution, ultimately leading to a high NO2RR selectivity and activity.