Nb-doped NiO nanoflowers for nitrite electroreduction to ammonia

Electrocatalytic reduction of nitrite to ammonia (NO 2 RR) 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 NO 2 RR catalyst, which exhibits the highest NH 3 -Faradaic efficiency of 92.4% with an NH 3 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 NO 2 - activation, decreased protonation energy barriers, and restricted hydrogen evolution, ultimately leading to a high NO 2 RR selectivity and activity.