NiWO4 nanoparticles with oxygen vacancies: high-efficiency electrosynthesis of ammonia with selective reduction of nitrite

Abstract

Electrochemical reduction of nitrite (NO2−RR) is a promising research direction for removing environmental pollutants NO2− from wastewater and generating value-added ammonia (NH3). However, NO2−RR kinetic reactivity is slow and requires high-efficient electrocatalysts. In the present study, we report C-NiWO4 nanoparticles grown on nickel foam as efficient catalysts. The NH3 yield of C-NiWO4/NF in 0.1 M NaOH containing 0.1 M NO2− was 10 974.36 μg h−1 cm−2 at −0.4 V with a Faraday efficiency of 97.6%. Notably, a Zn-NO2− battery with a C-NiWO4/NF as cathode has a high peak power density of 5.55 mW cm−2 and provides a simultaneous NH3 yield of 2194.54 μg h−1 cm−2. In addition, theoretical calculations revealed the NO2−RR mechanism of C-NiWO4/NF.