Self-supported P-doped NiFe2O4 micro-sheet arrays for the efficient conversion of nitrite to ammonia

Abstract

The nitrite reduction reaction (NO2−RR) is an important process for eliminating toxic nitrites from water while simultaneously producing high-value ammonia under ambient conditions. For the aim to improve the NO2−RR efficiency, we designed a new synthetic strategy to prepare a phosphorus-doped three-dimensional NiFe2O4 catalyst loaded onto a nickel foam in-situ and evaluated its performance for the reduction of NO2− to NH3. The catalyst achieved a high Faradaic efficiency (FE) of 95.39%, and an ammonia (NH3) yield rate of 34788.51 µg h−1 cm−2 at − 0.45 V vs. RHE. A high NH3 yield rate and FE were maintained after 16 cycles at − 0.35 V vs. RHE in an alkaline electrolyte. This study provides a new direction for the rational design of highly stable electrocatalysts for the conversion of NO2− to NH3.