Nitrate (NO₃⁻), a nitrogen-containing pollutant, is prevalent in aqueous solutions, contributing to a range of environmental and health-related issues. The electrocatalytic reduction of NO₃⁻ holds promise as a sustainable approach to both eliminating NO₃⁻ and generating valuable ammonia (NH₃). Nevertheless, the reduction reaction of NO₃⁻ (NO₃⁻RR), involving 8-electron transfer process, is intricate, necessitating highly efficient electrocatalysts to facilitate the conversion of NO₃⁻ to NH₃. In this study, Fe-doped Co₃O₄ nanowire strutted three-dimensional (3D) pinewood-derived carbon (Fe-Co₃O₄/PC) is proposed as a high-efficiency NO₃⁻RR electrocatalyst for NH₃ production. Operating within 0.1 M NaOH containing NO₃⁻, Fe-Co₃O₄/PC demonstrates exceptional performance, obtain an impressively large NH₃ yield of 0.55 mmol·h⁻¹·cm⁻² and an exceptionally high Faradaic efficiency of 96.5% at −0.5 V, superior to its Co₃O₄/PC counterpart (0.2 mmol·h⁻¹·cm⁻², 73.3%). Furthermore, the study delves into the reaction mechanism of Fe-Co₃O₄ for NO₃⁻RR through theoretical calculations.

Sustainable mitigation of the continuously rising concentration of NO contaminants is among the most urgent issues of this century. Ambient electrocatalytic conversion of NO into useful NH₃ offers an attractive path toward achieving sustainable NO abatement and NH₃ production simultaneously. However, its efficiency is challenged by the intense competition from hydrogen evolution reaction and relatively high energy barriers of NO activation. It is thus highly desirable to explore active electrocatalyst for NO reduction reaction and investigate the mechanisms on relevant surfaces. Herein, we introduce an FeP nanorod array on carbon cloth as a high-efficiency catalyst for NO electroreduction to NH₃. In 0.2 M phosphate-buffered solution, this catalyst exhibits a low onset potential of −0.014 V. Moreover, it achieves a remarkable Faradaic efficiency of 88.49% and a large NH₃ yield of 85.62 μmol·h⁻¹·cm⁻², with durability for stable NO conversion over 12 h of electrolysis. The catalytic mechanism on FeP is investigated further by theoretical calculations.