Fe-doped Co₃O₄ nanowire strutted 3D pinewood-derived carbon: A highly selective electrocatalyst for ammonia production via nitrate reduction

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.