Nitrogen-doped graphene encapsulating Fe2N for enhanced electrocatalytic conversion of nitrate to ammonia

Abstract

This study reports the synthesis of a nitrogen-doped graphene encapsulating iron nitride (Fe₂N@NC) electrocatalyst with outstanding activity for the NO₃RR, achieving excellent faradaic efficiency (FE) for NH₃ of 96.11% and high NH₃ yield rate of 618.35 mmol h⁻¹ g_cat⁻¹ at −0.5 V versus the reversible hydrogen electrode (RHE). Furthermore, the catalyst maintains an FE exceeding 90% across a broad range of potentials (from −0.3 to −0.7 V vs. RHE) and 85% across a wide range of concentrations (from 0.01 M to 0.5 M). Electron transfer between Fe and the support results in the formation of electron-deficient Fe. The experimental results demonstrated that electron-deficient Fe enhances the adsorption of NO₃⁻. Furthermore, doping with Fe effectively utilizes *H radicals and inhibits the hydrogen evolution reaction (HER), thereby enhancing the activity of the NO₃RR.