CoFe alloy nanoparticles embedded in carbon nanofibers for efficient synthesis of ammonia from nitrate reduction

Abstract

Alloys can optimize the rate determining step of nitrate reduction through a synergistic effect, significantly reducing the reaction overpotential, so a series of Co_xFe_y alloy nanoparticles embedded in carbon nanofibers (CNFs) are fabricated to reduce nitrate to ammonia. Co₉Fe₁@CNFs achieve a high ammonia yield rate of 31.1 mg h⁻¹ mg_cat.^.−1 and a high faradaic efficiency (FE) of 83.5% at −0.6 V vs. RHE. In situ electrochemical tests and density functional theory (DFT) calculations reveal that the reaction follows a deoxygenation–hydrogenation pathway, where the alloyed sites lower the rate-determining step (RDS) barrier to only 0.40 eV.