A MOF-derived Fe–Cu@NC electrocatalyst for efficient conversion of nitrate into ammonia

Abstract

Electrochemical nitrate reduction provides an efficient strategy for converting nitrate pollutants into value-added ammonia, simultaneously addressing environmental and energy challenges. In this work, a bimetallic Fe–Cu@NC catalyst was synthesized by high-temperature pyrolysis, yielding bamboo-like N-doped carbon nanotubes embedded with Cu nanoparticles and highly dispersed Fe species. In 1 M NaOH + 0.1 M NaNO₃, Fe–Cu@NC delivers an NH₃ yield rate of 21.3 mg h⁻¹ cm⁻² at −0.9 V vs. RHE with a faradaic efficiency of 80.9%, while the faradaic efficiency reaches a maximum of 89.1% at −0.8 V vs. RHE with excellent cycling stability. Electrochemical measurements reveal increased double-layer capacitance and decreased charge-transfer resistance, demonstrating that Fe–Cu dual sites provide synergistic active centers for accelerating reaction kinetics. Our work offers a promising strategy for exploring high-efficiency electrocatalysts for nitrate-to-ammonia conversion.