Asymmetric Fe Single Atom on BN for Boosted Nitrate Electroreduction to Ammonia

Abstract

FeN2O2-BN has been proposed as an efficient electrocatalyst for promoting the nitrate reduction reaction (NO3RR). This catalyst achieves a maximum Faraday efficiency (FE) of 94.24%, with an ammonia (NH3) yield of 8.91 mg h⁻¹ mg cat⁻¹. Under a potential of -0.4 V in 0.05 M KNO3 and 0.1 M KOH, the catalyst exhibits excellent stability during long-term electrolysis. In situ electrochemical experiments elucidate the reaction pathway that favors NH3 formation. Theoretical calculations indicate that the asymmetric FeN2O2 facilitates water dissociation, enhances nitrate adsorption, and lowers the energy barrier of the rate-determining step. Simulated charge distribution analysis confirms that the iron monatomic site serves as the primary active centre for the NO3RR.