Boron Regulated Fe Single-Atom Structures for Electrocatalytic Nitrate Reduction to Ammonia

Electrocatalytic reduction of nitrate (NO₃RR) to ammonia offers a promising approach for mitigating the environmental impact of NO₃^–, while simultaneously enabling the synthesis of NH₃ under ambient conditions. Recently, single-atom catalysts (SACs) have been proven to have attractive activity on NO₃RR, and better catalysts with enhanced activity and stability are still in demand. Here, we report the efficient boosting of NH₃ production via the NO₃RR using boron-doped Fe SAC (Fe-BCN). Fe-BCN is a normal 12-hedral nanoparticle with a size of 500 nm. The NH₃ Faradaic efficiency of Fe-BCN reached 97.48%, with a high ammonia production rate of 2.17 mg cm^–2 h^–1, in an alkaline electrolyte environment at an electrode potential of −0.3 V vs reversible hydrogen electrode. Density functional theory calculations revealed the strategy of introduced B regulating the intermediate adsorption on Fe-BCN, which enhanced the NO₃RR activity. Furthermore, leveraging the high NO₃RR activity of Fe-BCN, a nitrate-zinc battery with a power density of 0.90 mW cm^–2 was constructed by using Fe-BCN as the cathode and zinc as the anode, respectively. This research demonstrates the broad prospects of Fe-BCN in the NO₃RR and provides insights for high-performance Fe SAC electrode materials.