Electrochemical ammonia synthesis via nitrate reduction on Fe single atom catalyst

Electrochemically converting nitrate, a widespread water pollutant, back to valuable ammonia is a green and delocalized route for ammonia synthesis and a potential alternative to Haber–Bosch. Here a Fe single atom catalyst (SAC) enables selective and active nitrate reduction to ammonia with maximal Faradaic efficiency of ~75% and yield rate up to ~20,000 µg h−1 mgcat−1 (0.46 mmol h−1 cm−2). The isolated Fe sites suppress N–N coupling required for N2 formation, promoting NH3 selectivity. Density functional theory (DFT) reveals the reaction mechanism and identifies NO*→HNO* and HNO*→N* as potential limiting steps on atomically dispersed Fe sites.