Atomically Dispersed Sn Confined in FeS2 for Nitrate‐to‐Ammonia Electroreduction.

Electrocatalytic NO3− reduction to NH3 (NO3RR) is an efficient strategy to simultaneously mitigate NO3− contamination and produce sustainable NH3. Herein, atomically dispersed Sn confined in FeS2 (Sn‐FeS2) is reported as an effective and robust NO3RR catalyst, achieving a maximum NH3‐Faradaic efficiency of 96.7% with a corresponding NH3 yield rate of 15.8 mg h−1 cm−2, along with an excellent catalytic stability. Atomic coordination characterizations of Sn‐FeS2 unravel that single‐atomic Sn bonds with the surrounding Fe atoms to construct the unique p‐d hybridized Sn‐Fe pair sites. Combining theoretical investigations and operando spectroscopic measurements unveil that Sn‐Fe pair sites can synergistically promote the NO3− activation and N═O bond dissociation, accelerate the protonation energetics of NO3−‐to‐NH3 pathway and suppress the competing hydrogen evolution, eventually drastically enhancing the NO3RR activity and selectivity. [ABSTRACT FROM AUTHOR]