Ampere-Level Nitrate Electroreduction to Ammonia over Monodispersed Bi-Doped FeS.

Electrochemical conversion of NO into NH (NORR) holds an enormous prospect to simultaneously yield valuable NH and alleviate NO pollution. Herein, we report monodispersed Bi-doped FeS (Bi-FeS) as a highly effective NORR catalyst. Atomic coordination characterizations of Bi-FeS disclose that the isolated Bi dopant coordinates with its adjacent Fe atom to create the unconventional p-d hybridized Bi-Fe dinuclear sites. Operando spectroscopic measurements combined with theoretical calculations disclose that Bi-Fe dinuclear sites can synergistically enhance the hydrogenation energetics of NO-to-NH pathway, while suppressing the competitive hydrogen evolution, leading to a high NORR selectivity and activity. Consequently, the specially designed flow cell equipped with Bi-FeS exhibits a high NH yield rate of 83.7 mg h cm with a near-100% NO-to-NH Faradaic efficiency at an ampere-level current density of 1023.2 mA cm, together with an excellent long-term stability for 100 h of electrolysis, ranking almost the highest performance among all reported NORR catalysts.