Ampere-Level Nitrate Electroreduction to Ammonia over Monodispersed Bi-Doped FeS 2 .

Electrochemical conversion of NO 3 - into NH 3 (NO 3 RR) holds an enormous prospect to simultaneously yield valuable NH 3 and alleviate NO 3 - pollution. Herein, we report monodispersed Bi-doped FeS 2 (Bi-FeS 2 ) as a highly effective NO 3 RR catalyst. Atomic coordination characterizations of Bi-FeS 2 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 3 - -to-NH 3 pathway, while suppressing the competitive hydrogen evolution, leading to a high NO 3 RR selectivity and activity. Consequently, the specially designed flow cell equipped with Bi-FeS 2 exhibits a high NH 3 yield rate of 83.7 mg h -1 cm -2 with a near-100% NO 3 - -to-NH 3 Faradaic efficiency at an ampere-level current density of 1023.2 mA cm -2 , together with an excellent long-term stability for 100 h of electrolysis, ranking almost the highest performance among all reported NO 3 RR catalysts.