Tuning Nitrogen Configurations in Nitrogen‐Doped Graphene Encapsulating Fe 3 C Nanoparticles for Enhanced Nitrate Electroreduction

Abstract Electrochemical nitrate reduction reaction (NO 3 RR) offers a promising technology for the synthesis of ammonia (NH 3 ) and removal of nitrate in wastewater. Herin, we fabricate a series of Fe 3 C nanoparticles in controllable pyridinic‐N doped graphene (Fe 3 C@NG‐X) by a self‐sacrificing template method for the NO 3 RR. Fe 3 C@NG‐10 exhibits high catalytic performance with a Faradaic efficiency (FE) of 94.03 % toward NH 3 production at −0.5 V vs . Reversible hydrogen electrode (RHE) and an NH 3 yield rate of 477.73 mmol h −1  g cat −1 . Additionally, the catalyst also has a FE above 90 % across a broad potential range and NO 3 − concentration range (12.5–500 mM). During the electrocatalytic process, the material experienced structural reconstruction, forming Fe/Fe 3 C@NG‐X heterojunction. Experimental investigations demonstrate that the remarkable electrocatalytic activity is attributed to the high proportion of pyridinic‐N content, and the reconstruction further enhances the overall reduction process.