A composite consisting of intermetallic Ni3Fe and nitrogen-doped carbon for electrocatalytic water oxidation: The effect of increased pyridinic nitrogen dopant

Abstract Nitrogen-doped carbon (NC) has been studied as electrocatalysts or electrocatalyst support and the nitrogen content in carbon matrix is mainly dependent on the nitrogen-rich precursors. In this study, we prepare a composite consisting of intermetallic Ni3Fe and NC (NC@NiFe) via simply heating under ammonia and argon mixed gas atmosphere (Ar/NH3), aiming to further increase the nitrogen content. Compared to NC@NiFe, the NH3-derived electrocatalyst has more N atoms which are in the form of pyridinic N in carbon structure, significantly improving the electron transport efficiency and reaction kinetics, and thereby further boosting the electrocatalytic activity. This work demonstrates that the introduction of ammonia gas flow during calcination is a simple and effective strategy to increase the nitrogen content for engineering NC-based electrocatalysts toward high-performance water splitting.