Iron, Copper and Nitrogen Co‐doped Carbon with Enhanced Electrocatalytic Activity towards Oxygen Reduction.

Iron‐nitrogen‐doped carbon (Fe‐NC) is an ideal candidate to replace Pt‐based oxygen reduction reaction (ORR) electrocatalysts due to its low cost and comparably high intrinsic activity. To further enhance the ORR performance of Fe‐NC electrocatalysts, efforts have been focused on two main methods. One is to enhance the intrinsic activity of FeNx sites through electronic and geometric regulation, and the other is to increase the density of active sites by introducing high‐nitrogen‐containing precursors or co‐doping methods. Herein, we report a strategy to further increase the Fe loading through the introduction of a trace amount of Cu atoms. Significant enhancement of the electrocatalytic ORR property is observed in the as‐prepared Fe and Cu co‐doped electrocatalyst with superior half‐wave potential (E1/2) in both alkaline and acid electrolyte. Experimental and theoretical study reveals that the introduction of a trace amount of Cu atoms is beneficial for the formation of FeN4 sites, owing to the reduced formation energy. This work opens up a wide avenue to further increase the Fe loading in Fe‐NC electrocatalysts through bimetal co‐doping method. [ABSTRACT FROM AUTHOR]