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

Graphical Strat talks : The density of FeN x active sites is increased by co-doping with trace Cu atoms. The as-prepared 20Fe10Cu-NC electrocatalyst exhibits outstanding oxygen reduction reaction performance in both alkaline and acid conditions. 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 FeN x 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 (E 1/2 ) 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 FeN 4 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.