On the Origin of Electrocatalytic Oxygen Reduction Reaction on Electrospun Nitrogen–Carbon Species

Nitrogen–carbon (N–C) species is a potential electrocatalyst for oxygen reduction reaction (ORR) in electrochemical energy conversion cells, but its mechanistic origin of ORR on the N–C surface is still unclear. We show our facile approach to the synthesis of highly active Co-modified N–C catalyst and investigated the origin of ORR activity of electrospun N–C species by removing the metal with hydroxide carbon etching and acid metal leaching. Through the detailed investigation on the origin of ORR electrocatalysis for electrospun N–C nanofibers, we revealed that pyrrolic-N and highly graphitized carbon structure are mainly responsible for the enhanced ORR activity of metal-free N–C nanofiber and embedded Co metal got involved in the creation of the pyrrolic N site.