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

Abstract

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.