Porous nitrogen-doped carbon nanofibers as highly efficient metal-free electrocatalyst for oxygen reduction reaction

Three kinds of polymer blend of poly(methyl methacrylate) (PMMA)/polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP)/PAN and cellulose acetate (CA)/PAN were converted into nitrogen-doped carbon nanofibers (NCNFs) by electrospinning combined with acid oxidation and NH3 etching. The NCNFs showed excellent electrocatalytic performance for oxygen reduction reaction (ORR) in acid media, probably being attributed to the good hydrophilicity and wettability, porous fibrous structure, ultra thin diameter of less than 50 nm, more exposed edge planes of pyrolytic graphitic carbons, and high proportion of pyridinic and quaternary nitrogen. The developed NCNFs show great potential as metal-free electrocatalyst for ORR in acid environment.