Oxygen reduction reaction (ORR) activity of carbon nitride (CNx) is improved upon dispersing it on polyacrylonitrile (PAN) nanofiber using electrospinning technique. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy are used to study the morphology, size, form of nitrogen group present and bond structure of CNx/PAN nanofibers. Improvement in ORR activity of CNx/PAN nanofibers is observed compared to native CNx nanoparticles as per cyclic and linear sweep voltammetries. Onset potential and current density of CNx/PAN nanofibers for ORR is slightly lesser than that of commercial Pt/C (40:60% by weight). Rotating ring disk electrode (RRDE) voltammetry employed to study ORR mechanism on CNx/PAN nanofibers confirms four-electron pathway for ORR and water formation. In-situ FTIR coupled with voltammetry reveals continuous water formation, which is the ORR product, within the active potential range. Stability of the ORR catalytic activity of CNx/PAN is ascertained by 6000 repetitions of linear sweep voltammetry studies coupled with FFIR. (C) 2016 Elsevier B.V. All rights reserved.