In this work we propose a different alternative, the production of the support with the intrinsic formation of dopants in CNFs. N-doped carbon nanofibers were synthetized by electrospinning of polyacrylonitrile (PAN) followed by a two-step calcination process: stabilization and carbonization, the first was carried out under air atmosphere at 553 K while carbonization was conducted in inert atmosphere at five different temperatures, 873, 973, 1073, 1173 and 1273 K. X-ray Photoelectron spectroscopy experiments indicate that depending on the carbonization temperature this process produces different amounts of nitrogen species in the materials. For carbonization temperatures of 873 and 973 K, nitrogen species are mainly found in N-6 form (piridinic) while a small amount of nitrile groups is still present. For the materials with temperature treatment above 1073 K, N-Q (quaternary or graphitic nitrogen) becomes the most abundant nitrogen species, this indicate than the formed N-Q is much more stable than N-6 at higher temperatures.
The stability of the material was evaluated by cyclic voltammetry in acid media in anodic direction. The results indicate that all CNFs present a less positive oxidation onset potential in comparison to carbon Vulcan. This result agrees with thermogravimetric analysis in which N doped CNF decomposition (CO2 formation) is obtained at higher temperatures than commercial supports. Moreover, the CNFs were also evaluated as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline conditions. The preliminary results show that as the quantity of N-Q augments, the catalytic activity concomitantly increases as well, i.e. the onset potential for oxygen reduction increases.