Optimization of Nafion content in Nafion–polyaniline nano-composite modified cathodes for PEMFC application

In this research several Nafion–Polyaniline nano-composite modified cathodes have been fabricated and evaluated in oxygen reduction reaction (ORR) in order to use in proton exchange membrane fuel cell (PEMFC). Modified cathodes made by the wide range of Nafion content (from 0 to 1.6 mg cm−2) and investigated in the acidic solution by different electrochemical techniques at 25 °C. The results indicate the activity of the modified electrodes is increased by employing of Nafion–Polyaniline nano-composite in the reaction layer, but there is an optimum value for Nafion content in the catalyst layer. The modified electrode impregnated by 0.4 mg cm−2 of Nafion shows the highest activity. Analysis of the surface morphology of the Nafion–polyaniline modified electrodes by scanning electron microscopy and electrochemical data reveal that the existence of polyaniline (PANI) nanofibers in the catalyst layer before adding Nafion solution, improves the homogeneity distribution of the ionomer in catalyst layer, change the morphology of electrode and increase the performance of gas diffusion electrodes (GDEs) in oxygen reduction reaction.