Alteration of the membrane electrode assemblies during direct methanol fuel cell activation process

This research is aimed to investigate the alteration of the membrane electrode assemblies (MEAs) and the anode catalysts (PtRu/C) as well as cathode catalysts (Pt/C) during the activation process in DMFCs by using water-boiling activation method and the constant voltage discharge activation method. The polarization curves show that the performances of the activated MEAs are greatly increased. The electrochemical impedance spectra (EIS) reveal that the resistances of the activated MEAs are decreased. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns show that the particle sizes of catalysts increase in both the anode and cathode. Electrochemical surface areas (ESAs) of anode and cathode catalysts were evaluated by CO-stripping and hydrogen-desorption test, respectively. It was found that the ESAs of the anode and cathode catalysts increase by 20.9% and 5.0%, respectively, although the particle sizes of the catalysts increase. It is proved that the constant voltage discharge activation method is more beneficial to activating the performance of MEAs compared to the water-boiling activation method.