Hydrophilic-Hydrophobic Character of DMFC Cathode Catalyst Layers

DMFC composite cathodes, prepared from a 60 wt% Pt/Vulcan catalyst and by simultaneous deposition of Nafion and PTFE binders, were characterized in oxygen and nitrogen saturated H2SO4 0.5M solution by means of cyclic voltammetry and electrochemical impedance spectroscopy. The results showed the importance of the simultaneous presence in the catalyst layer structure of the hydrophilic and hydrophobic components, to provide the paths for the proton conduction and for the continuous supply of oxygen to the active sites.