Performance of sputter-deposited platinum cathodes with Nafion and carbon loading for direct methanol fuel cells

Cathodes prepared by spreading the mixture of Nafion, carbon and butyl acetate (NCB) solution on sputter-deposited Pt showed an increase in current densities and mass activities for the ORR. These may suggest an increase in catalyst active sites. Moreover, results of AC impedance analysis showed a decrease in charge transfer resistance and an increase in double layer capacitance for a sputter-deposited Pt cathode with NCB spread. Consequently, effects of NCB on cathodic polarization were explained by supplying protonic and electronic conduction paths to electrochemically inactive Pt with the oxygen diffusion path maintained. Mass activities were found about fifteen times higher than a Pt/C cathode prepared by a conventional method.