Microelectrode simulation of anode in polymer electrolyte fuel cells

Active sites for hydrogen oxidation reaction on anode in Polymer Electrolyte Fuel Cells (PEFC) was simulated by inserting platinum microelectrode into a perfluorinated sulfonic acid particle, Nafion(R) NR50, under hydrogen atmosphere. Hydrogen oxidation current at different insertion depths was measured. For comparison, the current dependencies on the insertion depth was also calculated using a cylindrical diffusion model. The results indicated that hydrogen oxidation reaction at the Nafion/platinum interface proceeds under diffusion limiting conditions assuming a local current density maximum.