Hydrogen oxidation reaction on thin platinum electrodes in the polymer electrolyte fuel cell

A method for measuring the kinetics of the hydrogen oxidation reaction (HOR) in a fuel cell under enhanced mass transport conditions is presented. The measured limiting current density was roughly 1600 mA cmPt−2, corresponding to a rate constant of the forward reaction in the Tafel step of 0.14 mol m−2 s−1 at 80 °C and 90% RH. The exchange current density for the HOR was determined using the slope at low overvoltages and was found to be 770 mA cmPt−2. The high values for the limiting and exchange current densities suggest that the Pt loading in the anode catalyst can be reduced further without imposing measurable voltage loss. Keywords: Hydrogen oxidation reaction, Limiting current density, Exchange current density, PEMFC, Fuel cell, Thermal evaporation