Direct Relationship between Carbon Corrosion and Cathode Potential during Fuel Starvation in PEMFC

Fuel starvation during start-up and shut-down processes affected the performance of proton exchange membrane fuel cell significantly. Fuel starvation was intentionally made by supplying hydrogen and air into anode side alternatively and the individual electrode potential was in-situ measured with dynamic hydrogen electrode (DHE). Cathode potential was raised up to 1.6 V when air / hydrogen boundary developed on anode side. The development of high cathode potential caused the oxidation of carbon support and the amount of CO2 evolution is proportional to the cathode potential above 1.0 V. Above ~1.2 V, CO was electrochemically generated and a small amount of SO2 was formed above ~1.3 V. Although higher cathode potential was induced irrespective of cell temperature, the oxidation of carbon support is remarkably retarded at low temperature.