Proton exchange membrane fuel cell (PEMFC) possesses many attractive features,such as high power density,rapid start-up,and high efficiency for hydrogen-based fuel cells [1].The fuel of PEMFC is generally produced by steam reforming of hydrocarbons and followed with the water-gas shift reaction.Thus generated H2-rich gases generally contain about 1 vol.% CO.However,the anode of PEMFC is sensitive to the poisoning effect of trace amount of CO.