Palladium-Alloy Catalysts as Ethanol Tolerant Cathodes for Direct Alcohol Fuel Cell (DEFC) Applications

Abstract

Palladium and palladium-alloy catalysts cathode have shown a high degree of tolerance to ethanol during the ORR in an acid medium. In particular, it was shown that the onset potential for the ORR in the presence of 0.5M C2H5OH decreases by only 33 mV and 18 mV on palladium and palladium-cobalt catalysts, respectively. This decrease in the onset potential due to the presence of ethanol on the Pd-based catalysts is more than ten times lower than those observed on Pt electrodes (513 mV). On the other hand, the palladium-based catalysts do not show any peak current attributed to the electro-oxidation of ethanol, whereas the Pt-based catalyst exhibited a high peak current related to the oxidation of ethanol. The high activity of Pd and Pd-Co catalysts for the ORR, as well as their high level of tolerance to the ethanol make them suitable candidates for Direct Ethanol Fuel Cell applications.