SPECTROELECTROCHEMICAL STUDY OF THE ROLE PLAYED BY CARBON FUNCTIONALITY IN FUEL-CELL ELECTRODES

X-ray absorption spectroscopy was used to identify specific types of n itrogen and sulfur-based carbon functionality present in the carbon bl ack supports of fuel cell anodes and cathodes. The effects of these fu nctional groups on the electrocatalytic performance of small platinum particles, dispersed on the carbon, during methanol oxidation and oxyg en reduction were assessed. Electrodes functionalized with nitrogen ha d enhanced catalytic activities toward oxygen reduction and methanol o xidation relative to untreated electrodes. Although electrodes with su lfur functionality had higher oxygen reduction activities than untreat ed carbons, the activity of these electrodes toward methanol oxidation was found to be lower than electrodes manufactured from untreated car bon. It was found that carbon supports functionalized with both nitrog en and sulfur initiated the formation of Pt particles smaller in size than those observed on untreated carbon supports.