Platinum nanoparticles employed in PEM fuel cells as catalysts for the hydrogen oxidation/oxygen reduction reactions (at the anode/cathode) are susceptible to poisoning by impurities such as airborne SO2 and chloride species.  The nature of the interaction with the Pt surface is completely different for the two species, as SO2 is a neutral molecule ready to be reduced/oxidized upon changing electrode potential while chloride ions are relatively stable negatively charged species. Here we use a combination of electrochemistry and X-Ray absorption near-edge structure spectroscopy (XANES) in order to explore the differences between the two species with respect to their interaction with Pt nanoparticles at different electrode potentials. As a result, speciation of adsorbed SO2 species on Pt is determined (both in inert (nitrogen) and an oxidative (oxygen) environment) and factors that contribute to the electrode potential effect in the presence of chloride ions at the fuel cell cathode are discussed.

Inflience of electrode potential on the adsorption of SO<sub>2 </sub>and chloride species on platinum nanoparticles

243rd National Meeting (2012)

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Inflience of electrode potential on the adsorption of SO2 and chloride species on platinum nanoparticles

Inflience of electrode potential on the adsorption of SO₂and chloride species on platinum nanoparticles