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Nafion has found utility in a wide variety of applications, particularly as the most commonly used electrolyte membrane in fuel cell technology. Despite decades of characterization by X-ray Photoelectron Spectroscopy (XPS), a dispute exists within literature over the proper assignment of oxygen binding energies from the ether and sulfonate functional groups present in Nafion. Here, we have employed highly oriented pyrolytic graphite (HOPG) as an internal standard to calibrate all XPS spectra and are able to correlate binding energies from C1s, O1s, F1s and S2p to the Nafion structure. Further, microscale heterogeneities inherent to this formulation of Nafion membranes are revealed through two-dimensional XPS mapping of membrane cross-sections as well as surface ablation via Ar + ion sputtering. Results clearly show Nafion membranes are comprised of two chemically distinct layers: a surface layer several microns thick that is comprised of sulfonate groups and an inner layer that shields the more non-polar perfluoroether moieties.

Infrared spectroscopy has been employed to study the chemisorption of CO by Pd crystallites supported on SO2. At 80 K, it has been found that the adsorption of terminally bound CO species on Pd saturated with bridged-CO species results in the stoichiometric conversion of two CO-bridged species to terminal-CO species for each terminal CO adsorbed. The local character of this stoichiometric conversion process suggests that local donor-acceptor concepts operate at the sites experiencing the conversion. Comparisons of behavior on small Pd crystallites and on Pt( 1 11) are made, and it is found that remarkable similarities exist as well as differences.

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