Characterization of Electrocatalysts by In Situ SAXS and XAS Investigations

Abstract

Size distributions, oxidation states and surface coverage of Pt catalyst particles on carbon supports were studied by anomalous small angle scattering (ASAXS) and X-ray absorption (XANES) with X-ray energies near the Pt-L3 absorption edge. The measurements were performed in electrochemical cells to trace electrochemical reactions in situ as a function of the applied electrochemical potential. In potential sweep experiments combined in situ ASAXS and XAS measurements give direct information on the electrochemical processes of methanol oxidation and iodine adsorption on the catalyst surface.