XAFS Analysis of Pt and Pt-Ru Catalysts for PEFCs by In-Situ Measurements under Operating Conditions in the Fluorescence Mode

In‐situ X‐ray absorption fine structure (XAFS) is one of powerful spectroscopic techniques to analyze valence state and chemical bonding in Pt and Pt‐Ru electrocatalysts under fuel cell operating conditions. We measured Pt L3 and Ru K‐XAFS of Pt and Pt‐Ru electrocatalysts in fluorescence mode under different operation voltages using pure H2 or 97 ppm CO containing H2 as fuel gases that were fed to the anode. The radial structure functions that derived from the obtained XAFS spectra showed that the local structure around Pt and Ru atoms in the electrocatalysts changes depending on the operation voltage and shows difference with the existence of CO in the fuel gas.