Spectrum Pd K edge XAS fluorescence of 1 wt.% Pd/SiO2 at RT under He (after heating at 300C under H2) Spectrum Pd K edge XAS fluorescence of 1 wt.% Pd/SiO2 at RT under H2 (after heating at 300C under H2) Spectrum Pd K edge XAS fluorescence of PdO at RT