In-situ Synchrotron X-ray Spectroscopy of Ruthenium Nanoparticles Modified with Selenium for Oxygen Reduction Reaction

In-situ Se K edge X-ray spectroscopy measurements were carried out for selenium modified ruthenium nanoparticles during oxygen reduction. X-ray powder diffraction verified that the samples had pure Ru cores. In-situ XANES showed that there were significant amounts of oxidized Se in the Ru/Se samples that could be reduced by negative potentials. Selenium in the sample was found to oxidize at electrode potentials of 900 mV and higher (vs. RHE). Analysis of extended x-ray absorption fine structure shows an enhancement of the Se-Ru bonds during oxygen reduction reaction.