We report on our work using X-ray absorption spectroscopy to measure the structure and chemical state of supported Pd nanoparticles during the Pd-catalyzed hydrodeoxygenation of phenol in hydrogen-saturated water at 473 K. The Pd-Pd distances that we measured during the reaction suggest that hydrogen is present in and on the particles. When the phenol was near totally converted, the spectra showed a lengthening of the Pd-Pd bond which we attribute to the increased absorption of hydrogen by the particles, but the particles did not otherwise change upon their exposure to water or reactants; nor did the spectra show any effect from the interaction of the Pd particles with their supports (activated carbon, Al2O3, SiO2). The experimental results are consistent with ab initio molecular dynamic simulations that show the interactions of water with Pd metal are relatively weak and that those interactions become even weaker when hydrogen is incorporated into the metal particles.

X-ray absorption spectroscopy of supported palladium catalysts during hydrodeoxygenation of phenol in water

245th National Meeting (2013)

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