Novel polyoxoanion stabilized colloids

COLL 515

Ryan M Richards and Lawrence D'Souza. School of Engineering and Science, International University Bremen, Campus Ring 8, 28759 Bremen, Germany
Metal colloids of Pd, Au, Ag and Ru have been stabilized by heteropolyanions (PW11O39)-7, (P2W18O62)-6, (Mo6O19)-2 and (PMo12O40)-3. The nano-systems were characterized using various instrumentation such as UV-Visible spectroscopy, dynamic light scattering, FT-IR spectroscopy, X-ray diffraction and transmission electron microscopy. The pH of the solution was found to play an important role in colloid stabilization/coagulation. The particle size distribution was found to be strongly dependent on the metal/stabilizer ratio and preparation protocol. The Pd colloid was found to be re-dispersible in water, methanol and acetonitrile while Ag was soluble only in water and methanol. The Pd system demonstrated high activity for the hydrogenation of 1-hexene and further examination of catalytic activity is on-going.