Preparation of catalytically efficient precious metallic colloids by γ-irradiation and characterization

Polymer (polyvinylpyrrodione, PVP)-protected Ag, Au, Pd, and Pt colloids were prepared in water and organic solvents (acetone/2-propanol = 1/1, vol.%) by γ-irradiation. UV-visible spectrum of the colloidal solution shows the characteristic bands of surface resonance and gives evidence for the formation of nanoparticles. Nanopowders of precious metals (Ag, Au, Pd, and Pt) were obtained by self-assembling the thiol group of mercaptosuccinic acid (MSA) with the surface of the metal particles. Transmission electron microscopy and X-ray diffraction were used for characterizing the nanopowders. Results from high-performance liquid chromatography (HPLC) give evidence that Pd and Ag colloids in aqueous solution and organic solvents can be effectively used for the hydrogenation of cis,cis-1,3-cyclooctadiene (COD).