Control of Metal Dispersion, Chemical Composition and Texture of Palladium-Zinc Catalysts on Mesoporous Titania
3rd International Conference on Chemical Engineering and Advanced Materials
14-28 Nov 2011
International Review of Chemical Engineering - Rapid Communications
, E-ISSN: 2035-1763
||PdZn Colloids, PdZn Nanoparticles, Polyol Method, Mesoporous Titania Coating
Okhlopkova Lyudmila B.
Kerzhentsev Mikhail A.
Ismagilov Zinfer R.
Boreskov Institute of catalysis
Institute of Coal Chemistry and Material Science
Nanoparticle-doped mesoporous titania coatings were synthesized by incorporation of PdZn nanoparticles into support sol and deposition of the resulting sol on the inner surface of a fused silica capillary. This method allows controlling the chemical nature of the film, the porosity, metal dispersion and loading with an active species. The structural properties, chemical composition and morphology of the active component and the support were studied by means of TEM, EDS, ICP AES, X-ray diffraction and N2 adsorption. Monodispersed PdZn bimetallic colloidal particles were prepared by polyol method in the presence of polyvinylpyrrolidone. The average particle size ranging from 1.8-4.3 nm was found to depend on the amount of PVP added and NaOH concentration. The bulk composition of nanoparticles depends on concentrations of the precursors and NaOH. The reaction mechanism is shown to involve the oxidation of ethylene glycol to mainly glyoxal and glycolic acid, while the metal Pd salts are reduced to form catalysts for Zn2+ ions reduction. Palladium-zinc-incorporated mesoporous TiO2 films were synthesized by a sol-gel method using a nonionic structure-directing agent Pluronic F127. The control of the pore size of the mesoporous titania was achieved by adding co-surfactants, such as n-butanol. The influence of the activation conditions on crystallite size and composition of metal particles was investigated.