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Flame-coating of titania particles with silica

Teleki, A. ; Pratsinis, S.E. ; Wegner, K. ; Jossen, R. ; Krumeich, F.

In: Journal of Materials Research, 2005, vol. 20, no. 5, p. 1336-1347

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    Titre
    • Flame-coating of titania particles with silica
    Auteur
    • Teleki, A.. Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
    • Pratsinis, S.E.. Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
    • Wegner, K.. Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
    • Jossen, R.. Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
    • Krumeich, F.. Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8093 Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Journal of Materials Research, 2005, vol. 20, no. 5, p. 1336-1347. Cambridge University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:293129
    Summary
    Silica/titania composite particles were prepared by co-oxidation of titanium-tetra-isopropoxide and hexamethyldisiloxane in a co-flow diffusion flame reactor. The influence of precursor composition on product powder characteristics was studied by x-ray diffraction, nitrogen adsorption, electron microscopy, elemental mapping, and energy-dispersive x-ray analysis. The flame temperature was measured by Fourier transform infrared spectroscopy. The evolution of composite particle morphology from ramified agglomerates to spot- or fully coated particles was investigated by thermophoretic sampling and transmission/scanning electron microscopy. At 40-60 wt% TiO2, particles with segregated regions of silica and titania were formed, while at 80 wt% TiO2 rough silica coatings were obtained. Rapid flame-quenching with a critical flow nozzle at 5 cm above the burner nearly halved the product particle size, changed its crystallinity from pure anatase to mostly rutile and resulted in smooth silica coatings on particles containing 80 wt% TiO2