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Flame-coating of titania particles with silica

Published online by Cambridge University Press:  03 March 2011

A. Teleki ,
S.E. Pratsinis ,
K. Wegner ,
R. Jossen  and
F. Krumeich
A. Teleki
Affiliation:
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
S.E. Pratsinis*
Affiliation:
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
K. Wegner
Affiliation:
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
R. Jossen
Affiliation:
Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8092 Zurich, Switzerland
F. Krumeich
Affiliation:
Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology Zurich (ETHZ), CH-8093 Zurich, Switzerland
*
a)Address all correspondence to this author. e-mail: pratsinis@ptl.mavt.ethz.ch
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Abstract

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.

Keywords

CompositeFlame synthesisNanoparticle
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 5 , May 2005 , pp. 1336 - 1347
Copyright
Copyright © Materials Research Society 2005

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