Role of surface-purity in photocatalytic activity of nanocrystalline anatase–titania processed via polymer-modified sol–gel

Nanocrystalline titania powders have been synthesized via conventional and modified sol–gel using an alkoxide precursor for different R , the ratio of molar concentration of water to that of alkoxide precursor, and calcination temperature. The apparent first-order reaction rate-constant obtained for...

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Bibliographic Details
Published in:Journal of sol-gel science and technology 2008-02, Vol.45 (2), p.165-178
Main Authors: Baiju, K. V., Shukla, S., Sandhya, K. S., James, J., Warrier, K. G. K.
Format: Article
Language:English
Subjects:
Anatase
Catalytic activity
Ceramics
Chemistry
Chemistry and Materials Science
Colloidal gels. Colloidal sols
Colloidal state and disperse state
Composites
Deactivation
Exact sciences and technology
General and physical chemistry
Glass
Hydroxypropyl cellulose
Inorganic Chemistry
Materials Science
Nanocrystals
Nanotechnology
Natural Materials
Optical and Electronic Materials
Organic compounds
Original Paper
Photocatalysis
Photocatalysts
Photochemistry
Physical chemistry of induced reactions (with radiations, particles and ultrasonics)
Polymers
Precursors
Purity
Sol-gel processes
Specific surface
Surface area
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Summary:Nanocrystalline titania powders have been synthesized via conventional and modified sol–gel using an alkoxide precursor for different R , the ratio of molar concentration of water to that of alkoxide precursor, and calcination temperature. The apparent first-order reaction rate-constant obtained for the powder synthesized via conventional sol–gel is comparable with that of commercial Degussa-P25. Conventional sol–gel has been modified using the hydroxypropyl cellulose polymer to increase the specific surface area of the photocatalyst; and hence, to further enhance its photocatalytic activity. Although higher specific surface area and smaller average nanocrystallite size have been obtained for the powders synthesized via modified sol–gel, they exhibit reduced photocatalytic activity relative to that of powders synthesized via conventional sol–gel. The deactivation of the present photocatalyst has been explained on the basis of reduced surface-purity of the powders after processing via modified sol–gel as induced by the presence of surface-residual organic compounds.
ISSN:0928-0707
1573-4846
DOI:10.1007/s10971-007-1653-4