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Sol–gel nanoparticulate mesoporous films with enhanced self-cleaning properties

Paper ID Volume ID Publish Year Pages File Format Full-Text
26832 43981 2010 7 PDF Available
Title
Sol–gel nanoparticulate mesoporous films with enhanced self-cleaning properties
Abstract

This paper presents a brief overview of the work done in our group concerning a versatile approach for the elaboration of TiO2-based photocatalytic coatings through the use of preformed TiO2 colloidal particles dispersed within a surfactant-templated mesoporous silica binder. Investigation of the influence of porosity on the photocatalytic efficiency of these films showed that the major impact arises from diffusion of the pollutant molecules (stearic acid) within the volume of the film, thus improving the action of the radicals photogenerated at the surface of the TiO2 particles. Starting from standard films elaborated using a commercial colloid, we showed that our approach allows a systematic investigation of any systems available as a colloidal suspension. A first example is given on titanium dioxide nanopowders (calcined Millennium or Degussa P25 particles). A grinding process was developed allowing the recovery of these powders as suspension of 120 nm aggregates that can be subsequently incorporated within mesoporous silica films. The obtained films exhibited photocatalytic performances similar to those of the standard films directly synthesized with the Millennium colloid. This result implies that the influence of the microstructure on photocatalytic efficiency is mainly governed by the silica matrix, allowing the investigation of almost any compounds even those synthesized through conventional solid state reaction at high temperature. We also developed an original process to prepare colloidal solutions of N-doped TiO2 particles obtained by nitridation treatment at high temperature. Investigation of the doping and photocatalytic efficiency under visible light irradiation evidenced the competition between nitrogen insertion and detrimental Ti4+ reduction. The latter effect may be somewhat limited by a post-treatment under air that re-oxidize the Ti3+ while preserving part of the inserted nitrogen.

Keywords
Self-cleaning; Photocatalysis; Sol–gel coatings; Mesoporous silica; N-doped TiO2
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 216, Issues 2–3, 15 December 2010, Pages 142–148
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us