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Isolation of titania nanoparticles in monolithic ultraporous alumina: Effect of nanoparticle aggregation on anatase phase stability and photocatalytic activity

Paper ID Volume ID Publish Year Pages File Format Full-Text
41251 45882 2011 6 PDF Available
Title
Isolation of titania nanoparticles in monolithic ultraporous alumina: Effect of nanoparticle aggregation on anatase phase stability and photocatalytic activity
Abstract

We report on the preparation of a new photocatalyst by impregnation of size-selected TiO2 nanoparticles into monolithic ultraporous alumina of θ and α polymorphs. The alumina matrix is prepared by selective surface oxidation of liquid Hg-alloys in a humid atmosphere at room temperature with subsequent annealing at 1100–1300 °C. An additional treatment with trimethylethoxysilane was used to mechanically reinforce the ultraporous structure. Monodispersed titanium-oxo-alkoxy nanoparticles were generated in a sol–gel reactor with rapid micromixing, then deposited by liquid colloid impregnation and thermally treated above 350 °C to form anatase TiO2. High-resolution TEM images show evidence of non-aggregated 5-nm nanoparticles in θ-alumina matrix at a mass loading of 26 wt.%, which conserve their anatase crystalline structure after the thermal treatment at temperatures as high as 1000 °C. The rutile phase appears only at T ≥ 1100 °C when particle size increases to ∼17 nm due to the aggregation. The photocatalytic activity (ethylene decomposition) of the non-aggregated nanoparticles is conserved over a wide temperature range, and it decreases as soon as the aggregation takes place.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (97 K)Download as PowerPoint slideHighlights► Titania nanoparticles were built in alumina matrices. ► Aggregation of the nanoparticles was shown to be prohibited. ► Nanocrystals in these alumina matrices retained their thermal stability. ► The non-aggregated titania nanoparticles show high photocatalytic activity.

Keywords
TiO2 nanoparticles; Ultraporous alumina; Aggregation state; Anatase polymorph stability; Photocatalytic activity
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Isolation of titania nanoparticles in monolithic ultraporous alumina: Effect of nanoparticle aggregation on anatase phase stability and photocatalytic activity
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 402, Issues 1–2, 31 July 2011, Pages 156–161
Authors
, , , , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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