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Preparation of phosphated Zr-doped TiO2 exhibiting high photocatalytic activity through calcination of ligand-capped nanocrystals

Paper ID Volume ID Publish Year Pages File Format Full-Text
47958 46486 2009 9 PDF Available
Title
Preparation of phosphated Zr-doped TiO2 exhibiting high photocatalytic activity through calcination of ligand-capped nanocrystals
Abstract

We incorporated phosphate and pyrophosphate species into the surface lattice of Zr-doped TiO2 via calcination (>550 °C) of triocylphosphine oxide (TOPO)-capped nanocrystals that had been prepared using a non-hydrolytic sol–gel method. The phosphated Zr-doped TiO2 calcined at 550–750 °C exhibited 2.88–5.28-fold higher photocatalytic activities for decomposition of bisphenol A (BPA) than did P25. Moreover, the sample prepared through calcination at 950 °C performed an extraordinary activity which was 40.3 times higher than that of P25. The high surface reactivities were resulted from co-doing of TiO2 surface with Zr4+ and phosphate/pyrophosphate species. Calcination enhanced the reactivity at elevated temperatures because it changed the microstructures and surface properties of phosphated Zr-doped TiO2. The average crystallite size increased dramatically from 10.2–10.8 to 16.1 nm when the temperature increased from 750 to 950 °C. This change was associated with the formation of pyrophosphate species through condensation of the concentrated phosphate species. Dehydration resulted in substantial amounts of oxygen vacancies (OM/MS = 1.38) and Ti3+ ions in the surface layers of the phosphated Zr-doped TiO2 calcined at 950 °C. The dehydrated TiO2 displayed high affinity toward BPA with a maximum adsorption capacity of 5.35 mg/g. The appearance of signals for Ti4+-O2− in the EPR spectrum of the modified TiO2 in the dark indicated its high capability for the chemisorption of O2. In addition, the remarkable decrease in the intensities of trapped electrons in the sample under an O2 atmosphere revealed that efficient charge transfer occurred from the trapped sites to the electron scavenger. Thus, the phosphated Zr-doped TiO2 calcined at high temperatures exhibit improved adsorbability toward reactants and enhanced interfacial charge transfer, resulting in outstanding photocatalytic activity.

Keywords
Co-doping; Phosphated; Zr-doped TiO2; High photocatalytic activity; Bisphenol A
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Preparation of phosphated Zr-doped TiO2 exhibiting high photocatalytic activity through calcination of ligand-capped nanocrystals
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 90, Issues 1–2, 25 July 2009, Pages 233–241
Authors
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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