Bandgap Widening of Titania through Semiconductor Support Interactions
| Autor: | Marc Gärtner, Paul Müller, Horst Kisch, Viatcheslav Dremov |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Valence (chemistry)
Materials science Diffuse reflectance infrared fourier transform Band gap business.industry Analytical chemistry chemistry.chemical_element Atomic and Molecular Physics and Optics law.invention Semiconductor chemistry Absorption edge X-ray photoelectron spectroscopy law Calcination Physical and Theoretical Chemistry business Titanium |
| Zdroj: | ChemPhysChem. 6:714-718 |
| ISSN: | 1439-4235 |
| DOI: | 10.1002/cphc.200400185 |
| Popis: | Silica-supported titania powders with 50, 36, 13 and 4 wt% of TiO2 (TiO2-50/SiO2, TiO2-36/SiO2, TiO2-13/SiO2 and TiO2-4/SiO2) were prepared by hydrolysis of TiCl4 in the presence of silica, followed by calcination at 500 degrees C. The formation of Ti-O-Si linkages was confirmed by diffuse reflectance infrared Fourier transform spectroscopy. Atomic force microscopy indicated the presence of titania crystals larger than 15 nm. All supported materials exhibited a blue-shift of the TiO2 absorption edge, which was attributed to an electronic semiconductor support interaction. Bandgap energies of TiO2-50/SiO2, TiO2-36/SiO2, TiO2-13/SiO2 and TiO(2)4/SiO2 were measured to be 3.28, 3.36, 3.40 and 3.42 eV, respectively, as compared to 3.15 eV for unsupported TiO2. From these values, and from the quasi-Fermi level of electrons, a high anodic shift of both the valence and the conduction band was estimated. X-ray photoelectron spectroscopy (XPS) measurements of oxygen 1s- and titanium 2p-binding energies confirmed the anodic shift of the band edges. |
| Databáze: | OpenAIRE |
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