Femtosecond Diffuse-Reflectance Spectroscopy of Various Commercially Available TiO2 Powders |
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| Authors: | Yoshinori Murakami Junichi Nishino Takuya Mesaki Yoshio Nosaka |
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| Affiliation: | 1. Department of Materials Engineering , Nagaoka National College of Technology , Nagaoka, Japan murakami@nagaoka-ct.ac.jp;3. Department of Chemistry and Biology Engineering , Fukui National College of Technology , Sabae, Japan;4. Department of Chemistry , Nagaoka University of Technology , Nagaoka, Japan |
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| Abstract: | The transient absorption properties of several commercially available TiO2 photocatalysts were investigated by femtosecond diffuse-reflectance spectroscopy. Using femtosecond diffuse-reflectance spectroscopy, the quantities and rates of the initial trapping processes of holes and electrons generated by the photoexcitation of TiO2 photocatalysts were investigated. It was found that the total amounts of trapped electrons for the pure-anatase and pure-rutile TiO2 became smaller with increasing particle size, but increased again when the particles’ diameters were larger than 50 nm. The anatase–rutile mixed TiO2 photocatalysts were found to have smaller amounts of trapped electrons compared with pure-anatase and pure-rutile TiO2 photocatalysts. The lifetimes of trapped holes of various TiO2 photocatalysts were also investigated, and it was found that the lifetimes were proportional to the anatase–rutile mixed ratios. |
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| Keywords: | anatase charge separation diffuse reflectance femtosecond rutile TiO2 |
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