| Co-Investigator(Kenkyū-buntansha) |
MATSUOKA Masaya Osaka Prefecture University, College of Engineering, Research Associate, 工学部, 助手 (80305648)
YAMASHITA Hiromi Osaka Prefecture University, College of Engineering, Associate Professor, 工学部, 助教授 (40200688)
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| Research Abstract |
The photocatalytic degradation of various toxic compounds in aqueous solution using fine TiOィイD22ィエD2 particles has been investigated by many researchers, however, to avoid the filtration and suspension of the small particle photocatalysts, the design of an effective transparent TiOィイD22ィエD2 thin film photocatalyst is strongly desired. In this research project, transparent TiOィイD22ィエD2 thin film photocatalysts were prepared on transparent porous Vycor glass (PVG) by the ionized cluster beam (ICB) method. UV-Vis and XAFS investigations revealed the formation of uniform thin anatase TiOィイD22ィエD2 films with good crystallinity, even in the case of a film thickness of less than 300 nm. These thin TiOィイD22ィエD2 films were found to efficiently decompose NO into NィイD22ィエD2 and OィイD22ィエD2 photocatalytically under UV light irradiation. A modification of these TiOィイD22ィエD2 thin films were successfully carried out by applying an advanced metal ion-implantation technique with various transition meta
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l ions such as V and Cr. The UV-Vis absorption spectra of these metal ion-implanted TiOィイD22ィエD2 thin films were found to shift smoothly toward visible light regions and exhibited the ability to decompose NOx under irradiation with visible light longer than 450nm, while at the same time, maintaining a high photocatalytic activity under UV light irradiation. Furthermore, it was found that by using a magnetron sputtering method, the preparation of unique TiOィイD22ィエD2 thin films which decompose NO efficiently under visible light irradiation, without applying the ion-implantation of transition metal ions was possible. In-situ XPS measurements revealed that the Ti/O ratio of the TiOィイD22ィエD2 thin films gradually decrease from the surface to bulk phase of the catalyst, which plays an important role in the remarkable shift of the absorption band of the films toward visible light regions. Thus, it was shown that these unique TiOィイD22ィエD2 films newly prepared by such advanced ion-engineering techniques enable the utilization of as much as 35% of the solar beams that reach the earth, showing a remarkable contrast to the activity of commonly used TiOィイD22ィエD2 thin films which can utilize only about 4%. Less
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