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－　　－7Published PaperFabrication of the Slightly Reduced TiO2 Photocatalyst Reacted Visible Light by the Microwave-H2-plasma ProcessingShota YAZAWA, Yusuke KUDO, Tetsuya NAKANISHI, Tomohiko TAKEUCHI,Shota ARAKI, Noboru KATAYAMA and Sumio KOGOSHIA photocatalyst is attracting widespread attention because it works semipermanently under light irradiation. A photocatalyst has useful characteristics such as an oxidative decomposition and a super-hydrophilicity. However, TiO2 photocatalysts which are often used can be activated only by ultraviolet rays. The ultraviolet rays for photoactivation of TiO2 are included nearly zero in indoor lights. If a photocatalyst can be activated with visible light as well as ultraviolet light, a photocatalyst can be used not only outdoors but also indoors. A slightly reduced TiO2 is one of visible light responsible photocatalysts. A slightly reduced TiO2 can be produced with H2-plasma surface processing. However, it is not so clear that the dependence of the performance on the processing parameters. In this study, we have focused on a H2-plasma processing time. The performance of a slightly reduced TiO2 under visible light irradiation is estimated from a decomposition rate of formaldehyde. It is found that the performance of the slightly reduced TiO2 improves as the plasma processing time become shorter although the amount of the visible light absorption becomes smaller. The performance of a slightly reduced TiO2 under visible light irradiation is also compared with that of a N-doped TiO2, which is the most popular visible light responsible photocatalyst. The result shows that the decomposition rate of formaldehyde by the slightly reduced TiO2 is three times or more than that by the N-doped TiO2.Keywords: Visible-light-responsible photocatalyst, Microwave-H2-plasma, TiO2水素マイクロ波プラズマ処理による可視光応答化酸素欠損型光触媒の製作　光の照射下で半永久的に使用することができ，酸化分解作用と超親水性作用を発揮する光触媒は広く注目を集めている。よく使用される光触媒として酸化チタン(TiO2)があるが，酸化チタンはそのままでは紫外線によってのみ活性化されるため，太陽光などの紫外線を含む光源がある場所では有効に働くのに対し，屋内など紫外光を含まない光源しかない場所では有効に働かないという問題がある。本研究では酸化チタンに水素マイクロ波プラズマ処理を行うことで酸素欠損型光触媒とし，可視光で活性化させることに成功した。また，ホルムアルデヒド分解試験を用いて光触媒の性能を評価することで，水素プラズマ処理の条件と可視光下での光触媒の性能の関係について詳細に調べた。実験結果より水素マイクロ波プラズマ処理により可視光応答化した酸化チタン光触媒は従来法である窒素ドープ型酸化チタン光触媒の3倍以上の性能を示すことがわかった。キーワード : 可視光応答型光触媒，水素マイクロ波プラズマJournal（掲載誌）Journal of the Institute of Electrostatics Japan, Vol.37, No.3, Page.138-143 (2016) http://www.iesj.org/content/les/pdf/papers/37/37-3-138.pdf