Development of easy conversion process from titania-metal surface covered with thermodynamically stable passive film into anatase-TiO2 photocatalytic layer

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K05112
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26060:Metals production and resources production-related
• Research Institution: Tokyo University of Science, Yamaguchi
• Principal Investigator: Ishikawa Toshihiro 山陽小野田市立山口東京理科大学, 工学研究科, 教授 (60756104)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 金属チタン / 表面 / 光触媒機能 / アナターゼ型酸化チタン

Outline of Final Research Achievements

Surface functionalization of titanium metal is very attractive for bio- and environmental applications. This is because titanium metal is very stable and has a good biocompatibility. In this case, surface roughness and crystalline structure are important factors for obtaining effective characteristics. Titanium metal is usually covered with a surface passive film of thermodynamically stable rutile-TiO2 that grows as the heat treatment temperature in air increases. On the other hand, to obtain an anatase-TiO2 surface layer on titanium metal, we must employ specific treatments such as our previous method, which uses a silica-coexisting heat-treatment process.
In this research, the relationship between the fine structure formed on the titanium metal and the surface hydrophilic property was clarified, and the potential for the bio-application was discussed. The formed anatase-TiO2 coexisting with silica exhibited improved biocompatibility with good apatite formation.

Free Research Field

金属生産および資源生産関連

Academic Significance and Societal Importance of the Research Achievements

これまでは、金属チタン表面にアナターゼ型酸化被膜を形成させるには、強酸・強アルカリ処理と高圧条件の水熱合成法や、高電圧下で行われる陽極酸化法と言った比較的複雑な処理法が用いられており、簡便な大気中酸化のみで金属チタン表面の不動態膜をアナターゼ型酸化被膜に変換することを実現した報告は国内外で皆無である。したがって、本研究成果は、通常の大気中酸化では熱力学的に生成不可能な機能性酸化膜を、不動態化した金属表面に直接酸化により形成させる新しい技術基盤を構築するとともに、それを用いた安全で耐久性に優れた水質浄化装置も開発できることから、人々の健康と環境改善に幅広く貢献できる。