Visible-Light-Driven Photocatalytic Hydrogen Generation on Nanosized TiO2-II Stabilized by High-Pressure Torsion

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• 作者：Hadi Razavi-Khosroshahi ; Kaveh Edalati ; Masashige Hirayama ; Hoda Emami ; Makoto Arita ; Miho Yamauchi ; Hidehisa Hagiwara ; Shintaro Ida ; Tatsumi Ishihara ; Etsuo Akiba ; Zenji Horita ; Masayoshi Fuji
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：August 5, 2016
• 年：2016
• 卷：6
• 期：8
• 页码：5103-5107
• 全文大小：439K
• 年卷期：0
• ISSN：2155-5435

文摘

Photocatalytic activity of pure TiO₂ is limited to ultraviolet (UV) light due to the wide bandgap of anatase and rutile phases. The bandgap of high-pressure phases of TiO₂ can theoretically coincide with visible light, but these phases are unstable at ambient pressure. In this work, the high-pressure TiO₂-II (columbite) phase with large fractions of oxygen vacancies was stabilized by inducing plastic strain to anatase under 6 GPa. The material could absorb visible light as a consequence of bandgap narrowing by ∼0.7 eV. Formation of nanosized TiO₂-II enhanced the hydrogen generation efficiency under visible light, and the efficiency improved after removing the oxygen vacancies by annealing.