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

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

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)


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 â14 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.

Original languageEnglish
Pages (from-to)5103-5107
Number of pages5
JournalACS Catalysis
Issue number8
Publication statusPublished - 2016 Aug 5
Externally publishedYes


  • TiO-II (columbite)
  • high-pressure torsion (HPT)
  • hydrogen generation
  • severe plastic deformation (SPD)
  • titanium oxide (titania)
  • visible-light-active photocatalyst

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)


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