Photocatalytic hydrogen generation on low-bandgap black zirconia (ZrO2) produced by high-pressure torsion

Qing Wang, Kaveh Edalati, Yuta Koganemaru, Shohei Nakamura, Motonori Watanabe, Tatsumi Ishihara, Zenji Horita

Research output: Contribution to journalArticlepeer-review

67 Citations (Scopus)


Photocatalysis on semiconductors using solar energy sources provides a clean technology to produce hydrogen from water splitting. Although zirconia (ZrO2) is a semiconductor oxide, it is not generally considered as a photocatalyst owing to its poor light absorbance and wide bandgap (over 5 eV). In this study, black ZrO2 with a large concentration of lattice defects such as oxygen vacancies, dislocations and nanograin boundaries is stabilized by high-pressure torsion (HPT) straining. The black ZrO2, which experiences monoclinic-tetragonal phase transformations during the HPT process, shows large light absorption, a small bandgap, reduced conduction band energy and high photocatalytic activity for hydrogen evolution due the presence of oxygen vacancies. These results confirm that the introduction of strain-induced oxygen vacancies is a potential method to produce low-bandgap photocatalysts.

Original languageEnglish
Pages (from-to)3643-3650
Number of pages8
JournalJournal of Materials Chemistry A
Issue number7
Publication statusPublished - Feb 21 2020

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Renewable Energy, Sustainability and the Environment
  • General Materials Science


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