High-pressure zinc oxide phase as visible-light-active photocatalyst with narrow band gap

Hadi Razavi-Khosroshahi, Kaveh Edalati, Ji Wu, Yuki Nakashima, Makoto Arita, Yoshifumi Ikoma, Masaaki Sadakiyo, Yuji Inagaki, Aleksandar Staykov, Miho Yamauchi, Zenji Horita, Masayoshi Fuji

Research output: Contribution to journalArticlepeer-review

125 Citations (SciVal)

Abstract

Wide band gap of pure ZnO with wurtzite crystal structure (3.1-3.4 eV) limits its photocatalytic activity to the ultraviolet (UV) region of solar spectrum. High-pressure rocksalt polymorph of ZnO can theoretically show narrow band gap; however, the rocksalt phase is unstable at ambient pressure. Herein, rocksalt phase with large fractions of oxygen vacancies is successfully stabilized at ambient conditions by inducing plastic strain in pure ZnO under 6 GPa using the High-Pressure Torsion (HPT) method. Formation of rocksalt phase reduces the band gap of ZnO to 1.8 eV, which is in good agreement with the first-principles calculations, and significantly improves the photocatalytic activity under visible light.

Original languageEnglish
Pages (from-to)20298-20303
Number of pages6
JournalJournal of Materials Chemistry A
Volume5
Issue number38
DOIs
Publication statusPublished - 1 Sept 2017

Funding

K. E. thanks Kyushu University for the Qdai-Jump Research grant (No. 28325) and the MEXT, Japan, for a Grant-in-Aid for Scientic Research (B) (No. 16H04539). J. W. thanks the funding from JSPS and NSF, under the JSPS-NSF Partnership for International Research and Education (PIRE). This study was supported in part by the Japan Science and Technology Adaptable and Seamless Technology transfer Program through target-driven R&D (JST A-STEP), Japan, in part by the Core Research for Evolutional Science and Technology (CREST), in part by a Grant-in-Aid for Scientic Research (S) from the MEXT, Japan (No. 26220909), and in part by WPI-I2CNER. The HPT process was carried out in the International Research Centre on Giant Straining for Advanced Materials (IRC-GSAM) at Kyushu University.

ASJC Scopus subject areas

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

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