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 language | English |
|---|---|
| Pages (from-to) | 20298-20303 |
| Number of pages | 6 |
| Journal | Journal of Materials Chemistry A |
| Volume | 5 |
| Issue number | 38 |
| DOIs | |
| Publication status | Published - 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 Scientic 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 Scientic 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
