Oxygen vacancy-rich high-pressure rocksalt phase of zinc oxide for enhanced photocatalytic hydrogen evolution

Yu Shundo; Thanh Tam Nguyen; Saeid Akrami; Parisa Edalati; Yuta Itagoe; Tatsumi Ishihara; Makoto Arita; Qixin Guo; Masayoshi Fuji; Kaveh Edalati

doi:10.1016/j.jcis.2024.04.010

Oxygen vacancy-rich high-pressure rocksalt phase of zinc oxide for enhanced photocatalytic hydrogen evolution

J Colloid Interface Sci. 2024 Jul 15:666:22-34. doi: 10.1016/j.jcis.2024.04.010. Epub 2024 Apr 2.

Authors

Yu Shundo¹, Thanh Tam Nguyen¹, Saeid Akrami², Parisa Edalati³, Yuta Itagoe⁴, Tatsumi Ishihara⁵, Makoto Arita⁶, Qixin Guo⁷, Masayoshi Fuji⁸, Kaveh Edalati⁹

Affiliations

¹ WPI, International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395, Japan; Mitsui Chemicals, Inc. - Carbon Neutral Research Center (MCI-CNRC), Kyushu University, Fukuoka 819-0395, Japan.
² Institutes of Innovation for Future Society, Nagoya University, Nagoya 464-8603, Japan.
³ Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Tajimi 507-0033, Japan.
⁴ Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
⁵ WPI, International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395, Japan; Mitsui Chemicals, Inc. - Carbon Neutral Research Center (MCI-CNRC), Kyushu University, Fukuoka 819-0395, Japan; Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
⁶ Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
⁷ Department of Electrical and Electronic Engineering, Synchrotron Light Application Center, Saga University, Saga 840-8502, Japan.
⁸ Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Tajimi 507-0033, Japan; Advanced Ceramics Research Center, Nagoya Institute of Technology, Tajimi 507-0033, Japan.
⁹ WPI, International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395, Japan; Mitsui Chemicals, Inc. - Carbon Neutral Research Center (MCI-CNRC), Kyushu University, Fukuoka 819-0395, Japan. Electronic address: kaveh.edalati@kyudai.jp.

PMID: 38583207
DOI: 10.1016/j.jcis.2024.04.010

Abstract

The generation of hydrogen as a clean energy carrier by photocatalysis, as a zero-emission technology, is of significant scientific and industrial interest. However, the main drawback of photocatalytic hydrogen generation from water splitting is its low efficiency compared to traditional chemical or electrochemical methods. Zinc oxide (ZnO) with the wurtzite phase is one of the most investigated photocatalysts for hydrogen production, but its activity still needs to be improved. In this study, an oxygen-deficient high-pressure ZnO rocksalt phase is stabilized using a high-pressure torsion (HPT) method, and the product is used for photocatalysis under ambient pressure. The simultaneous introduction of oxygen vacancies and the rocksalt phase effectively improved photocatalytic hydrogen production to levels comparable to benchmark P25 TiO₂, due to improving light absorbance and providing active sites for photocatalysis without any negative effect on electron-hole recombination. These results confirm the high potential of high-pressure phases for photocatalytic hydrogen generation.

Keywords: Oxygen vacancy; Photocatalyst; Photocatalytic hydrogen production; Rocksalt high-pressure phase; Severe plastic deformation.