Chinese Journal of Catalysis ›› 2020, Vol. 41 ›› Issue (10): 1488-1497.DOI: 10.1016/S1872-2067(19)63409-1

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Microwave-assisted synthesis of defective tungsten trioxide for photocatalytic bacterial inactivation: Role of the oxygen vacancy

Wenquan Gua, Wanjun Wanga, Guiying Lia, Haojing Xiea, Po Keung Wongb, Taicheng Ana   

  1. a Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, Guangdong, China;
    b School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China
  • Received:2019-12-22 Revised:2020-01-31 Online:2020-10-18 Published:2020-08-15
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21607028, 41425015 and 41573086), the Research Grant Council of Hong Kong SAR Government (GRF14100115), Science and Technology Project of Guangdong Province (2017A050506049), Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01Z032), Innovation Team Project of Guangdong Provincial Department of Education (2017KCXTD012), and Leading Scientific, Technical and Innovation Talents of Guangdong Special Support Program (2016TX03Z094).

Abstract: Surface defect modulation has emerged as a potential strategy for promoting the photocatalytic activity of photocatalysts for various applications, while the impact of the oxygen vacancy on bacterial inactivation is still debated. In this study, oxygen vacancies were introduced to tungsten trioxide nanosheets (WO3-x) via a microwave-assisted route. The as-prepared WO3-x nanosheets exhibited excellent visible-light-driven photocatalytic activity toward E. coli K-12 inactivation, and 6 log orders of the bacterial cells could be completely inactivated within 150 min. The obtained bacterial inactivation rate constant was 15.2 times higher than that of pristine WO3 without oxygen vacancies, suggesting that the surface oxygen vacancy could significantly promote the bacterial inactivation efficiency. The mechanism study indicated that the inactivation of bacterial cells occurs via a direct h+ oxidation pathway. In addition, the role of the oxygen vacancy was studied in detail; the oxygen vacancy was found to not only promote interfacial charge separation but also tune the band structure of WO3, thereby leading to increased h+ oxidation power. Finally, a possible oxygen vacancy-dominated photocatalytic bacterial inactivation mechanism is proposed. This work is expected to offer new insights into the microwave-assisted synthesis of defective photocatalysts and the use of the oxygen vacancy for promoting photocatalytic antibacterial activities.

 

Key words: Photocatalysis, WO3, Microwave, Oxygen vacancy, Bacterial inactivation