A novel 0D/2D WS2/BiOBr heterostructure with rich oxygen vacancies for enhanced broad-spectrum photocatalytic performance

Shuai Fu; Wei Yuan; Xianming Liu; Yunhui Yan; Haiping Liu; Li Li; Fengying Zhao; Jianguo Zhou

doi:10.1016/j.jcis.2020.02.077

A novel 0D/2D WS₂/BiOBr heterostructure with rich oxygen vacancies for enhanced broad-spectrum photocatalytic performance

J Colloid Interface Sci. 2020 Jun 1:569:150-163. doi: 10.1016/j.jcis.2020.02.077. Epub 2020 Feb 18.

Authors

Shuai Fu¹, Wei Yuan², Xianming Liu³, Yunhui Yan⁴, Haiping Liu¹, Li Li¹, Fengying Zhao¹, Jianguo Zhou⁵

Affiliations

¹ School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control (Ministry of Education), Henan Engineering Laboratory of Environmental Functional Materials and Pollution Control, Henan Normal University, Xinxiang 453007, Henan, PR China.
² School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450046, Henan, PR China.
³ College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, Henan, PR China.
⁴ Department of Chemistry, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453007, Henan, PR China.
⁵ School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control (Ministry of Education), Henan Engineering Laboratory of Environmental Functional Materials and Pollution Control, Henan Normal University, Xinxiang 453007, Henan, PR China; Key Laboratory of Green Chemical Media & Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Xinxiang 453007, Henan, PR China. Electronic address: zhoujgwj@sina.com.

PMID: 32105902
DOI: 10.1016/j.jcis.2020.02.077

Abstract

In this study, a novel 0D/2D WS₂/BiOBr heterostructured photocatalyst with rich oxygen vacancies was fabricated by a hydrothermal method. The WS₂ QDs/BiOBr-10 heterostructures exhibited a maximum removal rate of 92% towards ciprofloxacin (CIP) within 100 min under visible-light irradiation, which was 2.63- and 2.02- folds higher activity than that of pristine BiOBr and WS₂ QDs/BiOBr-10 with poor oxygen vacancies, respectively. In addition, the removal efficiencies of this photocatalyst towards various pollutants were 99% (Lanasol Red 5B), 95% (Rhodamine B), 85% (metronidazole), 96% (tetracycline) and 41% (Bisphenol A), respectively. Besides, the simultaneous photocatalytic degradation showed the competitive interactions between these organic contaminants for the active species, decreasing the removal efficiency for CIP. However, the simultaneous photocatalytic oxidation of CIP and reduction of Cr(VI) improved the utilization efficiency of photo-induced electrons and holes, resulting in high removal efficiencies for both CIP and Cr(VI). Three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs) were used to investigate the degradation of CIP molecules. The synergistic effect of heterostructure and oxygen vacancies greatly assisted in the removal of organic pollutants, attributing to the enhanced visible-light harvesting and effective separation of photo-induced electron-hole pairs. Furthermore, trapping experiments and ESR results demonstrated that the CIP removal was dominated by the direct oxidation of holes (h⁺), whereas the hydroxyl radicals (OH) and superoxide radicals (O₂^-) acted as auxiliary active species. This study provides a new way to rationally design and construct active 0D/2D pattern heterojunction photocatalysts for environmental remediation.

Keywords: Oxygen vacancies; Quantum dots; Simultaneous photodegradation; Synergistic effect; WS(2)/BiOBr.