Double Z-scheme system of silver bromide@bismuth tungstate/tungsten trioxide ternary heterojunction with enhanced visible-light photocatalytic activity

Mengmeng Zhang; Youyi Zhu; Wenjun Li; Fangzhi Wang; Hongda Li; Xintong Liu; Weiwei Zhang; Chaojun Ren

doi:10.1016/j.jcis.2017.08.095

Double Z-scheme system of silver bromide@bismuth tungstate/tungsten trioxide ternary heterojunction with enhanced visible-light photocatalytic activity

J Colloid Interface Sci. 2018 Jan 1:509:18-24. doi: 10.1016/j.jcis.2017.08.095. Epub 2017 Aug 31.

Authors

Mengmeng Zhang¹, Youyi Zhu², Wenjun Li³, Fangzhi Wang¹, Hongda Li¹, Xintong Liu¹, Weiwei Zhang¹, Chaojun Ren¹

Affiliations

¹ Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, University of Science and Technology Beijing, Beijing 100083, China.
² Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100083, China.
³ Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, University of Science and Technology Beijing, Beijing 100083, China. Electronic address: wjli_ustb@163.com.

PMID: 28881201
DOI: 10.1016/j.jcis.2017.08.095

Abstract

The ternary heterojunction of silver bromide@bismuth tungstate/tungsten trioxide (AgBr@Bi₂WO₆/WO₃) was designed and synthesised by hydrothermal and deposition-precipitation approaches. The composites were characterised by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). The photoabsorption range and bandgaps of the photocatalysts were analysed by ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Compared with Bi₂WO₆/WO₃ or AgBr alone, the AgBr@Bi₂WO₆/WO₃ composites displayed higher visible-light photocatalytic performance for degrading rhodamine B (RhB). AgBr@Bi₂WO₆/WO₃ with 40% AgBr concentration was optimum for photocatalytic activity. Radical-trapping experiments revealed that superoxide anion radicals (O₂^-) and holes (h⁺) were the active species during photocatalytic degradation and that O₂^- was the dominant active species. Therefore, the increased photocatalytic activity of AgBr@Bi₂WO₆/WO₃ was attributed to the atypical double Z-scheme system, which effectively improved the transfer and separation of electron-hole pairs in ternary heterojunction structures.

Keywords: AgBr@Bi(2)WO(6)/WO(3); Double Z-scheme; Ternary heterojunction; Visible light.