Tetragonal/orthorhombic-bismuth tungstate homojunction formed through in situ bismuth induced phase transformation as highly efficient photocatalyst for pollutant degradation

Chun Chang; Li Kan; Weina Mu; Qiong Wang; Shih-Yuan Lu

doi:10.1016/j.jcis.2021.08.167

Tetragonal/orthorhombic-bismuth tungstate homojunction formed through in situ bismuth induced phase transformation as highly efficient photocatalyst for pollutant degradation

J Colloid Interface Sci. 2022 Feb;607(Pt 1):269-280. doi: 10.1016/j.jcis.2021.08.167. Epub 2021 Aug 30.

Authors

Chun Chang¹, Li Kan², Weina Mu², Qiong Wang³, Shih-Yuan Lu⁴

Affiliations

¹ College of Chemistry and Materials Engineering, Bohai University, Jinzhou 121013, China; Institute of Ocean Research, Bohai University, Jinzhou 121013, China. Electronic address: cchang2019@bhu.edu.cn.
² College of Chemistry and Materials Engineering, Bohai University, Jinzhou 121013, China.
³ College of Chemistry and Materials Engineering, Bohai University, Jinzhou 121013, China; Institute of Ocean Research, Bohai University, Jinzhou 121013, China.
⁴ Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan. Electronic address: sylu@mx.nthu.edu.tw.

PMID: 34506999
DOI: 10.1016/j.jcis.2021.08.167

Abstract

Tetragonal/orthorhombic-bismuth tungstate (t/o-Bi₂WO₆) homojunctions of high photocatalytic efficiencies were fabricated through a novel in situ Bi induced phase transformation. The photocatalytic efficiencies of t-Bi₂WO₆ were greatly enhanced via formation of the homojunction. Photocatalytic degradation of rhodamine B (RhB), a recalcitrant organic pollutant, under simulated sunlight illumination was investigated as a demonstration for the efficiency enhancement. A 6.22 folds improvement was achieved with formation of the homojunction in terms of reaction rate constants. The homojunction catalyst was demonstrated to be photocatalytically stable over a five cycles operation. The t/o-Bi₂WO₆ homojunction enhances separation and utilization efficiency of photo-generated charge carriers and thus greatly boosts the catalytic efficiency. Trapping tests and electron spin resonance spectroscopy were conducted to reveal that singlet oxygen (¹O₂), hole (h⁺), electrons (e^-), and superoxide anion radical (O₂^-) are the main working reactive species for RhB degradation. Density functional theory (DFT) calculations were performed to prove the feasibility of Bi induced phase transformation of t-Bi₂WO₆ to o-Bi₂WO₆. The present development offers a new design route for high efficiency photocatalysts for water pollution control.

Keywords: Bi(2)WO(6); Bismuth inducement; Homojunction; In situ construction; Phase transformation.

MeSH terms

Bismuth
Environmental Pollutants*
Light
Tungsten Compounds*

Substances

Environmental Pollutants
Tungsten Compounds
tungstate
Bismuth