Rapid synthesis of BiOBrxI1-x photocatalysts: insights to the visible-light photocatalytic activity and strong deviation from Vegard’s Law

Liang Kong, Junqiu Guo, Joshua W. Makepeace, Tiancun Xiao, Heather F. Greer, Wuzong Zhou, Zheng Jiang, Peter P. Edwards

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

A series of visible-light-responsive BiOBrxI1-x solid solutions were prepared by a rapid and efficient ultrasonication synthesis and applied in photodegradation of Rhodamine B in aqueous solution. The detailed characterisations showed that the lattice parameters and their band structures of the BiOBrxI1-x solid solutions significantly deviated from the well-established Vegard’s law for solid solution materials. The Mulliken electronegativity and valence band XPS analyses revealed that the substitution of Br by less electronegative iodine can simultaneously modulate the edges of conductance and valence band of the BiOBr, leading to nonlinear dependence of bandgap (Eg) on the halogen anion concentrations. Although the solid solution displayed superior RhB photodegration activity to BiOI, only Br-rich BiOBrxI1-x solid solutions (x>0.5) were more active than BiOBr and BiOI, with the optimal one is BiOBr0.75I0.25. The Br-dependence of bandstructure and photocatalytic activity for the BiOBrxI1-x solid solutions as well as their rate-limiting radical species were also clarified based on experimental and theoretical analyses.
Original languageEnglish
JournalCatalysis Today
VolumeIn press
Early online date11 Feb 2019
DOIs
Publication statusE-pub ahead of print - 11 Feb 2019

Keywords

  • BiOBrxI1-x
  • Solid solution
  • Band edges
  • Visible light photocatalysis

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