Microemulsion synthesis of ms/tz-BiVO4 composites: The effect of pH on crystal structure and photocatalytic performance

Xinqiang Cao, Yan Gu, Hailin Tian, Yanfen Fang, David Johnson, Zhiyong Ren, Chuncheng Chen, Yingping Huang

Research output: Contribution to journalArticle

Abstract

In this work, BiVO4 composites, containing the tetragonal zircon phase (tz-BiVO4), and monoclinic scheelite phase (ms-BiVO4), were synthesized using the microemulsion method. The effect of pH on phase composition and photocatalytic activity were investigated. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), a ms/tz-BiVO4 composite forms at pH = 1.0 and pure ms-BiVO4 is obtained in the pH range 4.0–10.0. The three primary steps in preparing BiVO4 were monitored by optical microscopy and the role played by the microemulsion on the phase composition of BiVO4 is explained. Photoluminescence spectroscopy (PL), UV–visible diffuse reflectance spectroscopy (UV-DRS), Brunauer-Emmett-Teller (BET), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the physical and chemical properties of BiVO4 composites. The composite formed at pH = 1 exhibited the lowest hole-electron (h+-e-) recombination rate, resulting in the highest photocatalytic activity towards microcystin-LR (MC-LR), with near 100% removal of MC-LR in 5 h. ESR and trapping experiments indicated that MC-LR degradation was mediated primarily by hydroxyl radicals (•OH), superoxide radicals (O2•−) and photogenerated holes (h+).

Original languageEnglish (US)
Pages (from-to)20788-20797
Number of pages10
JournalCeramics International
Volume46
Issue number13
DOIs
StatePublished - Sep 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Process Chemistry and Technology

Keywords

  • Effect of pH on phase composition
  • Hole-electron recombination
  • Microcystin-LR
  • Microemulsion synthesis
  • ms/tz-BiVO composites

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