Transformation of amorphous Bi₂O₃ to crystal Bi₂O₂CO₃ on Bi nanospheres surface for photocatalytic NOₓ oxidation: Intensified hot-electron transfer and reactive oxygen species generation

Peng ZHANG, Yongfang RAO, Yu HUANG, Meijuan CHEN, Tingting HUANG, Wing Kei HO, Shuncheng LEE, Junbo ZHONG, Junji CAO

Research output: Contribution to journalArticlespeer-review

Abstract

The inevitable amorphous Bi₂O₃ on the surface of plasmonic Bi nanospheres serving as the recombination center of hot electron-hole pairs, hindered the transfer of photo-generated hot electrons and production of reactive oxygen species (ROS) seriously. In this study, Bi@amorphous Bi₂O₃ was transformed to Bi@crystal Bi₂O₂CO₃ by secondary hydrothermal reaction. Bi@Bi₂O₂CO₃ core–shell photocatalyst exhibited higher visible-light catalytic activity (34.1%) than Bi@Bi₂O₃ did (12.3%) in terms of NOₓ removal. Photoelectrochemical, surface photovoltage spectroscopy spectra and Kelvin probe force microscopy measurement results indicate that Bi₂O₂CO₃ shell reduced the transmission resistance of hot electrons excited from Bi core. O₂⁻TPD, trapping experiments and density functional theory further confirmed that the transferred hot electrons were a help for ROS generation and •O₂⁻ radicals were the major contributor. This study not only addresses the unsettled issue of surface amorphous Bi₂O₃, but also provides a facile method to transform the amorphous shell to crystal phase of core–shell photocatalyst and new insights into the hot electrons separation and the formation of main ROS over the surface crystal transition of plasmonic Bi. Copyright © 2021 Elsevier B.V. All rights reserved.
Original languageEnglish
Article number129814
JournalChemical Engineering Journal
Volume420
Issue numberPt. 1
Early online date24 Apr 2021
DOIs
Publication statusE-pub ahead of print - 24 Apr 2021

Citation

Zhang, P., Rao, Y., Huang, Y., Chen, M., Huang, T., Ho, W., . . . Cao, J. (2021). Transformation of amorphous Bi₂O₃ to crystal Bi₂O₂CO₃ on Bi nanospheres surface for photocatalytic NOₓ oxidation: Intensified hot-electron transfer and reactive oxygen species generation. Chemical Engineering Journal, 420(Pt. 1). Retrieved from https://doi.org/10.1016/j.cej.2021.129814

Keywords

  • Hot electron transfer
  • Crystal transformation
  • O₂⁻ radicals
  • Bi@B₂O₂CO₃
  • Photocatalytic oxidation NOₓ

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