Effects of fluorination and thermal shock on the photocatalytic activity of Bi2O3 nanopowders


BOUZIANI A., Park J., ÖZTÜRK A.

Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol.626, 2021 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 626
  • Publication Date: 2021
  • Doi Number: 10.1016/j.colsurfa.2021.127049
  • Journal Name: Colloids and Surfaces A: Physicochemical and Engineering Aspects
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC
  • Keywords: Bi2O3, Fluorination, Thermal shock, Photocatalysis, Nanopowder, NITROGEN-DOPED TIO2, SURFACE FLUORINATION, DEGRADATION, NANOPARTICLES, PERFORMANCE, NH4F

Abstract

© 2021 Elsevier B.V.Fluorinated Bi2O3 (F-Bi2O3) nanopowder was prepared via fluorination followed by thermal shock of α-Bi2O3 nanopowder. The XRD, FTIR, SEM, and DRS characterization techniques were employed to investigate the effects of fluorine (F) insertion into the α-Bi2O3 host and the thermal shock from different temperatures. The crystal structure, optical and photocatalytic properties of the F-Bi2O3 nanopowders prepared were researched. The XRD results confirmed the substitution of O2- with F-. The FTIR results revealed that the coordination of Bi atoms changed upon F- substitution. The incorporation of F into the α-Bi2O3 host and thermal shock did not influence the morphology but modified the band structure of α-Bi2O3, leading to a red-shift in the optical absorption edge. Also, the bandgap narrowed from 2.8 eV to 2.6 eV. The density functional theory calculation proved that the F 2p orbitals were positioned in the valence band (VB), resulting in broader and more spread bands for F-Bi2O3. The results suggested that the photoexcited charge carrier mobility in the valence band (VB) and conduction band (CB) are enhanced upon F insertion into α-Bi2O3. The photocatalytic efficiency of the synthesized nanopowders was assessed by the degradation of Bromocresol Green (BG) under visible light illumination. Photocatalytic activity improved upon fluorination. The F-Bi2O3 nanopowders thermally shocked from higher temperatures showed negligible photocatalytic performance. The best photocatalytic performance of 70% BG degradation was realized after 180 min visible irradiation for the F-Bi2O3 nanopowder thermal shocked from 500 °C.