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An Investigation on Photocatalytic Behavior of Heavily Doped Titania

Hoseinian, Farideh | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45809 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Nemati, Ali
  7. Abstract:
  8. TiO2 has been considered the most promising photocatalyst for the degradation of pollutants in air or water; however, it shows poor absorption of visible light and requires ultraviolet (UV) light for activation. We have successfully synthesized a visible-light-active carbon and nitrogen and yttrium tridoped TiO2 catalyst. In this study, Nanocrystalline photocatalysts of TiO2 doped with yttrium, codoped with carbon and nitrogen and tridoped with carbon and nitrogen and yttrium were prepared by the sol–gel method and investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy ( DRS), Scanning electron microscopy (SEM/EDS) and Fouriertransform infrared spectroscopy (FT-IR). The photocatalytic activities of the samples were evaluated by monitoring the degradation of methyl orange (MO) solution.Effect of HMT dosage on the photoactivity of CN-TiO2 was investigated. The carbon and nitrogen codoping could create the intragap localized states located above the valence band of TiO2, and carbonate species formed on the TiO2 surface could serve as photosensitizer, and yttrium doping could reduce band gap, enhance visible light absorption and improve separation of electron-hole pairs. The tridoped sample with 8 at.% N, 0.4 at.% Y and 1.5 at.% C exhibited an enhanced photocatalytic efficiency. According to XRD results,it was obvious that 100% anatase phase was formed in the all doped and undoped samples. After 100 min of irradiation with UV, 87% of MO was removed by N-C-Y tridoped sample, which exhibited low band gap (2.56 eV). It is suggested that the charge trapping due to the Y doping and the visible light response due to the N and C codoping are responsible for the enhanced photocatalytic performance in this sample
  9. Keywords:
  10. Photocatalyst ; Yttrium ; Sol-Gel Method ; Carbon and Nitrigen Doped Titanium Dioxide ; Carbon and Nitrogen and Yttrium Doped Titanium Dioxide ; Hexamethylenetetramin ; Methyl Orange

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