Photocatalytic activity of FeTiO3/TiO2/PbS heterojunctions
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Date
2015
Authors
Malkanthi, U. D. R.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
The photocatalytic activities of FeTio₃ /Tio₂ /PbS heterojunctions under , ultraviolet irradiation were investigated for the degradation of methylene blue and rhodamine B. The effects of temperature with different combinations of FeTio₃ /Tio₂ /PbS on the degradation efficiencies were investigated. Catalyst coated (35x 6Qx3 mm) sized glass plates were irradiated with broadband UV light while they were dipped in 150 ml of methylene blue aqueous solutions and 150 ml of rhodamine B aqueous solutions under constant (50 rpm) stirring. Catalyst coated glass plates were prepared by applying wetted catalysts, using distilled water or methanol over the glass plates uniformly and then sintered at 750°C for 3 hours. Heterojunctions of catalysts were also prepared by same procedure such that catalysts are coated over one another. Photocatalyst Tio₂ shows the highest activity among FeTio₃, PbS, and Tio₂ surfaces investigated. There was no considerable effect of the temperature on the degradation of methylene blue or rhodamine B neither with any of catalyst or with heterojunctions. The degradation rate of methylene blue showed a highest value for FeTio₃ /Tio₂ surface. However, when Tio₂ was combined with other catalysts i.e.FeTio₃ and/or PbS, it was observed that the methylene blue degradation rate was declining. Photocatalyst PbS alone showed a higher degradation rate than FeTio₃ while photocatalyst PbS was combined with other catalysts i.e. FeTio₃ and or Tio₂ , it was observed that the methylene blue degradation rate was declining. The degradation rate of rhodamine B showed a highest value for Tio₂ /PbS surface . However, when Tio₂ was combined with other catalysts i.e. FeTio₃ and/or PbS, it was observed that the rhodamine B degradation rate was declining . Photocatalyst PbS alone not showed a more higher degradation rate than FeTio₃ while photocatalyst PbS was combined with other catalysts i.e. FeTio₃ and FeTio₃ /Tio₂ both combination shows same degradation rate with the little bit lower than the highest value for rhodamine B. The results revealed that the optimum photocatalytic oxidation conditions of two dyes are as, methylene blue: Temperature ~50 °c, and FeTio₃ /Tio₂ heterojunction under UV .irradiation and rhodamine B: Temperature ~50 °c, and Tio₂ /PbS heterojunction under UV irradiation.
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Keywords
Photocatalytic activity , Ilmenite , Titanium dioxide , Lead sulfide , FeTiO3 , TiO2 , PbS