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Thickness dependent activity of nanostructured TiO2/α- Fe2O3 photocatalyst thin films

Akhavan, O ; Sharif University of Technology | 2010

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  1. Type of Document: Article
  2. DOI: 10.1016/j.apsusc.2010.09.005
  3. Publisher: 2010
  4. Abstract:
  5. The effect of thickness of TiO2 coating on synergistic photocatalytic activity of TiO2 (anatase)/α-Fe 2O3/glass thin films as photocatalysts for degradation of Escherichia coli bacteria in a low-concentration H2O2 solution and under visible light irradiation was investigated. Nanograined α-Fe2O3 films with optical band-gap of 2.06 eV were fabricated by post-annealing of thermal evaporated iron oxide thin films at 400 °C in air. Increase in thickness of the Fe2O3 thin film (here, up to 200 nm) resulted in a slight reduction of the optical band-gap energy and an increase in the photoinactivation of the bacteria. Sol-gel TiO2 coatings were deposited on the α-Fe2O 3 (200 nm)/glass films, and then, they were annealed at 400 °C in air for crystallization of the TiO2 and formation of TiO 2/Fe2O3 heterojunction. For the TiO2 coatings with thicknesses ≤50 nm, the antibacterial activity of the TiO 2/α-Fe2O3 (200 nm) was found to be better than the activity of the bare α-Fe2O3 film. The optimum thickness of the TiO2 coating was found to be 10 nm, resulting in about 70 and 250% improvement in visible light photo-induced antibacterial activity of the TiO2/α-Fe2O 3 thin film as compared to the corresponding activity of the bare α-Fe2O3 and TiO2 thin films, respectively. The improvement in the photoinactivation of bacteria on surface of TiO2/α-Fe2O3 was assigned to formation of Ti-O-Fe bond at the interface
  6. Keywords:
  7. Antibacterial property ; Iron oxide ; Titania ; Anti-bacterial activity ; Antibacterial properties ; Escherichia coli bacteria ; Glass films ; Glass thin films ; Iron oxide thin films ; Low concentrations ; Nano grains ; Nanostructured TiO ; Optimum thickness ; Photo-induced ; Photocatalytic activities ; Photoinactivation ; Post annealing ; Sol-gel TiO ; TiO ; Titania ; Visible light ; Visible-light irradiation ; Bacteriology ; Coatings ; Escherichia coli ; Glass ; Heterojunctions ; Iron oxides ; Oxide films ; Photocatalysts ; Thin films ; Titanium dioxide ; Vapor deposition ; Optical films
  8. Source: Applied Surface Science ; Volume 257, Issue 5 , 2010 , Pages 1724-1728 ; 01694332 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0169433210012237