Photocatalytic Characteristics For The Nanocrystalline TiO2 Supported On Sr4Al14O25: Eu2+, Dy3+ Phosphor Beads
Advanced Materials Letters,
2016, Volume 7, Issue 1, Pages 36-41
AbstractThe photocatalytic behaviors of TiO2-supported on the long lasting phosphor beads were examined. Nanocrystalline TiO2 was coated on ellipsoidal-spherical beads of an alkaline earth aluminate phosphor, Sr4Al14O25:Eu 2+ , Dy 3+ , by low pressure chemical vapor deposition (LPCVD). The photocatalytic reaction was examined by measuring the decomposition of benzene and toluene gases by gas chromatography under ultraviolet, visible light (λ> 410 nm) irradiation, as well as in the dark. The LPCVD TiO2-coated Sr4Al14O25:Eu 2+ , Dy 3+ showed an active photocatalytic reaction under visible irradiation. The mechanisms of the photocatalytic reactivity for the TiO2-coated Sr4Al14O25:Eu 2+ , Dy 3+ phosphor beads were discussed in terms of the crystal structure at the interface, energy band structure and phosphorescence. The coupling of TiO2 with the Sr4Al14O25:Eu 2+ , Dy 3+ phosphor resulted in energy band bending in the junction region between TiO2 and Sr4Al14O25:Eu 2+ , Dy 3+ phosphor, which makes the TiO2 crystal at the interface photo-reactive under visible light irradiation. The LPCVD TiO2-coated Sr4Al14O25:Eu 2+ , Dy 3+ phosphor beads were also photo-reactive in the dark through the light photons emitted from the Sr4Al14O25:Eu 2+ , Dy 3+ phosphor.
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