Enhanced Photodecomposition Performance of (TiO₂-CeO₂) Composite Supported on Sr₄Al₁₄O₂₅:Eu,Dy Long-Persistent Phosphor

This study prepared a (TiO₂-CeO₂)/Sr₄Al₁₄O₂₅: Eu²⁺,Dy³⁺heterojunction photocatalyst by coating (TiO₂-CeO₂) nanoparticles on a Sr4Al14O25:Eu,Dy phosphor substrate using a hydrothermal reaction method. The fabricated (TiO₂-CeO₂)/Sr₄Al₁₄O₂₅: Eu²⁺,Dy³⁺composites were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV/Vis DRS), Brunauer-Emmett-Teller (BET), and Raman spectroscopy. The photocatalytic performance of the (TiO₂-CeO₂)/Sr₄Al₁₄O₂₅: Eu²⁺,Dy³⁺composites was investigated through the decomposition of toluene gas for various ratios of TiO₂to CeO₂(3:7, 5:5, and 7:3) and heat treatment ranging from 300 to 700 °C. The coupling between (TiO₂-CeO₂) and the highly persistent Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺phosphor reduced the energy band gap and enhanced visible light absorption. In particular, the 5:5 ratio of TiO₂to CeO₂on Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺showed excellent photocatalytic performance, decomposing over 85 % of the toluene gas within 150 min even under visible-light irradiation. The results suggest that the CeO₂particles might increase the specific surface area, and effectively suppress the recombination of electrons and holes generated from TiO₂, thereby enhancing the photocatalytic reactivity.