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 TiO2 to 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 TiO2 to CeO2 on 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 CeO2 particles might increase the specific surface area, and effectively suppress the recombination of electrons and holes generated from TiO2, thereby enhancing the photocatalytic reactivity.

Abstract
1. 서 론
2. 실험 방법
    2.1. (TiO2-CeO2)/Sr4Al14O25:Eu2+,Dy3+ 혼성 복합소재제조
    2.2. 재료 특성 분석 및 광분해 반응 측정
3. 결과 및 고찰
    3.1. 재료 특성
    3.2. 광촉매 반응 특성
4. 결 론
References
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• 김지현(서울시립대학교 신소재공학과) | Ji-Hyeon Kim (Department of Materials Science and Engineering, University of Seoul, Seoul 02504, Republic of Korea)
• 김정식(서울시립대학교 신소재공학과) | Jung-Sik Kim (Department of Materials Science and Engineering, University of Seoul, Seoul 02504, Republic of Korea) Corresponding author