| 초록 |
Visible light photocatalyst composites of NaYF4:(Yb, Er)-CuO were synthesized by mechanical milling and coated with TiO2-sol. X-ray diffraction (XRD) analysis confirmed the presence of nano-crystalline TiO2, CuO and NaYF4:(Yb, Er) phosphor phases. Diffuse reflectance spectrum (DRS) of the multi-composite powders showed an estimated band gap of 2.5 eV for the NaYF4:(Yb, Er)-CuO/TiO2 phosphor. The visible light (λ＞410 nm) degradation of MB-H2O2 solutions mixed with photocatalyst composites was almost 100% within 3 hours. TiO2-sol gel coated NaYF4:(Yb, Er)-CuO multi-composites showed better photocatalytic performance when compared to NaYF4:(Yb, Er)-CuO composites. The multi-composites which exist at the interfaces of NaYF4:(Yb, Er)-CuO/TiO2 powders enhance energy bending in the photocatalyst, hence improved visible light absorption. The visible light photocatalytic properties of NaYF4:(Yb, Er)-CuO/TiO2 composites are applicable for pollution alleviation in waste water treatment plants.Visible light photocatalyst composites of NaYF4:(Yb, Er)-CuO were synthesized by mechanical milling and coated with TiO2-sol. X-ray diffraction (XRD) analysis confirmed the presence of nano-crystalline TiO2, CuO and NaYF4:(Yb, Er) phosphor phases. Diffuse reflectance spectrum (DRS) of the multi-composite powders showed an estimated band gap of 2.5 eV for the NaYF4:(Yb, Er)-CuO/TiO2 phosphor. The visible light (λ＞410 nm) degradation of MB-H2O2 solutions mixed with photocatalyst composites was almost 100% within 3 hours. TiO2-sol gel coated NaYF4:(Yb, Er)-CuO multi-composites showed better photocatalytic performance when compared to NaYF4:(Yb, Er)-CuO composites. The multi-composites which exist at the interfaces of NaYF4:(Yb, Er)-CuO/TiO2 powders enhance energy bending in the photocatalyst, hence improved visible light absorption. The visible light photocatalytic properties of NaYF4:(Yb, Er)-CuO/TiO2 composites are applicable for pollution alleviation in waste water treatment plants. |
