Abstract:In order to develop the high photocatalytic activity of TiO₂ under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon (SAC) supported photocatalyst doped with upconversion luminescence agent Er³⁺:YAlO₃ was prepared by immobilizing Er³⁺:YAlO₃/TiO₂, which was obtained by combination of Er³⁺:YAlO₃ and TiO₂ using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction (XRD), energy dispersive X-ray spectra (EDS) analysis, scanning electron microscopy (SEM) and fluorescence spectra analysis (FSA). The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange (MO) in aqueous solution under visible light irradiation from a LED lamp (λ>400 nm). The results showed that Er³⁺:YAlO₃ could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er³⁺:YAlO₃/TiO₂ calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min^-1 under visible light irradiation.

Key words: visible light; upconversion luminescence; TiO₂; activated carbon; photocatalysis