Visible Light Photocatalytic Activities of TiO2 Nanocrystals Doped with Upconversion Luminescence Agent

In order to enlarge the utilization ratio of the visible light, nanometer TiO2 photocatalysts doped with Er3+:Y3Al5O12 (Er3+:YAG) upconversion luminescence agent were synthesized. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, and ultraviolet−visible absorption spectra. The visible light photocatalytic activities of the samples were studied by photodegradation of methylene blue while considering the influences of the dopant concentration, calcination temperature, initial concentration of methylene blue, and catalyst amount. The results showed that the degradation rate in the presence of the doped sample was 2 times that of the undoped one. The photocatalytic mechanics of the degradation reaction was investigated. The results showed that primarily the oxidation mechanics of the photoproduction holes occurred, and the methylene blue was degraded thoroughly in the presence of the doped samples. All the results proved that the doped TiO2 had more excellent photocatalytic activities than the undoped one, and this method can be envisaged as a technology for treating dye wastewater using solar irradiation.