Preparation of TiO2: Er3+ Hollow Spheres and Its Photocatalytic Properties

Using tetrabutyl titanate, erbium oxide and nitric acid as raw materials, TiO2: Er3+ hollow spheres were prepared with carbon spheres as template. The structures and morphologies of the obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The photocatalytic activities were studied by degradation of organic pollutants (rhodamine B, methylene blue, alizarin red, methyl orange) using UV-Vis spectrophotometer. The factors, such as Er3+ dopant concentration, pH of the dye solution, on the photocatalytic activities were discussed. The results showed that uniform and well crystallized TiO2: Er3+ hollow spheres in an anatase phase, with diameter of 120 nm could be obtained via carbon-template method followed by a heat treatment at 600 degrees C for 3 h. The specific surface area of the TiO2: Er3+ hollow spheres was about 60.5 m(2)/g. When the Er3+ dopant concentration was 0.5 mol% of Ti4+ ions in TiO2, the photocatalytic activity of catalyst on the methyl orange was better than the other samples. Among the four different organic pollutants, the photocatalytic activity on the alizarin red was best. TiO2: 0.5mol%Er3+ showed the better photocatalytic properties than the undoped TiO2. The photodegradation efficiency of alizarin red with TiO2: 0.5mol%Er3+ was 30% higher than that with the undoped TiO2 under UV light irradiation.