Preparation of Sm-loaded brookite TiO2 photocatalysts

Pure and Sm-loaded brookite nanoparticles and thin films were prepd. using TiCl4 as precursor of TiO2. The samples were characterized by X-ray diffraction (XRD), sp. surface area (SSA) detn., diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) measurements. The photocatalytic activity of the powders was investigated by employing the photodegrdn. of 4-nitrophenol in a liq.-solid system while the photoreactivity of the films was tested by evaluating the rate of degrdn. of 2-propanol in a gas-solid system. Loading with Sm resulted in a significant improvement of the photoreactivity of brookite and the beneficial effect was attributed to an increased sepn. efficiency of the photogenerated electron-hole pairs. The content of samarium was an important factor affecting the photocatalytic activity. The optimum amt. of samarium was 1% for the powders and 0.1% for the films. There is a relationship between PL spectra and photoactivity, namely, the lower the PL intensity, the higher the photocatalytic activity.