The enhancement of adsorption and photocatalytic activity of rare earth ions doped TiO 2 for the degradation of Orange I

Abstract

Rare earth ions (Sm 3+, Nd 3+, Pr 3+) doped TiO 2 (RE 3+–TiO 2) catalysts were prepared by the sol–gel method, and characterized by X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS). The adsorption abilities and photocatalytic activities of RE 3+–TiO 2 were evaluated by isothermal adsorption and Orange I degradation under UV light and visible light illumination. The adsorption results showed that RE 3+–TiO 2 had higher saturated adsorption amounts and higher adsorption equilibrium constants than pure TiO 2. The adsorption equilibrium constants ( K a) and the saturated adsorption amount ( Q max) of RE 3+–TiO 2 would increase with the increase of dosage. In the meantime, the photocatalytic activity of RE 3+–TiO 2 for Orange I degradation under both UV and visible light irradiations were higher than that of TiO 2. The optimal dosage was 1.5% for Orange I degradation under UV light and 1.0% under visible light. The higher photoactivity might be attributable to the transitions of 4f electrons of RE 3+.