The effect of heat treatment on the anatase-rutile phase transformation and photocatalytic activity of Sn-doped TiO2 nanomaterials

Sn-doped TiO2 nanomaterials with different amounts of Sn (1, 2.5, 5, 10, and 15 at%) were prepared by a sol-gel method and characterized by XRD, TG, DTA, EDS, XPS, DRS, SEM, BET, and PL. The photocatalytic activity of the prepared samples was investigated by measuring the degradation of rhodamine B in aqueous solution under UV light. The experimental results indicate that doping with Sn promotes phase transformation from anatase to rutile. The photocatalytic activity of TiO2 is influenced by both the heat treatment temperature and the Sn doping concentration. 1% Sn-TiO2 exhibits the highest degradation rate at 350 degrees C and 5% Sn-TiO2 exhibits the best photocatalytic activity at 500 degrees C and 650 degrees C. The enhancement of the photocatalytic activity can be ascribed to a larger surface area and a better hydration ability, as well as less recombination of the photogenerated pairs.