The Photocatalytic Activity of Nano-TiO2 (anatase) Gradient Coating on Tourmaline Beads

Gradient nano-TiO2(anatase) /tourmaline beads were prepared by sol impregnated method, and the phase composition and microstructure of gradient coating were characterized by XRD and SEM, and the photocatalytic activity were evaluated by degradation of methyl orange(MO), compared with that of pure nano-TiO2 (anatase), tourmaline beads. The result indicated that the MO degradation ratio by tourmaline beads is 5.8%; that by pure nano-TiO2 (anatase) is 38.2%; while the MO degradation ratio approached 70.4% by gradient nano-TiO2 (anatase) /tourmaline beads, much better than the other two types of catalysts. When the gradient nano-TiO2 (anatase) /tourmaline beads are illuminated by UV irradiation, the electron-hole pairs are generated and the photogenerated carrier will be adsorbed tightly on the anode of tourmaline, owing to its strong electrostatic field, which suppresses the recombination of the electron-hole pairs, and enhances photocatalytic efficiency.