Abstract: The tourmaline powders (400 mesh) was either mixed to the sol during sol-gel preparation or with P-25 suspension to coat stainless steel net. The mixed coating on the stainless steel net was calcinated, the supported catalysts surface structure is investigated by X-ray diffraction(XRD),scanning electron microscope (SEM)and transmission electron microscopy,the photo-catalytic activity of the catalysts(on 3 cm?15 cm stainless steel net) was determined by photocatalytic degradation of toluene in air with 20 W germicidal UV lamp in a static reactor(14 L). The effect of the tourmaline powders on the catalyst crystal size during TiO₂ preparation using sol-gel method was studied. The results show that the tourmaline powder is beneficial to the preparation of smaller sized TiO₂ nano-crystal, which in combination with the coherent electric field of tourmaline improved the catalytic activity of the supported catalyst. By using the sol gel prepared T-TiO₂-1 catalyst, about 87% toluene removal was obtained when initial concentration was 180 mg·m^-3, and about 82% toluene removal was obtained when initial concentration was 70 mg·m^-3 after 4 hours reaction. The average activity of composite catalyst film on stainless steel net for toluene removal prepared via sol gel method was 1.90 mg·m^-2·min^-1 or 0.11 mg·g^-1·min^-1, while using the T-TiO₂-2 catalyst, about 58% toluene removal was obtained when initial concentration was 180 mg·m^-3, and about 42% toluene removal was obtained when initial concentration was 70 mg·m^-3 after 4 hours reaction. The average activity of composite catalyst film on stainless steel net for toluene removal prepared via sol gel method was 1.35 mg·m^-2·min^-1 or 0.18 mg·g^-1·min^-1.

Key words: micron-size tourmaline, TiO₂, photocatalysis, toluene