Preparation of V or W Doped TiO_2 Coating Hollow Glass Spheres and Photocatalytic Characterization

摘要

To improve the photocatalytic activity of TiO_2 coated hollow volcanic glass spheres, vanadium or tungsten hydroxide was doped on the surface of volcanic glass in the aqueous solution of NH_4VO_3 or 5(NH_4)_2O centre dot 12WO_3 centre dot 5H_2O. The volcanic glass was ballooned by heat treatment in temperature ranges of 960 approx 1,000 deg C, and these hydroxides were translated into metallic oxides in this process.On increasing the vanadium loading, the crystal size of anatase TiO_2 on the surface of volcanic glass spheres increased and the phase transformation of anatase to rutile occurred. As the result, the removal rate of NO gas was decreased. Whereas, when the tungsten was doped, there was not almost the change of the crystal size of anatase TiO_2 and the phase transformation of anatase to rutile was not observed. The crystal size of anatase TiO_2 appeared about 12nm and the removal rate of NO gas increased with raising the tungsten loading. The maximum removal rate of NO gas was observed with adding the tungsten of 0.54 wt percent.