Effects of heat treatment on photocatalytic property of sol-gel derived polycrystalline TiO2

Polycrystalline TiO2 in the bulk form was prepared by hydrothermal treatment of amorphous TiO2 gel, and its photocatalytic activity for degradation of ethanol and physical properties were investigated after drying and calcination (300-650 degreesC). The maximum photocatalytic activity reached when the polycrystalline TiO2 was calcinated at temperatures from 300 to 500 degreesC, which was almost the same as for a commercial TiO2 powder. It was markedly reduced above 600 degreesC. Photocatalytic activity of TiO2 was affected by crystal growth of anatase, progress of sintering, anatase-rutile transformation and morphology of the polycrystalline TiO2. It was a characteristic of the polycrystalline TiO2 prepared in this study that the photocatalytic activity did not vary so much with the calcination temperature in the range of 300-500 degreesC.