Effhect Of Te Heat Treatment On The Microstructure And Photocatalytic Activity Of The TiO₂Thin Films

Titanium dioxide （TiO₂） has been extensively investigated in the past decades dueto its excellent electric, optical and catalytic properties, chemical stability andnon-toxicity. The performance for a given application depends strongly on the structure,morphology, grain size and specific surface area. And heat treatment is a simple andeffective method to improve the crystalline and microstructure of TiO₂films. Asystematic study of the effect of the heat treatment temperature on crystalline structure,morphology, and photocatalytic activity of the TiO₂thin films is important.The TiO₂thin films were prepared on high purity silica substrates using DCreactive magnetron sputtering method and by heat treatment at different temperatures.X-ray diffraction （XRD）, Atomic force microscope （AFM）, ultraviolet-visiblespectrophotometry （UV-vis） and transmission electron microscope （TEM） were used tocharacterize the structure and morphology of the TiO₂thin films. And the effect of heattreatment on the structure and photocatalytic activity of the TiO₂thin films is discussed.The results showed that heat treatment have a great influence on the microstructure andphotocatalytic activity of the TiO₂thin films. With increasing heat treatmenttemperature, the films structure changed from amorphous to crystalline anatase and thecrystallization of anatase has improved gradually. At500°C, the TiO₂thin film showedthe highest photocatalytic activity. When the heat treatment temperature increased to600°C, the photocatalytic activity of thin film decreased, which is owing to theformation of rutile phase and growth of TiO₂crystallites resulting in the decrease ofsurface area.