Preparation of carbon doped TiO2 thin film as a photocatalyst using a pulsed laser deposition method

• Main Authors: Jhong-Yan Ciou, 邱忠彥
• Other Authors: m.k.wei
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/k463j9

碩士 === 國立東華大學 === 材料科學與工程學系 === 95 === Photocatalysts of carbon doped titanium dioxide films, which were reported to be activated by visible light irradiation as well as ultraviolet irradiation, have been prepared by pulsed laser deposition (PLD) method using TiO2 (99.9% rutile) target in carbon monoxide /oxygen gas mixture. Titanium dioxide thin films were grown either on a lattice-matched LaAlO3 (001), silicon (100) or quartz substrate in oxygen atmosphere and carbon monoxide/oxygen gas mixture. XRD and Raman were used to analyze crystallinity and structure of the deposited films. SEM was used to observe the surface morphology of the films. The photocatalytic properties were characterized by oxidation of methylene blue in aqueous solution, and by reduction of Ag+ in 0.1 mole/L AgNO3 aqueous solution. All TiO2 films deposited on LaAlO3 (001) composed of pure anatase phase. They also revealed strong preferred orientation. However, TiO2 films deposited on Si (100) composed of pure anatase phase only at low substrate temperatures and high oxygen partial pressures. At high substrate temperatures and low oxygen partial pressures, the films on Si constructed from mixed phase of anatase and rutile. The photocatalytic performance of the deposited films was determined by the reduction of silver ions under UV/Vis irradiation. In general, the films deposited on Si had better catalytic performance than those deposited on LaAlO3. But the films deposited on LaAlO3, at high substrate temperatures and high oxygen partial pressures, had the best catalytic performance. All the structures of the carbon doped TiO2 thin films on three different kinds of substrates changed from anatase to rutile as the flow rate of carbon monoxide increased. In addition, the band gap of the deposited decreased with increasing the flow rate of carbon monoxide. For the reduction of Ag+ ions under the illumination of visible light, the carbon doped TiO2 on quartz (CO: 10 sccm) had the best catalytic performance.