射频磁控溅射制备纳米TiO2薄膜的光电化学行为

在室温下采用射频磁控溅射法制备了纳米晶粒的TiO2薄膜,用循环伏安法研究了ITO/TiO2薄膜电极的光电化学行为,并测量了相应TiO2薄膜的亲水性与光催化能力.结果表明,在室温下制备的TiO2薄膜为无定形结构,当退火温度超过400 ℃时转化为锐钛矿结构.在400 ℃下退火的TiO2薄膜具有良好的亲水性和光催化能力. TiO2薄膜电极用254 nm的紫外光照射一定时间后会产生新的氧化峰,且随着光照时间的增加,峰电流也增加.初步认为用紫外光照射一定时间后, TiO2薄膜的循环伏安图的氧化峰属于光生的Ti3＋,而光致亲水性可能与Ti3＋的生成有关.

Photoelectrochemical Characteristics of Nano-Titanium Dioxide Thin Films Prepared by RF Magnetron Sputtering

Nanoscale titanium dioxide thin films were prepared at room temperature by RF magnetron sputtering process and annealed at different temperatures. Electrochemical characteristic of ITO/TiO2 electrode under UV irradiation was investigated using the method of cyclic voltammetry, and photo-induced hydrophilicity and photocatalytic activity of TiO2 thin films have been studied. It shows that the as deposited TiO2 thin films are in amorphous state and the anatase phase forms when anneal temperature is over 400 ℃. New oxidative peaks were observed when the TiO2 electrode was irradiated by 254 nm UV light for a certain time. The peak current increased with the increase of UV irradiation time. The oxidative peaks at 0.1 V and 0.05 V were observed for TiO2 electrode annealed at 300 and 500 ℃,respectively, and both were observed for TiO2 electrode annealed at 400 ℃. It is assumed that the new oxidative peak belongs to the oxidation of Ti3＋, which was formed during the UV illumination, and the changes of hydrophilicity of the films may be related with the formation of Ti3＋ on the surface when the films were irradiated by UV light. The TiO2 thin films annealed at 400 ℃ exhibit a good hydrophilicity and photocatalytic activity.