Hydrophilic property of SiO2-TiO2overlayer films andTiO2/SiO2mixing films①
来源期刊:中国有色金属学报(英文版)2004年第2期
论文作者:关凯书 徐宏 吕宝君
文章页码:251 - 254
Key words:TiO2; SiO2; super-hydrophilic property; overlayer films; sol-gel method
Abstract: The photo-induced hydrophilicity of SiO2overlayer on TiO2films prepared by sol-gel method was investigated by means of soak angle measurement, XPS, UV-VIS and FTIR spectra. The results show that, compared with the TiO2 film without SiO2overlayer, when the TiO2film is thoroughly covered by SiO2overlayer, the hydrophilicity and the sustained effect are enhanced. It is found that the significant growth of the OH-group occurs in the surface of SiO2overlayer. The different mechanism of enhanced hydrophilicity between SiO2 overlayer on TiO2films and TiO2/ SiO2mixing films was analyzed. The result suggests that the photo-generated electrons created in the interface between TiO2 and SiO2 tendto reduce the Ti(Ⅳ) cation to the Ti(Ⅲ) state, and the photogenerated holes transmit through the SiO2 layer to upper most surface efficiently. Once the holes go up to the surface, they tend to make the surface hydrophilic. The stable hydrophilicity of SiO2 overlayer which adsorbs more stable OH groups, enhances the sustained effect, i.e. the super-hy drophilic state can be maintained for a long time in dark place.