磁控溅射制备Ag/TiO2复合薄膜的光催化降解性能

为了提高TiO2薄膜的光催化效率,利用中频交流磁控溅射技术,采用Ti和Ag金属靶制备了Ag/TiO2复合薄膜.利用X射线光电子能谱、 X射线衍射和扫描电子显微镜分析了复合薄膜的成分、结构和表面形貌,并研究了其光催化降解性能.结果发现: Ag在厚度较薄时以聚集颗粒形式存在; 在Ag膜厚度为15 nm时, Ag/TiO2复合薄膜与TiO2薄膜相比其光催化效率可提高2倍; Ag/TiO2复合薄膜对亚甲基蓝的光催化降解效率与复合薄膜的透射率均随Ag膜厚度增加逐渐下降,其原因是Ag膜厚度不断增加,最终完全覆盖TiO2薄膜表面,阻挡了TiO2薄膜与污染物的有效接触, Ag作为光生电子捕获剂的有利影响消失.

Photocatalytic degradation properties of Ag/TiO2 composite films prepared by magnetron sputtering

Ag/TiO2 composite films were successfully prepared using a mid-frequency AC magnetron sputtering technique with pure Ti and Ag targets to increase photocatalytic efficiencies of TiO2 films. X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction were used to examine the compositions, surface morphologies, and microstructures of the Ag/TiO2 composite films. The photocatalytic degradation of the Ag/TiO2 composite films was investigated using methylene blue (MB) as the degradation objective. The results show that the Ag film is composed of separate Ag particles when its thickness is lower than 15 nm. Because Ag is an effective capturer of photo-induced electrons, the photocatalytic degradation rate of the Ag/TiO2 composite film is three times the degradation rate of a TiO2 film with the same parameters. The photocatalytic degradation rate and transmittance of the Ag/TiO2 composite film decrease with increasing Ag film thickness since the thicker Ag films cover the entire TiO2 film surface. The Ag film will then prevent contact between the TiO2 film and the MB solution.