利用光催化觸媒來分解有機廢棄物是近年來用以處理水質的淨化和工業廢水處理最有潛力的方法。其中二氧化鈦是具有高光催化效率的觸媒之一，雖然二氧化鈦對於分解有機化合物有很大的效果，但在使用它時存在著一些問題，比如說二氧化鈦粉體的回收不易，二氧化鈦觸媒膜的緻密度高透光不易，導致效率降低。我們利用”分子自我組合”的特性，在二氧化鈦膜與載體間插入一個含雙官能基之修飾分子將二者連結，以製造高穩定性和高催化活性的新型二氧化鈦薄膜。本實驗所用的修飾分子一端為矽烷分子，一端是磺酸基(-SO3H)的雙官能基分子，利用矽烷分子連接載體，磺酸基來捕捉二氧化鈦粒子，用這種方式製造的二氧化鈦薄膜可能有比較大的表面積和高的穩定性，經過光催化分解水楊酸之活性測試，得知二氧化鈦粒徑小於200nm時，沈積在修飾過載體上的二氧化鈦膜，其活性比較大；鍛燒觸媒膜會對使觸媒活性降低，但是沈積在修飾載體上的二氧化鈦膜活性降低較少；經摻雜金屬離子 (Au+、Pd2+)，鍍膜液老化或觸媒膜老化，都會使觸媒的光催化活性有明顯的增加，但仍以沈積在修飾載體上的二氧化鈦觸媒膜活性增加較顯著。然而觸媒膜的壽命似乎與所沈積的載體是否修飾無關。 Photocatalytic degradation of organic wastes is commonly used in the purification of water and the industrial wastewater trearment. TiO2 is one of the most efficient photocatalysts. Although TiO2 is powerful in the decomposition of toxic organic compounds, it has some unsolved problems such as the separation of TiO2 powder from reaction media and TiO2 film could be too dense to block the light, therefore decreases the photon catalytic activity. In this study, we use the property of “molecular self-assembly” to prepare new type of TiO2 film with good stability and catalytic activity. The glass substrates for TiO2 deposition were modified with a monolayer of 3-Mercaptopropyl trimethoxysilane. The terminal group of the SAM is a thiol (-SH) functional group which can be oxidized to SO3- by acetic acid and hydrogen peroxide. The sulfonate (-SO3H) functional group was then used to grape TiO2 particles. TiO2 film prepared with this method may have a large surface area and more stable. Photocatalytic decomposition of salicylic acid was used to test the performance of TiO2 catalyst. It was found that when the TiO2 particles was smaller than 200 nm, TiO2 deposited on modified substrate has higher catalytic activity than that deposited on unmodified substrate. Doping TiO2 film with precious metal(such as Au、Pt), aging of TiO2 suspension and TiO2 film will increase the activity of TiO2 catalyst. However TiO2 deposited on modified substrate has more discernible effect. Calcination of TiO2 film decrease its catalyic activity. The decreasing is less obvious when TiO2 film was deposited on modified substrate. Nevertheless, the life-time of TiO2 catalyst did not change when an organic molecule was inserted in-between the catalyst and the substrate.
