Preparation and Characterization of Transparent Hydrophilic Photocatalytic TiO2/SiO2 Thin Films on Polycarbonate
Preparation and Characterization of Transparent Hydrophilic Photocatalytic TiO2/SiO2 Thin Films on Polycarbonate
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DOI：
10.1021/la400191x
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发表时间：
2013-03-19
期刊：
影响因子：
3.9
通讯作者：
Bahnemann, Detlef
中科院分区：
文献类型：
--
作者：
Fateh, Razan;Dillert, Ralf;Bahnemann, Detlef
透明亲水TiO2光催化涂层已被广泛应用于赋予表面自清洁性能。复合金属氧化物(二氧化钛/二氧化硅)可以提高光催化性能，改善表面吸附能力，增加表面羟基的数量。本文系统地研究了在二氧化钛薄膜中添加二氧化硅对薄膜的润湿性、光催化活性、结合强度和机械稳定性的影响。采用透明亲水的光催化二氧化钛/二氧化硅薄膜对聚碳酸酯(PC)基片进行包覆，并在其表面预涂一层二氧化硅中间层。采用块状二氧化钛粉末(Sachtleben Hombikat UV100)和不同摩尔比的正硅酸乙酯在酸性乙醇中制备了二氧化钛/二氧化硅薄膜。采用浸渍镀膜法将薄膜沉积到聚碳酸酯基片上。采用紫外可见光谱、红外光谱、椭偏仪、比表面积、原子力显微镜、X射线衍射仪和水接触角等测试手段对薄膜进行了表征。考察了其机械稳定性和抗紫外线性能。通过对亚甲基蓝光降解的动力学分析，计算了涂层表面的光催化活性，并与Pilkington Activ平板玻璃的光催化活性进行了比较。涂层表面在紫外光照射下表现出较高的光催化活性和超亲水性。二氧化硅的加入提高了二氧化钛薄膜的光催化活性，当二氧化钛/二氧化硅的摩尔比为1：0.9时，光催化活性最高。所制备的薄膜对UV(A)辐射具有良好的稳定性。
Transparent hydrophilic photocatalytic TiO2 coatings have been widely applied to endow the surfaces self-cleaning properties. A mixed metal oxide (TiO2/SiO2) can enhance the photocatalytic performance improving the ability of surface adsorption and increasing the amount of hydroxyl surface groups. The present work introduces a systematic study concerning the effect of the SiO2 addition to TiO2 films on the wettability, the photocatalytic activity, the adhesion strength, and the mechanical stability of the films. Transparent hydrophilic photocatalytic TiO2/SiO2 thin films were used to coat the polycarbonate (PC) substrate which was precoated by an intermediate SiO2 layer. The TiO2/SiO2 thin film was prepared employing a bulk TiO2 powder (Sachtleben Hombikat UV 100) and different molar ratios of tetraethoxysilane in acidic ethanol. A dip-coating process was used to deposit the films onto the polycarbonate substrate. The films were characterized by UV/vis spectrophotometry, FTIR spectroscopy, ellipsometry, BET, AFM, XRD, and water contact angle measurements. The mechanical stability and the UV resistance were examined. The photocatalytic activity of the coated surface was calculated from the kinetic analysis of methylene blue photodegradation measurements and compared with the photocatalytic activity of Pilkington Activ sheet glass. The coated surfaces displayed considerable photocatalytic activity and superhydrophilicity after exposure to UV light. The addition of SiO2 results in an improvement of the photocatalytic activity of the TiO2 film reaching the highest value at molar ratio TiO2/SiO2 equal to 1:0.9. The prepared films exhibit a good stability against UV(A) irradiation.