多孔TiO2薄膜自洁净玻璃的亲水性和光催化活性

亲水性多孔TiO2薄膜自洁净玻璃以含聚乙二醇的钛醇盐溶胶前驱体中通过浸渍提拉法制备;随着前驱物中聚乙二醇加入量的增加, 多孔TiO2薄膜表面的羟基含量也增加, 薄膜表面的亲水性增强, 水与薄膜表面的接触角下降为0°. 该亲水性多孔TiO2薄膜自洁净玻璃具有明显的自洁净和易清洗功能. 紫外-可见光透过光谱分析表明, 随着TiO2薄膜中孔径的增大, 光的散射增强, 透光率减小. 该TiO2镀膜玻璃对于紫外线具有吸收作用. 甲基橙水溶液的光催化降解实验表明, 在TiO2薄膜中引入适当大小的微孔可显著增强薄膜的光催化活性, 但当孔径接近400 nm时, 薄膜的光催化活性减弱.

Hydrophilicity and Photocatalytic Activity of Self-cleaning Porous TiO2 Thin Films on Glass

The porous TiO_2 thin films deposited on glass surface were prepared from alkoxide solutions containing polyethylene glycol(PEG) by a dip-coating technique. The effects of PEG addition to the precursor solution on the photocatalytic activity and hydrophilicity of the resultant thin films were studied. The larger the amount of PEG, the larger the adsorbed hydroxyl content in the as-prepared porous thin films, the better the hydrophilicity. The contact angle between water and the porous TiO_2 thin films declines to zero. The glass with porous TiO_2 thin films possesses self-cleaning function and is easily washed. However, the transmittance of the glass with porous TiO_2 thin films decreases due to the enhancement of light scattering of the larger pores(400 nm). The photocatalytic degradation experiments show that methyl orange aqueous solution was efficiently decolorized in the presence of the porous TiO_2 thin films by illumination with a 125 W high pressure mercury lamp. The photocatalytic activity of the TiO_2 thin films is obviously enhanced by the PEG addition to the precursor solutions. On the other hand, when the amount of PEG reaches 2.0 g, the photocatalytic activity will drop.