多孔TiO2光催化纳米薄膜的制备和微观结构研究

锐钛矿型多孔ＴｉＯ_２纳米薄膜可以从含聚乙二醇（ＰＥＧ）的钛酸盐溶胶前驱体中通过溶胶-凝胶法制备．涂层的形貌，如孔的大小和孔的分布可以通过聚乙二醇的加入量和分子量来控制．当聚乙二醇的加入量和分子量越大，聚乙二醇热分解后在薄膜中产生的气孔就越多和孔径越大．随着ＴｉＯ_２薄膜中气孔孔径和数量的增加，光的散射增强，薄膜的透光率减小．通过扫描电镜（ＳＥＭ）和重量法测定了薄膜的厚度，每镀一次薄膜的厚度增加约为０．０８μｍ．通过Ｘ射线光电子能谱（ＸＰＳ）和红外光谱（ＩＲ）确定了多孔ＴｉＯ_２纳米薄膜中元素的化学组成和表面羟基含量．实验结果表明：薄膜中除含有Ｔｉ、Ｏ元素外，还有一定量来自有机前驱物中未完全燃烧的碳和少量从玻璃表面扩散到薄膜中的Ｎａ和Ｃａ元素；同时发现薄膜表面的羟基含量随聚乙二醇的加入量的增加而增加

Preparation and Microstructure of the Porous TiO2 Nanometer Thin Films by Sol-Gel Method

The porous TiO2 anatase nanometer thin films were prepared from alkoxide solutions containing polyethylene glycol (PEG) by sol-gel method. The effects of PEG addition to the precursor solution on the microstructure of the resultant thin films were studied. The larger amount and the larger molecular weight of PEG, the larger size and more pores produce in the resultant films on the decomposition of PEG during heat-treatment. However, the transmittance of the films decreases due to the light scattering by the larger size and more pores. The film thickness was measured by SEM and weight method, and the thickness of TiO2 films prepared by 1 cycle (from dipping to teat-treatment at 500C1h ) was 0.08μm or so. The chemical composition and The adsorbed hydroxyl content of the films were analyzed with X-ray photoelectron spectroscopy(XPS) and IR spectra. Experiment results show that in the film, besides Ti and O elements, there are a certain amount of residual carbon from the starting organometallic components and a small amount of sodium and calcium ions diffused from the glass substrates. The adsorbed hydroxyl content of such porous thin films increases due to the larger size and more pores in the films.