溶胶-凝胶工艺制备TiO_2薄膜的表面组成和价态研究

Study on Surface Composition and Valence State of TiO_2 Thin Film Prepared by Sol\|Gel Technology

通过Ｘ射线光电子能谱（ＸＰＳ）和电子自旋共振谱（ＥＳＲ）， 确定了采用溶胶－凝胶工艺制备的ＴｉＯ２光催化纳米薄膜中元素的化学组成和价态． 实验结果表明， 薄膜中除含有钛和氧元素外，还有一定量的来自有机前驱物中未完全燃烧的残余碳和少量从玻璃表面扩散到薄膜中的钠和钙离子； Ｔｉ除了以Ｔｉ４＋ 价形式存在外， 还有一定量的Ｔｉ以Ｔｉ３＋ 和Ｔｉ２＋ 形式存在． 这种情况主要是由于有机基团的燃烧、来自玻璃基体中钠与钙离子的扩散和热处理工艺等原因造成的． ＴｉＯ２薄膜在５３０ ｎｍ 附近的宽吸收带， 也证实了ＴｉＯ２薄膜中低价钛元素的存在．

The chemical composition and the valence state of the elements in TiO 2 thin films prepared by sol\|gel technology were characterized by X\|ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR). Experimental results show that besides Ti and O elements, there is 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. Although Ti of the oxides mainly exists in Ti(Ⅳ) valence state, there is a certain amount of oxides of Ti(Ⅲ) and Ti(Ⅱ). This phenomenon is discussed in relation to the combustion of organic radicals, the diffusion of sodium and calcium ions from the glass substrates and heat\|treating process. The UV\|visible spectra of the TiO 2 thin films have a wide adsorption band at about 530 nm , which further confirms the existence of a certain amount of oxides of \{Ti(Ⅲ)\} and Ti(Ⅱ) in the TiO 2 thin films.