不同金属离子掺杂TiO2薄膜的制备及光催化活性的研究

以溶胶-凝胶法制备了分别用Ag^+、Cu²⁺、Fe³⁺、La³⁺、Ce³⁺和Eu³⁺等离子掺杂的纳米TiO₂薄膜，经XRD和UV-Vis对薄膜样品进行表征并研究了其光催化活性。XRD结果证明，掺镧TiO₂薄膜与未掺杂薄膜的X射线衍射图基本一致，实验条件下主要为锐钛矿型，且掺入La^3+离子使得TiO₂薄膜的晶粒变小。UV-Vis吸收光谱说明当λ＞380 nm时，其吸光度低于0.15。薄膜光催化降解亚甲基蓝的实验表明,La³⁺或Fe^3+掺杂薄膜的光催化降解率远高于未掺杂TiO₂薄膜，而Ce^3+或Cu^2+离子掺杂薄膜与未掺杂薄膜的光催化活性相似，掺Ag⁺或Eu³⁺离子则降低了活性。当最佳掺杂量La³⁺为0.6%或Fe³⁺为1.5%时，光催化降解率分别高达92%和82%。

Preparation and photocatalytic properties of TiO2 thin films doped with various metal ions

Nanocrystalline titania (TiO2) thin films doped respectively with Ag^+,Cu²⁺,Fe³⁺,La³⁺,Ce³⁺ and Eu³⁺ were prepared by sol-gel method and characterized by means of XRD and UV-Vis. Activity of the as-prepared photocatalysts was tested. No much difference was observed between La³⁺-doped TiO₂ thin films and non-doped TiO₂ thin films, with crystalline structure of anatase; doping of La³⁺ reduced particle diameter of TiO₂ thin films. UV-Vis results showed that absorbence of the thin films is less than 0.1 when λ＞380 nm. Photocatalytic degradation of methylene blue over titania thin films showed that photocatalytic degradation rate over La^3- or Fe³⁺-doped thin films was much higher than non-doped titania thin films; photocatalytic activity of Ce³⁺- or Cu²⁺-doped titania thin films is similar to that of non-doped titania thin films; activity of the Ag⁺- or Eu³⁺-doped titania thin films was lower than non-doped titania thin films. Optimum amount of doped La³⁺ and Fe³⁺ was 0.6% and 1.5%, with photocatalytic degradation rate of 92% and 82%, respectively.