铁、氮共掺杂二氧化钛粉末的制备及光催化活性

Preparation and Photocatalytic Activity of TiO_2 Powder Codoped with Iron and Nitrogen

由于TiO2具有催化活性高、价廉、耐腐蚀性强、无污染等一系列优点．近年来TiO2光催化技术成为研究热点。但由于TiO2带隙较宽（Eg=3．0-3．2eV），只能被400nm以下紫外光激发．不能充分利用太阳能．且光催化反应效率不高。限制了其现实应用。为了克服这些缺点．延伸TiO2在可见光区的响应，提高光催化反应效率，很多研究者做了TiO2的改性研究。其中主要方法有：贵金属修饰、半导体复合、染料敏化和金属离子掺杂等。2001年Asahi等发现氮掺杂能减小TiO2禁带宽度，提高其在可见光区的光学活性。在此之后又相继出现碳、硼、硫、氟等非金属元素掺杂可以使TiO2在可见光区出现一定光催化性能的报道。

Using TiCl4 as the titanium source, nanoparticles of TiO2 doped with nitrogen（N-TiO2） were synthesized by triethylamine. TiO2 powder codoped with iron and nitrogen（Fe/N-TiO2） were prepared by adsorption-deposition of Fe^3＋ on N-TiO2 and calcining at 400 ℃ for 2 h. From the XPS results for Nls binding energy at 399.6 eV and 396.6 eV, it is proposed that the partial N atoms as substitution atoms replace for O atoms in TiO2 lattice. The onset of the absorption spectrum of Fe/N-TiO2 has a 45 nm red-shift compared with that of TiO2. The results of photocatalytic degradation of methylene blue solution indicate that Fe/N-TiO2 （0.45% Fe^3＋） has a higher activity. Its photocatalytic activity is about 2 times as high as that of pure TiO2 under UV-light, and 3 times under sunlight. Doping of nitrogen in TiO2 enhances photoresponse in visible light region and doping of Fe^3＋ reduces the recombination of electrons and holes. Both of the above effects are beneficial for improving the performances of Fe/N-TiO2 photocatalyst.