铁氮共掺杂纳米TiO2复合膜的制备、光谱分析及光催化活性研究

Preparation,Spectral Analysis and Photocatalytic Activities of TiO_2 Films Codoped with Iron and Nitrogen

用溶胶-凝胶法制备铁、氮共掺杂纳米TiO2凝胶,浸渍-提拉法将其镀膜于载玻片表面,经干燥、煅烧,制得Fe-TiO2-xNx复合膜;用XRD,SEM,XPS及UV-Vis对镀膜样品进行了表征。XRD分析表明,Fe-TiO2-xNx膜为锐钛矿结构,少数氮原子替代了TiO2晶格中的氧;SEM照片说明,构成膜的粒子分散均匀,形貌一致,粒径约19nm;UV-Vis漫反射光谱显示,Fe3+掺杂可使复合膜对可见光的响应红移至740nm处;XPS图谱证明,铁、氮的掺入降低了Ti(2p3/2)电子结合能,从而拓宽了TiO2在可见光区的吸收范围。以光催化降解苏丹红Ⅰ为模型反应,比较了不同掺杂样品的光催化活性,结果表明,当掺杂的Fe3+相对于Ti4+的原子比达到0.4%时,复合膜表现出最佳催化性能,4h后对苏丹红Ⅰ的降解率达到97%。方法制备的氮和适量铁共掺杂Fe-TiO2-xNx复合膜能协同提高TiO2对可见光的响应能力及光催化活性,在污水处理领域具有潜在的应用价值。

Using tetrabutyl titanate as the titanium source, and ammonia and ferric nitrate as the sources of nitrogen and ferrum respectively, iron and nitrogen-codoped nano-TiO2 gelatins were prepared by sol-gel method. The iron and nitrogen-codoped nano-TiO2 complex films were prepared with the obtained gelatins used to coat the surface of cleaned glass slides by several times of dipping-lifting procedure, followed by natural seasoning at room temperature and calcined at 450 ℃ for 3 hours, then the films were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, X-ray photoelectron spectrum （XPS） and ultraviolet-visible diffuse reflectance spectrum （UV-Vis）. The XRD spectra of samples showed that the Fe-TiO2-x Nx films were of anatase structure with a few of oxygen atoms in the lattice of anatase TiO2 substituted by nitrogen atoms, resulting in the distorsion of crystal lattice. The SEM image showed that the nanoparticles of the films have a good dispersion characteristic and uniform orbicular shape with an average diameter of about 19 nrn. The absorption edges of UV-Vis spectra exhibited a red shift up to 740 nm when the TiO2 films were codoped with iron and nitrogen. The XPS of the Fe-TiO2-xNx film presented a lowering of Ti 2p3/2 electron binding energy because of the codoping of iron and nitrogen, which then resulted in the widening of the absorption of visible light range. The photocatalytic properties were studied by photocatalytieal degradation of sudan I as a model reaction in a self-assembled light-reactor. When the atomic ratio of Fe^3＋/Ti^4＋ reached 0. 4%, the Fe-TiO2-xNx film showed the highest catalytic performance in degradation of sudan I which was decomposed by up to 97% after 4 hours of photocatalytic reaction. Codoping of nitrogen and appropriate amount of iron in TiO2 enhances photoresponse and utilizing efficiency in visible light region, and then improves the performances of Fe-TiO2-x Nx photocatalyst. The complex film catalyst prepared by this method will have potential application in areas of wastewater disposal.