Fe/TiO_2光催化剂的结构和性能研究

Studies on the structures and performances of Fe/TiO_2 photocatalyst

采用溶胶-凝胶法制备了不同含量铁掺杂的纳米TiO2粉末,利用X射线衍射、X射线光电子能谱和紫外可见光谱技术对粉末的晶体结构和光吸收性能进行了表征。Fe/TiO2粉末中铁主要以Fe2O3存在,与TiO2形成了钛铁固溶体。TiO2的晶粒尺寸和相转变受焙烧温度的影响较大,焙烧温度越高,晶粒尺寸越大。铁掺杂后TiO2粉末的晶粒尺寸随焙烧温度升高的增大速度减慢。掺铁量越多,平均晶粒尺寸越小。铁掺杂后TiO2粉末的光谱吸收范围被明显拓展至可见光区,可以被较宽范围的可见光激发。光催化反应快慢与入射光波长有关,紫外光下Fe/TiO2粉末对甲基橙的光催化降解活性与纯TiO2粉末相比较差,而在可见光下,Fe/TiO2粉末对甲基橙的光催化降解活性明显好于纯TiO2粉末。

Iron-doped titania powders（Fe/TiO2） with different iron contents were prepared by using a sol-gel method. The crystalline structure and light absorption performance of Fe/TiO： powders were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis. absorption spectroscopy measurements. Iron exists mainly in Fe203, and it forms a titanium-iron solid solution with titania. The crystallite size of TiO2 and its phase structure are strongly affected by calcination temperature. The average crystallite size increases with the increase of calcination temperature. After doped with iron, the growth of the crystallite size of TiO2 with the increasing of calcination temperature has slowed down, and the photon excited wavelength of TiO2 powder was broaden to visible light region. The photocatalytic reactivity depends on the wavelength of the irradiating light. Under UV irradiation, the photocatalytic activity of TiO2 for the decomposition of methyl orange is higher than Fe/TiO2. Whereas, under visible light irradiation, the photocatalytic activity of the FefriO2 is higher than that of pure TiO2.