铁铈共掺杂TiO_2纳米复合体的制备及光催化性能

PREPARATION AND PHOTOCATALYTIC PERFORMANCE OF Fe/Ce CO-DOPED TiO_2 NANOCOMPOSITES

采用微乳法制备了纯TiO2纳米粉体、Fe掺杂TiO2(Fe-TiO2)、Ce掺杂TiO2(Ce-TiO2)和Ce、Fe共掺杂TiO2(Fe/Ce-TiO2)纳米复合体。通过X射线衍射、扫描电镜和紫外漫反射光谱等对样品的结构和形态进行表征。以甲基橙溶液为标准模拟降解物,对Fe/Ce-TiO2、Fe-TiO2、Ce-TiO2和纯TiO2光催化降解性能进行评价。结果表明:Fe、Ce掺杂后TiO2的光催化性能明显提高,原因是Fe、Ce掺杂不仅能抑制TiO2晶粒生长,提高TiO2的热稳定性和比表面积,而且能够拓展TiO2的吸收波长范围至可见光区,降低了光生载流子的复合几率。共掺杂对TiO2光催性能的提高具有双重效应,使Fe/Ce-TiO2光催化活性明显高于Fe-TiO2的和Ce-TiO2的。500℃制备的Fe/Ce-TiO2对甲基橙降解效果最佳,归功于热处理温度对晶型和晶粒尺寸的影响。

Pure TiO2,Fe-doped TiO2,Ce-doped TiO2,and Fe/Ce co-doped TiO2 nanocomposites were prepared by the micromulsion method. The obtained samples were characterized by the thermogravimetric–differential thermal analysis,X-ray diffraction,scanning electronic microscope,and diffuse reflection spectroscopy. Their photoactivity was evaluated by degradation of methyl orange under ultraviolet irradiation. The results show that the photoactivity of TiO2 is greatly increased by Fe or Ce doping. This is attributed to the fact that the addition of Fe and Ce not only sustains crystalline growth and improves the thermostability and surface areas of TiO2, but also shifts the excitation wavelength of TiO2 to visible light regions and decreases the recombination ratio of the photo-generated current cartier. Additionally, due to the dual effects of co-doping on the photoactivity increase of TiO2, the photoactivity of Fe/Ce-TiO2 is evidently higher than that of Fe-TiO2 and Ce-TiO2. Meanwhile, Fe/Ce-TiO2 annealed at 500 ℃ has the highest photoaetivity due to the effect of the heat treatment temperature on the phase and crystalline size.