Zn^(2+)/TiO_2中空纤维纳米材料模板辅助的两步法制备及其光催化性能

Preparation of Zn^(2+)/TiO_2 hollow fiber nanomaterials via a novel template-assisted two-step method and their photocatalytic performancel

利用一种模板辅助的两步法制备了一系列Zn2+掺杂的TiO2中空纤维纳米材料(Zn2+/TiO2);利用扫描电子显微镜(SEM)、X射线衍射(XRD)、X光电子能谱(XPS)和紫外-可见光谱(UV-Vis)等技术进行表征;以亚甲基蓝(MB)的降解为模型反应,考察Zn2+量对TiO2中空纤维纳米材料光催化性能的影响。结果表明:制备的样品为复制了模板形貌的中空结构纳米纤维材料;在0.00～0.62%Zn2+量范围内,Zn2+/TiO2的光催化活性明显高于TiO2的,且随掺杂量呈先增后降的变化趋势,当Zn2+量在0.29%左右时,其光催化活性最高,在太阳光下3h,MB溶液在Zn2+/TiO2表面的脱色降解率达98%以上,而在TiO2表面仅为60%;Zn2+/TiO2在重复使用5次时仍能保持MB溶液脱色率在90%以上。样品Zn2+/TiO2所表现出的优良催化性能是众多因素-表面羟基、吸附氧、Zn2+活性位、特殊的纤维形貌等协同作用的结果。

A series of Zn2＋-doped TiO2 hollow fiber nanomaterials were prepared via a novel template-assisted two- step method and characterized by the X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, scanning electron microscope（SEM） and UV-vis spectrometer（UV-Vis）. The degradation of methyl blue（MB） was used as the model reac- tion to investigate the effect of Zn2＋ on the photocatalytic property of TiO2. The results showed that the samples copied morphology of the cotton template and were hollow. In the range of 0. 00 to 0. 62 at. % Zn2＋ , the photocatalytic activity of Zn2＋/TiO2 was higher than that of TiO2 and firstly was increased with increasing Zn2＋ amount and reached optimal at a- bout 0.29 at. %,and then decreased with further increasing Zn2＋. On the surface of 0. 29 at.% Zn2＋/TiO2, the degradation efficiency of MB was above 98% when the reaction time was 3h under the sunlight and the efficiency was kept above 90% when it was repeatedly used for 5 times while on the TiO2 the efficiency was only 60%. The enhanced photocatalytic activi- ty of Zn2＋/TiO2was ascribed to a synergistic effect of many factors, such as surface hydroxyl groups, adsorbed oxygen, Zn2＋ sites,and special fiber morphology.