锌离子掺杂的二氧化钛介孔空心微球的制备及光催化性能

以二氧化硅为模板,钛酸四丁酯(TBOT)为钛源,硝酸锌为锌源,采用溶胶凝胶法制备了锌离子掺杂的介孔二氧化钛空心微球。采用X射线衍射(XRD)、比表面积(BET)、透射电镜(TEM)、扫描电镜(SEM)和X射线光电子能谱(XPS)等技术对样品进行表征,以亚甲基蓝(MB)的光催化降解为目标反应评价其光催化活性。结果表明,去核之后的复合微球为空心微球,壁厚为20 nm左右。钛酸四丁酯溶液的滴加时间对微球的形貌影响较大,当滴加时间大于15 min时,可以得到结构清晰的空心微球。用氢氧化钠溶液去除二氧化硅核,反应90 min,二氧化硅可以被完全去除。X射线衍射表明,实验得到的掺杂锌离子的空心微球和没有掺杂锌离子的空心微球都是锐钛矿。当锌离子的摩尔分数为0.3%时,二氧化钛空心微球的晶粒尺寸最小,比表面积最大,催化亚甲基蓝降解的效率最高。

Zinc Doped TiO2 Mesoporous Hollow Microspheres: Preparation and Photocatalytic Activity

Zinc doped TiO₂ mesoporous hollow microspheres were synthesized based on sol-gel method by using SiO₂ as the template, tetra-n-butyl titanate as Ti source and Zinc nitrate hexhydrate as Zinc source. The prepared samples were characterized by means of X-ray diffraction (XRD), low temperature nitrogen adsorption-desorption (BET surface area), transmission electron microscope (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Methyl blue dye was used as a target dye to evaluate the photocatalytic activity of the samples. The results show that microspheres are hollow after removing the SiO₂ template using an aqueous solution of NaOH and it takes more than 90 min to completely remove the SiO₂ template. The thickness of the TiO₂ shell is about 20 nm. The dropping rate of tetra-n-butyl titanate solution plays an important role in the structure. When the dropping time exceeds 15 min, the obtained hollow microspheres have clear structure. The XRD results indicate that pure hollow microspheres and Zinc doped hollow microspheres exist in the form of anatase. When the doping molar ratio of Zn²⁺ to tetra-n-butyl titanate is 0.3%, the obtained hollow microspheres have the smallest particle size, the biggest BET surface area and show the most efficient degradation of methyl blue dye.