Guo Yu, Jin Yu-jia, Wu Hong-mei, Li Dong-xin
Guang Pu Xue Yu Guang Pu Fen Xi. 2015 Jun;35(6):1677-81.
Titanium dioxide (TiO2) supported on spherical alumina substrate was prepared by using sol-gel method combined with dip-coating process. The surface morphology and structure of the synthesized samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) pattern. The results show that the morphology of the supported TiO2 composite material was obviously different from that of the original support. It reveals a layer formed by anatase TiO2 nanoparticles of 10-20 nm was deposited on the alumina substrate. Energy dispersive X-ray spectroscopy (EDX) analyses on the spherical alumina substrate and the resulting TiO2 composite catalyst were performed to determine the TiO2 loading content in the samples. It indicates that the TiO2 loading content on alumina substrate could be effectively increased by increasing the times of dip-coating alumina support in TiO2 sol. When dip-coating times increased to 5, the TiO2 loading content increased from 3.8 Wt. % to 15.7 Wt. %. In addition, the photocatalytic performances of the supported TiO2 materials prepared by different dip-coating times have been investigated by degrading methylene blue. It was found that the surface morphology of the supported TiO2 material was not only improved, but also the photocatalytic activity could be promoted significantly by increasing the dip-coating times. When the alumina substrate was dip-coated in TiO2 sol from 1 to 4 times, the degradation rate of methylene blue increased from 40% to 83.1%. However, after dip-coating the alumina support in TiO2 sol for 5 times, the degradation of methylene blue was only up to 85.6%. This indicates that the photocatalytic activity increased slowly when the TiO2 content in the supported catalyst was up to some extent. It is attributed to the continuous dip-coating resulted in less opportunities and weak intensity of illumination for the TiO2 nano-particles that under lower layer. The photocatalytic activity was relatively stable after repeated use of the supported TiO2 material for 5 times.
采用溶胶 - 凝胶法结合浸涂工艺制备了负载在球形氧化铝载体上的二氧化钛（TiO₂）。通过扫描电子显微镜（SEM）和X射线衍射（XRD）图谱对合成样品的表面形貌和结构进行了表征。结果表明，负载型TiO₂复合材料的形貌与原始载体明显不同。结果显示在氧化铝载体上沉积了一层由10 - 20 nm的锐钛矿型TiO₂纳米颗粒形成的层。对球形氧化铝载体和所得的TiO₂复合催化剂进行了能量色散X射线光谱（EDX）分析，以确定样品中TiO₂的负载量。结果表明，通过增加氧化铝载体在TiO₂溶胶中的浸涂次数，可以有效提高氧化铝载体上TiO₂的负载量。当浸涂次数增加到5次时，TiO₂负载量从3.8重量%增加到15.7重量%。此外，通过降解亚甲基蓝研究了不同浸涂次数制备的负载型TiO₂材料的光催化性能。结果发现，增加浸涂次数不仅可以改善负载型TiO₂材料的表面形貌，还可以显著提高其光催化活性。当氧化铝载体在TiO₂溶胶中浸涂1至4次时，亚甲基蓝的降解率从40%提高到83.1%。然而，将氧化铝载体在TiO₂溶胶中浸涂5次后，亚甲基蓝的降解率仅达到85.6%。这表明当负载型催化剂中TiO₂含量达到一定程度时，光催化活性增加缓慢。这是由于连续浸涂导致下层TiO₂纳米颗粒的光照机会减少且光照强度减弱。负载型TiO₂材料重复使用5次后光催化活性相对稳定。
