Ag-TiO_2/CNTs的复合及光催化性能

Preparation and photocatalytic properties of composites of carbon nanotubes loaded with Ag and TiO_2 nanoparticle

以钛酸四丁酯、硝酸银、碳纳米管为原料,通过溶胶-凝胶法制备了系列不同碳纳米管含量和热处理温度下的掺银TiO2颗粒/碳纳米管(Ag-TiO2/CNT)的复合催化剂,以甲基橙为目标降解物考察复合物的光催化活性。利用X-射线衍射(XRD),透射电子显微镜(TEM)和电子探针能谱仪(EDS)对所制的Ag-TiO2/CNTs复合材料进行了表征。结果表明:掺银TiO2颗粒在碳纳米管上均匀分布,所制复合材料具有较高的光催化性能。不同的热处理温度决定着催化效率的高低,在实验条件下,当热处理温度为600℃时,复合物的光催化活性较高。随碳纳米管含量的增加,催化活性逐渐增大,当碳纳米管的负载量在3.5%(碳纳米管/TiO2,重量百分比)时,催化活性达到最大值,超过该比例时,催化活性反而呈下降趋势。在600℃、碳纳米管负载量3.5%时,复合物光催化活性最高,降解率达90%以上。

A series of different carbon nanotube content and heat treatment temperature of composites of carbon nanotubes loaded with Ag and TiO2 nanoparticles（Ag-TiO2/CNTs） have been prepared by sol-gel method using tetrabutyl tianate, silver nityate and carbon nanotubes as raw materials. The photocatalytic activity of prepared composites was evalua- ted by the degradation of methyl orange. The Ag-TiO2/CNTs composites were characterized using X-ray diffraction（XRD）, transmission electron microscopy（TEM）and electron probe energy dispersive spectroscopy（EDS）. The results showed that the carbon nanotubes in the composites were uniformly covered well（ by Ag-TiO2 nanoparticles. And the composites exhibi- ted a high photocatalytic activity. It was founded that the level of catalytic efficiency was depended to the different heat treatment temperature. Under the experimental condition, the best heat treatment temperature was 600℃. With increasing the content of carbon nanotubes, the catalytic activity gradually increased. The optimum weight ratio of carbon nanotubes o- ver titanium dioxide in the composites was founded to be 3. 5 %, at the same time the photocatalytic activity can reach its maximum. However, when more than the proportion, the catalytic activity declined instead. All in all, using the composite photocatalyst prepared with 600℃ calcinations for 2h and 3. 5% carbon nanotubes, the photocatalytic activity can achieve highest and the degradation rate can up to more than 90%.