CdS/CNT-TiO2光催化剂的合成及其对亚甲基蓝的光催化降解

摘要

Novel CdS/CNT-TiO2 photocatalysts were synthesized by a simple chemical routine through the drop-wise addition of Na2S·5H2O solutions to cadmium acetate solutions containing purified multiwall carbon nanotubes (MWC-NTs).The CdS/CNT materials obtained were treated with titanium (Ⅳ) n-butoxide to form CdS/CNT-TiO2 composites which were characterized by N2 adsorption,XRD,TEM,SEM,and energy-dispersive X-ray analysis.The composites were found to be porous,and the MWCNTs were homogenously dispersed in the composites without any apparent agglomeration of TiO2 nanoparticles and CdS nanoparticles.The CdS/CNT-TiO2 composites exhibited excellent activity for the degradation of methylene blue under UV and visible-light irradiation.This was attributed not only to the photocatalysis of the supported TiO2 for the radical reaction and the adsorptivity of MWCNTs,but also to the introduction of the narrow-band gap semiconductor CdS that in.eases the transfer rate of photogenerated electrons through the surface of the%采用多壁碳纳米管( MWCNTs)为载体,分别以醋酸镉((CH3 COO)2 Cd·2H2 O)和硫化钠(Na2S·5H2O)为镉源和硫源,经简单逐滴滴入途径制备了CdS/CNT复合材料.再以四丁氧基钛(TNB)为钛源,苯为溶剂,成功地将二氧化钛(TiO2)纳米粒子沉积在CdS修饰的MWCNTs表面而得到CdS/CNT-TiO2光催化剂.利用N2吸附等温线、扫描电子显微镜、X射线衍射、能量分散性X射线分析以及透射电子显微镜对所制CdS/CNT-TiO2光催化剂进行表征.CdS/CT-TiO2复合材料呈多孔结构,MWCNTs均匀分散在材料中,且未出现明显的TiO2和CdS纳米颗粒团聚体.该材料在紫外和可见光照射下对亚甲基蓝具有优异的降解活性.这不仅归因于TiO2对自由基的反应和MWCNTs吸附能力,且归因于引入窄带隙半导体CdS,使粒子在MWCNTs表面的电子转移速率得到提高.