复合方式对MWCNTs/TiO2纳米复合薄膜光电化学性能的影响

采用溶胶-凝胶法制备了不同复合方式的系列多壁碳纳米管(multi-walled carbon nanotubes, MWCNTs)/TiO2纳米复合薄膜电极. 通过SEM表征了薄膜的表面形貌, 并测定了MWCNTs引入前后对TiO2晶型结构和光吸收性能的影响以及不同复合方式的纳米复合薄膜的光电化学特性. 结果表明, MWCNTs/TiO2纳米复合薄膜表面形成无序多孔的形貌, 其光谱吸收边可拓展到可见光区; MWCNTs底层分布的纳米复合薄膜比纯TiO2表现出更好的光电活性, 而MWCNTs在表层分布及均匀分布的纳米复合薄膜的光电活性相对较差. 依据载流子分离原理探讨了不同复合方式对纳米复合薄膜光电性能的影响, 底层分布MWCNTs的纳米复合薄膜由于MWCNTs有效地收集传递电子并阻止载流子的复合从而提高了光电化学活性.

Effect of Composite Modes on Photoelectrochemical Properties of MWCNTs/TiO2 Nanocomposite Films

A series of nanocomposite of TiO2 thin films and multi-walled carbon nanotubes (MWCNTs) in different forms were prepared by sol-gel methods. The surface morphologies of the nanocomposite films were characterized via scanning electron microscopy (SEM). The effects of inducing MWCNTs into TiO2 thin film on the structure and absorption properties of TiO2 were characterized by X-ray diffraction (XRD) and UV-Vis spectrophotometer methods. The nanocomposite films were also characterized by photoelectrochemical methods. The results showed that the MWCNTs/TiO2 nanocomposite films were porous and rough and the absorption edge can extend to visible light region. The photoelectrochemical properties of TiO2 could be evidently enhanced by bottom distribution mode, or otherwise, decreased by surface distribution mode and uniform distribution mode. The effects of composite modes on the photoelectrochemical activities were discussed in terms of separation of charge carriers. MWCNTs distributed in bottommode within the nanocomposite filmcould improve electron-collecting efficiency and reduce recombination.