MWCNTs-TiO_2纳米复合材料的制备、表征及其光催化活性

Preparation and characterization of MWCNTs-TiO_2 nanocomposites and its photocatalytic activity

以水热法制备8种MWCNTs-TiO2纳米复合材料,通过XRD、SEM、Raman、BET、FTIR等方法对复合材料进行表征。以罗丹明B为降解目标物,考察MWCNTs-TiO2纳米复合材料在不同光源辐照下的光催化活性以及MWCNTs的管径和管长对复合材料光催化活性的影响。结果表明:MWCNTs与TiO2结合紧密,TiO2微粒均匀分散在MWCNTs上,引入MWCNTs能提高TiO2的比表面积,且不会改变TiO2的锐钛矿晶相。光催化过程中,MWCNTs的引入抑制复合材料中光生载流子复合,进而提高复合材料的光催化效率。紫外光辐照下,MWCNTs的引入对TiO2光催化活性有显著提高;而在可见光辐照下,管长较短的MWCNTs与TiO2复合后表现出更好的光催化活性,且MWCNTs(SM4)-TiO2表现出最佳的可见光催化活性,主要由复合材料在紫外光与可见光辐照下不同的光催化反应机制所致。

Multi-walled carbon nanotube（MWCNT）-TiO2 hybrid was prepared with hydrothermal method and characterized with X-ray diffraction,electron microscopy,N2-adsorption analysis,Raman spectroscopy and Fourier transform infrared spectroscopy.The photocatalytic activity of MWCNT-TiO2 hybrid under different light resources and the effects of the tube length were studied by photocatalytically degradating RhB.The results showed that the MWCNTs were evenly coated with TiO2 nanoparticles.There was an intimate contact between the MWCNTs and TiO2.The introduction of the MWCNTs provided MWCNTs-TiO2 hybrid with visible light-induced photoactivity and a large surface area.The lifetime of photogenerated electron/hole which can enhance the photocatalytic activity was prolonged.MWCNTs-TiO2 hybrid with long length MW had higher degradation efficiency under UV lights irradiation than that with short length MW.MWCNTs（SM4）-TiO2 with a short length CNTs had the best photocatalytic activity under visible lights irradiation due to the different mechanisms of photocatalysis.