Photocatalytic Degradation of Methyl Orange by a New Photoctalyst Multi-Walled Carbon Nanotues (MWCNTs)/TiO2/CdS Nanocomposite

Composite photocatalysts using TiO2 coated by Multi-walled carbon nanotues(MWCNTs) and CdS were prepared by sol-gel process. The purpose of adding MWCNTs and CdS was extending the light absorbance range of pure TiO2 to visible light. Methyl orange (MO) was chosen as an object. The degradation of MO by MWCNTs/TiO2/CdS composite photocatalysts under visible light irradiation was studied. The results showed that the presence of MWCNTs and CdS can enhance the photoefficiency of TiO2 greatly. In addition, The photocatalyst was used for five cycles with photocatalytic degradation efficiency still higher than 96%. The photocatalytic degradation of MO followed a first-order kinetics according to the Langmuir-Hinshelwood model. A possible decomposing mechanism for the photocatalytic oxidative degradation was also discussed. The results of the study showed the potential use of MWCNTs/TiO2/CdS composite in degradation of toxic organic pollutants.