Functionalization of tungsten oxide into MWCNT and its application for sunlight-induced degradation of rhodamine B

A composite of multi-walled carbon nanotube/tungsten oxide (MWCNT/WO3) has been successfully synthesized. The prepared composite was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The catalytic activity was investigated by rhodamine B degradation under solar irradiation. The influence of various degradation parameters such as solar illumination time, initial dye concentration, dosage and pH was investigated. It was found that the composite exhibits an enhanced photocatalytic activity as compared with WO3 and a mechanical mixture of MWCNTs and WO3. The enhancement in photocatalytic performance of the MWCNT/WO3 composite has been explained based on adsorption ability and electron transportation as a result of a strong interaction between WO3 and MWCNTs. Besides, MWCNTs acts as dispersing agent preventing WO3 from agglomerating during the catalytic process, providing a high active surface area of the catalyst. A reasonable mechanism for the enhanced reactivity was proposed. (C) 2011 Elsevier Inc. All rights reserved.