Enhanced Photocatalytic Degradation of CI Basic Violet 2 Using TiO2-SiO2 Composite Nanoparticles

In this report, TiO2-SiO2 composite nanoparticles were prepared by the thermal hydrolysis method using titanium tetrachloride and tetraethylorthosilicate as TiO2 and SiO2 precursors, respectively. The prepared nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), nitrogen adsorption/desorption and UV-Vis diffuse reflectance spectroscopy (DRS). The results indicated that, in comparison with pure TiO2, TiO2-SiO2 composite nanoparticles had a higher thermal stability, which prevents phase transformation from anatase to rutile. In addition, the TiO2-SiO2 nanoparticles had a higher specific surface area, larger pore volume, greater band gap energy and smaller crystallite size. Thus, the surface area of TiO2-40% SiO2 composite nanoparticles was about 17 times higher than that of pure TiO2 nanoparticles. The photocatalytic activity of TiO2-SiO2 composite nanoparticles in the photodegradation of C. I. Basic Violet 2 was investigated. The photodegradation rate of Basic Violet 2 using TiO2-40% SiO2 nanoparticles calcined at 600 degrees C was much faster than that using pure TiO2 and Degussa P25 TiO2 by 10.9 and 4.3 times, respectively. The higher photoactivity of the TiO2-SiO2 composite nanoparticles was attributed to their higher surface area, larger pore volume, greater band-gap energy and smaller crystallite size compared with pure TiO2.