Enhanced photocatalytic degradation of Safranin-O by heterogeneous nanoparticles for environmental applications

Nanostructure titanium dioxide (TiO2) has been synthesized by hydrolysis of titanium tetrachloride in aqueous solution and Ag-TiO2 nanoparticles were synthesized by photoreduction method. The resulting materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier-transform infrared (FT-IR) and UV-vis absorption spectroscopy. The experimental results showed that the sizes of the synthesized TiO2 and Ag-TiO2 particles are in the range of 1.9-3.2 nm and 2-10 nm, respectively. Moreover, Ag-TiO2 nanoparticles exhibit enhanced photocatalytic activity on photodegradation of Safranin-O (SO) dye as compared to pure TiO2. The positive effect of silver on the photocatalytic activity of TiO2 may be explained by its ability to trap electrons. This process reduces the recombination of light generated electron-hole pairs at TiO2 surface and therefore enhances the photocatalytic activity of the synthesized TiO2 nanoparticles. The effects of initial dye and nanoparticle concentrations on the photocatalytic activity have been studied and the results demonstrate that the dye photodegradation follows pseudo-first-order kinetics. The observed maximum degradation efficiency of SO is about 60% for TiO2 and 96% for Ag-TiO2. (C) 2010 Elsevier B.V. All rights reserved.