Preparation, Characterization and Photocatalytic Activity of Pt-SiO2/TiO2 with Core-Shell Structure

SiO2/TiO2 photocatalyst with core-shell structure were synthesized by sol-gel method, using SiO2 microsphere with a mean size of about 300 nm as template. And then Pt was deposited on SiO2/TiO2 by chemical reduction method. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra (PL). The results show that Pt particles mainly in form of Pt(0) can be deposited on SiO2/TiO2 surface un-uniformly. The absorption in visible light region and the separation efficiency of electron-hole pairs are enhanced obviously via Pt-deposition. The adsorption and kinetic constants of Rhodamine B (RB) over the obtained samples were evaluated. The results indicate that core-shell structure is helpful to improve the adsorption property. The presence of Pt on SiO2/TiO2 surface is found to significantly enhance the photodegradation of RB, and the optimal deposition of Pt is 0.5 wt%.