Preparation and Characterization of SiO2/TiO2-Pt Core/Shell Nanostructures and Evaluation of Their Photocatalytic Activity

SiO2/TiO2-Pt core/shell nanostructures with Pt nanoparticles well dispersed in the TiO2 shell were prepared and characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. The photocatalytic activity of the samples was evaluated using the reaction of decomposition of orange II in liquid phase. While the SiO2/TiO2-Pt nanostructure displayed a similar photocatalytic activity to that of Degussa P25, the former can be easily separated from the reaction medium by sedimentation. Interestingly, the photocatalytic activity of the core/shell nanostructures was observed to be improved upon catalyst recycling. It was also observed that the presence of Pt can indeed enhance the photocatalytic performance of TiO2 catalyst. The photocatalyst described in this work represents a potential catalyst system for practical applications in water treatment.