Simple sol-gel process to obtain silica-coated anatase particles with enhanced TiO2-SiO2 interfacial area.

In this study we prepared silica-titania composites with a low SiO2:TiO2 molar ratio. These materials were prepared using a simple sol-gel route in which a hydrothermal treatment was used to obtain mesoporous anatase particles. Pure titania was also synthetized for comparison purposes. These materials were examined by scanning and transmission electron microscopy (SEM and TEM, respectively), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and nitrogen sorption tests. A thin silica coating was formed on the anatase particles. It was observed that the presence of this coating led to samples with an enhanced thermal stability. Indeed, the composites prepared in this work showed an anatase structure and a high specific surface area (SSA), even after their calcination at 800°C. Thus, we believe that the synthetized material present an outstanding SiO2-TiO2 interfacial area associated with a high amount of anatase particles which could improve its photoactive properties.