Highly crystalline and silica-embedded titania rhombic shaped nanoparticles with mesoporous structure and its application in photocatalytic degradation of organic compound

Highly crystalline and silica-embedded titania rhombic shaped nanoparticles with mesoporous structure are successfully obtained via a facile solvothermal method using Ti(OC4H9)4 as precursor, acetic acid as solvent and Si(OC2H5)4 (TEOS) as stabilizer. Various characterization techniques, including Transmission electron microscopy(TEM), X-ray diffraction(XRD), UV–vis diffuse reflection spectroscopy, Raman spectroscopy, N2 adsorption–desorption isotherms and X-ray photoelectron spectra (XPS), have been applied to investigate the physical–chemical properties and the formation process of silica-embedded titania. The photocatalytic performances of all the silica-embedded titania samples are also studied by the degradation of methylene blue (MB) dye under UV irradiation. The results indicate that the mesoporous silica-embedded titania nanocrystals exhibit rhombic or truncated rhombic shapes and have extremely high special surface area of 260.7 m2 g−1. All the highly crystalline and mesoporous silica-embedded titania samples show better photocatalytic activity than that of the pure titania. The maximum photocatalytic activity is obtained on the silica-embedded titania nanoparticles with 0.6 ml TEOS, which is 6.7 times that achieved on the pure titania sample and 1.5 times that performed on the Degussa P25 powders. This is attributed to high crystallinity, increased surface area by embedding amorphous silica and proper assembly of TiO2 nanoparticles.