Sonochemical Synthesis of Networked Silica Shell with Reduced Microporosity on Titania Nanocores for Photocatalytic Activity Reduction

Silica shells with a high density of networks and reduced microporosity has been formed on titania nanocores via a sonochemical approach in the absence of ammonia as a hydrolyzing catalyst. The TiO2-silica core-shell nanoparticles were characterized by transmission electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy (FTIR), and microporosity measurements. The photocatalytic activity of coated titania was also reported. FTIR measurements showed that the silica shell was formed with a high density of networks through the formation of asymmetric Si-O-Si vibration and asymmetric Si-O-Si stretching vibration bonds. Moreover, the thickness and microporosity of the silica shell could be altered by controlling the sonochemical power and time parameters.