Abstract:SiO<inf>2</inf>/TiO<inf>2</inf> sols were prepared via a novel sol-gel process using TiCl<inf>4</inf> and industrial SiO<inf>2</inf> sol as starting material precursors. A series of SiO<inf>2</inf>/TiO<inf>2</inf> composite films were formed via a dip-coating route on ceramic substrates precoated with 4 layers of Al<inf>2</inf>O<inf>3</inf> films, and characterized using an X-ray diffractometer (XRD), a field-emission scanning electron microscope (FE-SEM) and a Fourier transform infrared (FT-IR) spectrometer. The effect of SiO<inf>2</inf> on the anatase-rutile phase transformation in the films was also examined. The results showed that the presence of SiO<inf>2</inf> greatly retarded the anatase-rutile transformation and inhibited the grain growth of TiO<inf>2</inf>. The anatase-rutile transformation temperature increased from 700°C (in the case of pure TiO<inf>2</inf>) to 1000°C (in the case of using 10 mol% SiO<inf>2</inf>). The average crystalline size of TiO<inf>2</inf> in the films after calcination at 1000°C was about 28 nm. The photocatalytic activities of the films were evaluated based on degradation rates of a methylene blue solution under UV irradiation, and the results revealed that double layered SiO<inf>2</inf>/TiO<inf>2</inf> composite films calcined at 700°C exhibited the highest photocatalytic BV activity. Copyright © 2015 American Scientific Publishers All rights reserved.
Volume:7
Issue:4
Translation or Not:no