Abstract
Many products with relation to environmental improvement have been developed by using the photocatalytic activity of the titanium dioxide. In a heterogeneous photocatalytic system, the solid catalyst can either be suspended in liquid or be supported on substrate materials. Therefore, it had been considered that the utilization of magnetic separation could help recover fine photocatalytic particles with higher photocatalytic activity. In this work, the monodisperse pseudocubic photocatalytic particles with magnetism were prepared by gel-sol and sol-gel methods in liquid phase. These particles prepared have the core-shell structure of three layers. Core iron oxide particle sizes were controlled by reaction temperature from 0.6 to 2.2µm. The thicknesses of silica and titania layer were controlled at several nanometer by the concentration of metal alkoxides and seed particles. The photocatalytic activities were investigated by the decomposition experiments of a methylene blue under the ultraviolet irradiation. It was found that from the decomposition experiments of a methylene blue, the prepared photocatalytic particles had good photocatalytic activities and that they can be easily separated by magnetism. Furthermore, the result of the decomposition experiments revealed that the thicknesses of titanium layer mainly influenced on the photocatalytic activity
