TiO2@SiO2 Composites: Preparation and Photocatalytic Antimicrobial Performance

Abstract

Carrier SiO2 was synthesized through Sol-Gel method, and the photocatalytic antibacterial material of TiO2@SiO2 composite was prepared by hydrolysis method. The synthesized composites were characterized. The photocatalytic properties of the composites were investigated by degrading methyl orange with UVA irradiation. After 3 h irradiation, all of composites with different amount of titanium doping can reach 99.9%. And the optimal catalytic efficiency of the composite is obtained when the titanium doping ratio (molar ratio) is 0.58. Antibacterial effect of composites on Escherichia coli, measured by plate coating method, shows that the antibacterial properties are improved with the increase of titanium content, which reach up to 92% under UVA irradiation. Moreover, the composites also exhibit favourable antibacterial properties under visible irradiation. Though fluorescence detection of bacterium, it is proved that the reactive oxygen species (ROS) produced by the composites migrate into the cells and cause the oxidative damage of the cells, which is a significant basis for the antibacterial mechanism of photocatalytic materials.