Magnetically recoverable core-shell nanocomposites γ-Fe2O3@SiO2@TiO2-Ag with enhanced photocatalytic activity and antibacterial activity

In this study, we synthesized gamma-Fe2O3@SiO2@TiO2-Ag nanocomposites with a core-shell structure using a hydrothermal method and a sol-gel method. Transmission electron microscope images showed that the gamma-Fe2O3@SiO2@TiO2-Ag nanocomposites had a core-shell structure. Photocatalytic examination of the gamma-Fe2O3@SiO2@TiO2-Ag was carried out using methyl orange solution under UV irradiation. The gamma-Fe2O3@SiO2@TiO2-Ag nanocomposites showed stronger photocatalytic activity than pure TiO2. With gamma-Fe2O3@SiO2@TiO2-Ag, about 84% of the methyl orange was decomposed after 1 h of UV irradiation, versus 49% for pure TiO2. The antibacterial activity of gamma-Fe2O3@SiO2@TiO2-Ag nanocomposites was remarkably greater than that of bare TiO2 nanoparticles. The introduction of silver nanoparticles into the TiO2 matrix facilitates charge separation by trapping photo-generated electrons, thereby enhancing biological activity and photoactivity. (C) 2012 Elsevier B.V. All rights reserved.