Photocatalytic and antibacterial properties of Au-decorated Fe3O4@mTiO2 core–shell microspheres

A facile approach for the fabrication of Au-decorated mesoporous Fe3O4@TiO2 (Fe3O4@mTiO2) core–shell microspheres is demonstrated. The protocol involved the coating of a successive layer of TiO2 onto a magnetic Fe3O4 core via a sol–gel process, followed by TiO2 crystallization and mesopore-formation by a hydrothermal treatment, and then the deposition of Au nanoparticles onto Fe3O4@mTiO2 microspheres through an in situ reduction of perchloric acid. The mesoporous microspheres (Fe3O4@mTiO2) showed stronger magnetic properties than the dense sample (Fe3O4@TiO2) before the hydrothermal treatment. The size and loading amount of Au nanoparticles were controlled by the reduction temperature and concentration of Au salt, respectively. Compared to unmodified Fe3O4@mTiO2 microspheres, Fe3O4@mTiO2@Au microspheres showed higher photocatalytic activity for organic degradation and antibacterial action in water. These core–shell Fe3O4@mTiO2@Au microspheres can serve as efficient and recyclable photocatalysts, which have promising applications in environmental treatment.