Study on enhanced photocatalytic activity of magnetically recoverable Fe3O4@C@TiO2 nanocomposites with core–shell nanostructure

Abstract

A novel and simple approach for the fabrication of Fe3O4@C@TiO2 nanocomposites with a good core–shell structure has been successfully constructed. The as-synthesized core–shell structure is composed of a magnetic core, an interlayer of carbon, and an outer TiO2 shell. In this method, the carbon middle layer could provide negatively charged for the TiO2 coating without the surfactants. The as-obtained core–shell structure composites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray photoelectron spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG), N2 adsorption–desorption isotherm analyses and the magnetization measurement (SQUID). The TEM images showed that the thickness of TiO2 shell could be controlled by varying tertrabutyl titanate (TBOT) content in the ethanol/acetonitrile mixed solvents. Photocatalytic property of Fe3O4@C@TiO2 nanocomposites were evaluated by photodegradation methylene blue (MB). The results showed that the well-designed nanocomposites exhibited a higher photoactivity than Fe3O4@TiO2 nanocomposites. Moreover, this photocatalyst can be easily recovered by an external magnetic field and remain stable photocatalytic activity after five cycles. The presence of carbon interlayer can avoid the occurrence of photodissolution. Therefore, the photocatalytic activity of titania would not deteriorate seriously, which played key role for the enhanced photocatalytic activity.