Novel magnetically separable Fe3O4@ZnO/AgCl nanocomposites with highly enhanced photocatalytic activities under visible-light irradiation

Abstract

A simple and large-scale method was applied for preparation of novel magnetically separable Fe3O4@ZnO/AgCl nanocomposites at a low temperature of 96°C in water. The prepared photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDX), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), Fourier transform-infrared spectroscopy (FT-IR), and vibrating sample magnetometery (VSM) techniques. Photocatalytic activities of the nanocomposites were investigated by degradation of rhodamine B (RhB) under visible-light irradiation. The activities of the nanocomposites were enhanced by increasing the weight ratio of ZnO/AgCl to Fe3O4 up to 10 and then decreases. The degradation rate constant of RhB on the Fe3O4@ZnO/AgCl (1:10) nanocomposite is about 35-fold higher than that of the Fe3O4@ZnO nanocomposite. The activity of the nanocomposite increases with refluxing time up to 90min and then decreases. Furthermore, the degradation reaction over the nanocomposite without any thermal treatment was faster than those of the calcined samples. The trapping experiments showed that superoxide ions and holes have major influences on the degradation reaction. More importantly, the nanocomposite was successfully separated from the treated solution in four cycles by applying an external magnetic field.