Effective fenton catalyst from controllable framework doping of Fe in porous silica spheres

Abstract Controllable doping of iron (Fe) (3.9–17.8%) in hollow porous silica spheres with highly homogeneous distribution state was achieved successfully by a one-pot hydrothermal synthesis strategy. Based on the observation and analysis by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, nitrogen sorption, and X-ray photoelectron spectroscopy (XPS), it was found that molecular Fe species were intercalated into silica framework during the structural transformation of silica to hollow flake-shelled spheres, which leads to both stable fixation with open accessibility of Fe and high surface area of the Fe-doped silica hollow spheres (Fe-SHSs). When used as heterogeneous Fenton catalyst to degrade the dye of Acid orange 7 (AO7), enhanced catalysis performance was exhibited due to the sufficiently exposed active sites and fast mass transport in the system. The optimal catalysis condition was also studied by adjusting Fe-SHSs dosages, oxidant concentrations, and pH values). This work presents an effective strategy for chemical doping of metal components in the silica structures and may also be explored for other supported metal catalyst systems.