Preparation and characterization of SiO₂@Fe₂O₃ core-shell catalysts

The monodisperse SiO₂ microspheres with average diameter of 230 nm made by optimized Stöber method were used as core to prepare core-shell structure SiO₂@Fe₂O₃ catalysts with different shell thickness through hydrolysis precipitation. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ physical adsorption and X-ray diffraction (XRD) were used to characterize the size, structure and morphology of catalysts and the effects of different preparation condition on morphology were discussed. The characterization results indicate that SiO₂@Fe₂O₃ catalysts possess obvious core-shell structure and the spherical morphology of catalyst is kept. Iron oxide nanoparticles are attached to the silica surface through hydroxyl-bond and a 2~10 nm thick dense shell is formed.