Preparation of monodispersed silica particles coated with ceria and control of coating thickness using sol-type precursor

Monodispersed silica particles coated with ceria were prepared using a peptized ceria sol as coating precursor. The ceria coating precursor was synthesized by alkoxide method, which employs ethanol as solvent. The resulting particles were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and zeta potential measurements. It was found that crystalline ceria coating was formed on the surface of silica particles at temperature of 60 °C without requirement for the post-heat treatment. The thickness of ceria coating was controlled by changing the concentration of the coating precursor. The influence of solution pH on the formation of ceria coating was investigated in terms of electrostatic attraction mechanism. The apparent surface coverage was estimated using an isoelectric point (IEP) data.