Synthesis of CeO2-SiO2 Composite Nanoparticles by Coprecipitation Method and Dispersion Stability of their Suspension

A series of CeO2-SiO2 composite nanoparticles with different cerium and silica (Ce/Si) mole ratios were synthesized via a coprecipitation method using cerium nitrate, tetraethylorthosilicate and ammonia as raw materials. X-ray diffraction (XRD), fourier transform infrared spectrology (FT-IR), thermogravimetry-differential scanning calorimetry (TG/DSC), transmission electron microscopy (TEM) and energy dispersive analysis of X-ray (EDAX) were used to characterize the CeO2-SiO2 nanoparticles. With the increase of CeO2 content, the crystal of CeO2 grew up gradually and the average crystallite size of the CeO2 decreased. There are Ce-O-Si bonds in the CeO2-SiO2 composite nanoparticles. The particle size of the CeO2-SiO2 composite nanoparticles with a Ce/Si mole ratio of 1 is about 20–30 nm. The dispersion stability of the CeO2-SiO2 composite nanoparticles with a Ce/Si mole ratio of 1 was studied. It was found that cationic and nonionic surfactant could obviously affect the dispersion stability of suspension, but not the anion surfactant. A suspension with CeO2-SiO2 composite nanoparticles at 0.1 wt% was added in 0.1 g/L cationic surfactant CTAB, and its pH value was adjusted within the range of 10-10.5. In this condition, the stable suspension without sedimentation time was successfully obtained.