Characterization of CeO₂ Fine Particles Prepared by the Homogeneous Precipitation Method with a Mixed Solutionof Ethylene Glycol and Polyethylene Glycol

Cerium oxide (CeO₂) nanoparticles were obtained by heating a polyethylene glycol (PEG) solution of cerium nitrate hydrate [Ce(NO₃)₃ 6H₂O] at 383 K for 3 h. When the PEG, whose molecular weight was 20,000, was used for the preparation, the monodispersed CeO₂, whose particle size was about 102 nm, was obtained. When the mixture of PEG20,000 and ethylene glycol (EG) was used to prepare the PEG solution of cerium nitrate hydrate, the average particle size increased from 102 nm to 660 nm with an increase in the EG content of the solution. The pore structure in the obtained CeO₂ particles also depended on the weight ratio between EG and PEG20,000.