Complex impedance study on nano-CeO2 coating TiO2

Titanium dioxide (TiO2) nanoparticles and cerium dioxide (CeO2) nanoparticles coated titanium dioxide (TiO2) nanoparticles (CeO2-TiO2 nanoparticles) have been successfully synthesized by sol-gel method. The complex impedance of the materials was investigated. The grain resistance, boundary resistance and activation energy of the nanoparticles were calculated according to Arrhenius equation. According to calculating results, the active capacity of pure TiO2 nanoparticles has been improved because of nano-CeO2 coating. An optimal CeO2 content of 4.9 mol% was achieved. The high resolution electron microscopy images of CeO2-TiO2 nanoparticles showed that TiO2 nanoparticles, as a core, were covered by CeO2 nanoparticles. The average size of CeO2 coating TiO2 nanoparticles was about 70 nm. Scanning electron microscopy observation indicted that CeO2 nanoparticle coating improved the separation, insulation, and stability the CeO2-TiO2 nanoparticles, which was benefit to the activity of materials. (C) 2004 Elsevier Ltd. All rights reserved.