Synthesis and UV-shielding properties of silica-coated calcia-doped ceria nanoparticles via soft solution processes

Ahmed Mohamed El-Toni, Shu Yin, Yuichiro Hayasaka, Tsugio Sato

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16 Citations (Scopus)


White nanoparticles of calcia-doped ceria were prepared from the precipitate by reacting CeCl3-CaCl2mixed solution with NaOH solution at pH 12 and the oxidation with hydrogen peroxide solution at 40°C, followed by the calcination at 700°C for 1 h. The sample before calcination contained significant amount of OH- in the lattice and was yellow, but the powders calcined above 700°C were white, indicating that cation defect formed by replacing O2 - with OH- played as the color center. It is confirmed that calcia-doped ceria showed much lower photocatalytic activity as well as lower generation of singlet oxygen under UV light irradiation than those with titania and zinc oxide. Calcia-doped ceria particles were coated with amorphous silica by means of sol-gel reaction technique using hydrolysis of tetraethylorthosilicate (TEOS) or acid hydrolysis of sodium silicate. The silica coating by sol-gel reaction with TEOS was much more efficient for the reduction of catalytic activity of ceria for the oxidation of organic materials without loss of UV-shielding ability than that by acid hydrolysis of sodium silicate.

Original languageEnglish
Pages (from-to)9-14
Number of pages6
JournalJournal of Electroceramics
Issue number1
Publication statusPublished - 2006 Sep


  • Calcia doping
  • Ceria
  • Oxidation catalytic activity
  • Silica coating
  • UV-shielding

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering
  • Materials Chemistry


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