Preparation and UV-shielding Properties of Silica-coated Ceria Nanocomposite

Tsugio Sato, Shu Yin, Yoshinobu Fujishiro, Kei Hasegawa, Ruxing Li, Shinryo Yabe

Research output: Contribution to journalArticlepeer-review

Abstract

Nanoparticles of calcia doped ceria coated with amorphous silica were prepared for UV shielding via soft solution chemical routes at 40-90°C. About 20mol% of CaO could be alloyed with ceria. Doping with calcia resulted in extremely decreasing the particle size (2-4nm), and consequently increasing UV light (λ <400nm) absorbing capacity and transparency in the visible ray region (λ >400nm). Coating ceria with less than 20 mass% amorphous silica resulted in the decrease in the ceria content, but no noticeable decrease in the UV-shielding ability probably because of the depression of the powder agglomeration. The oxidation catalytic activity of ceria was effectively depressed by both doping with calcia and coating with amorphous silica. The photocatalytic activity of undoped and doped CeO2 was much lower than that of TiO2 and ZnO. The generation of singlet oxygen on CeO 2 with UV irradiation in air was also lower than that on TiO 2 and ZnO and was greatly decreased by doping with CaO. There was a clear advantage with CaO doped CeO2 coated with amorphous silica compared with other inorganic UV filters because of its excellent UV-absorption capacity, high transparency in visible light and low photocatalytic activity which may safely supply high sun protection factor (SPF) with natural appearance.

Original languageEnglish
Pages (from-to)107-112
Number of pages6
JournalFuntai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
Volume51
Issue number2
DOIs
Publication statusPublished - 2004 Feb

Keywords

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

ASJC Scopus subject areas

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Metals and Alloys
  • Materials Chemistry

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