Synthesis and UV-shielding properties of metal oxide doped ceria via soft solution chemical processes

Ultrafine particles of M²⁺ doped ceria (M²⁺=Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺) for use as a UV filter have been prepared via soft solution chemical routes at 40°C. X-ray diffraction revealed that the prepared doped particles had cubic fluorite structures, although the peak positions changed depending on the kind and amount of the doped metal ion. Doping with 20 mol% Ca²⁺ and 20 mol% Zn²⁺ resulted in a considerable decrease in the particle size (2-4 nm) and catalytic activity of ceria for oxidation of castor oil. CaO doped cerium dioxide showed excellent UV absorption and transparency in the visible ray region compared with undoped cerium dioxide.