Panoscopic Assembling and UV‐Shielding Properties of Calcia‐Doped Ceria with Micaceous Lepidcrocite Type Potassium Lithium Titanate via Soft Chemical Processes

In order to attain further performance improvements concerning UV‐shielding, calcia‐doped ceria (Ce_0.8Ca_0.2O_1.8) nanoparticles were coated on micaceous lepidocrocite‐type potassium lithium titanate (K_0.8Li_0.27Ti_1.73O₄), 10–20 μm in diameter via soft solution processes, where the micaceous titanate was prepared by reacting K₂CO₃, Li₂CO₃ and TiO₂ using K₂MoO₄ flux at 950°C. After putting micaceous potassium lithium titanate particles in deionized water at 40°C, appropriate quantities of 3 M NaOH aqueous solution and 0.8 M CeCl₃‐0.2 M CaCl₂ mixed aqueous solution were simultaneously dropped, where the solution was stirred and pH was kept at 12 through the reaction. Then, the desired amount of 2 M H₂O₂ solution was added and pH was also kept at 12. The slurry was filtrated and washed with water and methanol. The precipitate was fired at 700°C for 1 h to obtain micaceous K_0.8Li_0.27Ti_1.73O₄ coated with white Ce_0.8Ca_0.2O_1.8 nanoparticles. Such panoscopic assembling successfully improved the comfort of the product when wearing it on the skin without compromising the UV‐shielding ability, meanwhile greatly reducing the oxidation catalytic activity.

Keywords:

• calcia‐doped ceria
• plate‐like titanate
• composite
• UV‐shielding ability
• comfort of the product
• oxidation catalytic activity

This research was carried out as one of the projects of the MSTEC Research Center at IMRAM, Tohoku University and was partially supported by the Ministry of Education, Culture, Sports, Science and Technology, Scientific Research of Priority Areas “Panoscopic Assembling and High Ordered Functions for Rare Earth Materials” and the JSPS Asian Core Program “Interdisciplinary Science of Nanomaterials”.