Synthesis of broad-spectrum UV-shielding plate-like titanate/calcia-doped ceria composite in different pH solution

In order to improve the comfort when applied on skin without compromising the ultraviolet (UV)-shielding ability of calcia-doped ceria (Ce1−xCaxO2−x) (donated as: CDC) nanoparticles, the inorganic composite composed of plate-like potassium lithium titanate (K0.8Li0.27Ti1.73O4) (donated as: PLT) substrate coated with CDC nanoparticles was prepared by a wet chemical method at different solution pH values. Here, PLT possessing UV-shielding ability were used to improve the comfort and covering ability of CDC. The isoelectronic points (IEP) of PLT and CDC were pH 2.5 and ca. 7, respectively, indicating the electrostatic attraction between negatively charged PLT substrate and positively charged CDC nanoparticles can be expected at pH between 2.5 and 7. The PLT/CDC composites with different CDC contents were prepared at pH 6.5 and 12.0 with and without hetero coagulation. The broad-spectrum UV-shielding material with good comfort and low oxidation catalytic activity was successfully synthesized by the combination of PLT and CDC. The influence of pH on the properties of PLT/CDC was evaluated.