Synthesis of cerium phosphate white pigments from cerium carbonate for cosmetics

Abstract

Catalytically active cerium dioxide is used as light reflection materials for cosmetic applications. In fact, cosmetics containing this pigment cause too much oxidation on the skin. Therefore, the substitute for cerium dioxide is required to prepare the cosmetics without catalytic activity. Herein, as novel white pigments for use in cosmetics, cerium phosphates were prepared from cerium carbonate with hydrothermal treatment. The chemical composition (X-ray diffraction pattern and Infrared spectrum), powder properties (scanning electron microscopy images and particle size distributions), the photo and oxidation catalytic activity, color phase (ultraviolet-visible reflectance spectra and L*a*b* values), and smoothness of the cerium phosphates were evaluated. The photocatalytic activity of the samples was assessed from the decomposition of methylene blue. The oxidation catalytic activity of samples was estimated with ascorbic acid solution. All samples prepared in this work indicated X-ray diffraction pattern of cerium phosphate hydrate. Samples prepared in this work had no photo and oxidation catalytic activities. They indicated the absorption at 300–330 nm and high reflectance within the range of visible light. Because samples indicated higher L* values than 89, these materials are possible to use as white pigments. All materials prepared in this work had higher smoothness than cerium oxide.