Preparation and characterization of ZnO/SiO2@n-octadecane nanocapsule for ultraviolet absorbing and photothermal conversion energy storage

In this work, PCM nanocapsules composed of ZnO/SiO 2 shell and n-octadecane core were successfully synthesized by emulsion polymerization and hydrothermal method . The crystallinity of ZnO was enhanced on the SiO 2 shell by MPTS modification. The granule-like ZnO were distributed on the SiO 2 shell. The encapsulation rate of n-octadecane in nanocapsules was about 45.2 % with enthalpy of 95.0 J/g melting at room temperature 28.3 °C. Furthermore, due to the presence of ZnO, the synthesized PCM nanocapsules had excellent UV absorption properties for whole wavelengths, and the absorbed UV light can be converted into heat energy for storage, and the photothermal conversion efficiency had reached 25.0 %. Hence, the prepared ZnO/SiO 2 @n-octadecane nanocapsules had broad application prospects due to its thermal energy storage , UV protection and photothermal conversion performance.