SILICA COATING ON THERMOCHROMIC VANADIUM DIOXIDE NANOPARTICLES FOR RADIATIVE COOLING

Abstract

(VO2@SiO2) nanoparticles (NPs) are effectively prepared at room temperature using pre-hydrolyzed 3-(mercaptopropyl) trimethoxysilane (MPTMS) coating in an alcohol-free aqueous solution. The regulated pre-hydrolysis of the silane precursor in water and the consequent condensation processes are crucial to achieving effective and consistent silica coating in aqueous solution on metal nanoparticles. The silica shell consistency is controlled by adjusting the duration of the coating. The silica shell can improve the optical and antioxidant properties of VO2 particles, which will be coated on films allowing higher luminous transmittance and a solar efficiency than the pure VO2 particles. This paper aims to test whether VO2 core are encapsulated by SiO2 shell through visual observation test where synthesized VO2@SiO2 nanoparticles changed from black to white colour, verifying that VO2 has been encapsulated with SiO2 shell. In addition, comparative analysis is conducted for different types of VO2@SiO2 nanoparticles to select the most suitable morphology for building application.