In-situ synthesis and attachment of colloidal ZnO nanoparticles inside porous carbon structures
Résumé
A simple hydrothermal impregnation process enabling functionalization of carbon foams by attachment of nanostructured ZnO with flower-like morphology to control the interface interactions with some sugar alcohols based phase-change materials for thermal energy storage applications was developed. The process involves decomposition of urea in hydrothermal solution, formation of Zinc Carbonate Hydroxide Hydrate (ZCHH) as major solid phase and zinc hydroxide as minor phase, attachment of zinc carbonate hydroxides and zinc hydroxides to the carbon substrate and their decomposition on the inner walls of carbon foam by thermal treatment at temperatures in the range 250-400 degrees C producing ZnO nanoparticles. The zeta potential of complex ZCHH particles with and without dispersants adsorbed on particles' surfaces was studied. The results show that, during hydrothermal synthesis process, negative charges of hydroxylated zinc species are formed on the surface of tetrahedral ZHCC crystal habit that enable interactions with positive charges from the inner surface of the carbon foams.