Facile synthesis of Cu-SiO2 composite aerogels and its application as supporting materials for erythritol-based shape-stable phase change materials

Silica-based functionalized composite aerogels possess the merits of high porosity and versatile properties, and can be utilized as a matrix for lots of applications including shape-stable phase change materials (SSPCMs). In-situ functionalization of silica-based aerogel, which can avoid challenges related to the dispersion of functional filler, presents a valuable but less-explored strategy. Herein, metallic copper-functionalized silica (Cu–SiO 2 ) aerogels were synthesized by co-condensing tetraethyl orthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of copper acetate via an ambient pressure drying procedure followed by thermal reduction. The Cu 2+ was initially coordinated to the amino groups in APTES and in-situ anchored on the aerogel skeleton, which was then thermally reduced to metallic copper to fulfill the in-situ functionalization. Erythritol (ET) was then vacuum impregnated into the Cu–SiO 2 aerogels to obtain SSPCMs. The prepared SSPCMs exhibited a high ET loading of 86.9%, corresponding to a high latent heat of 307.5 J g −1 , and reduced supercooling. When the aerogel framework contained 3.46 wt% copper, the thermal conductivity of the SSPCM increased by 83.03% compared with that of pure ET. The SSPCM also showed a photothermal conversion efficiency of 71.82% due to the local surface plasmon resonance effect of metallic copper and the multidirectional light-scattering paths provided by the aerogel. In addition, the SSPCMs exhibited excellent thermal reliability over 100 melting/solidification cycles. Overall, this work presents a novel strategy for the preparation of functionalized silica-based composite aerogels and obtained a novel SSPCM for latent heat storage and solar thermal applications.