Preparation and evaluation of Au nanoparticle–silica aerogel nanocomposite

• TMOS/ethanol solution was gelled together with Au nanoparticles.
• The wet gel was dried in supercritical carbon dioxide.
• The characteristics of the original aerogel were maintained in the nanocomposite.
• The characteristics of Au nanoparticles were maintained in the aerogel nanocomposite.

A Au nanoparticle–silica aerogel nanocomposite was prepared by the gelling of a tetramethyl orthosilicate (TMOS)/ethanol solution together with Au nanoparticles and drying the wet gel in supercritical carbon dioxide. The aerogel nanocomposite contained Au nanoparticles at a concentration of 0.268 ppm. The bulk density, porosity, and specific surface area of the obtained nanocomposite were 0.126 g/cm3, 94%, and 890 m2/g, respectively. The nanocomposite was reddish-violet in color and transparent, and had a relative permittivity of approximately 6 with a dielectric loss of ca. 1 × 10−3 in the range of 10 MHz to 1 GHz.