In situ growth approach for preparation of Au nanoparticle-doped silica aerogel

Gold (Au) nanoparticle-doped silica aerogels were prepared via the in situ growth approach. The Au ions were reduced to Au nanoparticles by hydroxylamine during the prehydrolysis oligomer process. Then, the samples were followed through with continuous supercritical extraction with CO2. Ultraviolet–visible (UV–Vis) spectrophotometry was employed following the reduction of Au ions and the growth of Au nanoparticles. The size of the Au particles at the inner surface of the silica aerogel was within the 5–7 nm range. The morphology and microstructure characteristics of both silica aerogel and Au-doped samples were obtained through SEM, HRTEM, BET, and BJH. The total pore volume of obtained aerogel ranged within 2.9–3.45 cm−3/g, and the mean pore diameter was about 15 nm.