A silica aerogel synthesized from olivine and its application as a photocatalytic support

This study investigates the performance of a silica aerogel-based air purifying coating to functionalize building materials. The air-purifying function comes from an increased photocatalytic activity when the photocatalyst is supported on a silica network with a large specific surface area like silica aerogels. In this study, silica aerogel was first synthesized with a low energy-consumption method from olivine via ambient pressure drying and was applied as a support to load photocatalytic anatase crystals. The silica aerogel production includes sol-gel synthesis, ion-exchange, surface modification and ambient pressure drying. The produced silica aerogel obtained a high specific surface area (694 m2/g) and pore volume (2.99 cm3/g), with a uniform pore size distribution and mesoporous structure. Titania was loaded onto the prepared silica aerogel through a precipitation method. The resulting samples were characterized by measuring the conversion efficiency to oxidize nitric oxide under UV-light irradiation, nitrogen physisorption and FTIR. The silica aerogel coating with titania crystals had a photocatalytic activity of 99.6%, showing it to be a promising photocatalyst in the built environment.