TiO2/SiO2 Films for Removal of Volatile Organic Compounds (VOCs) from Indoor Air

Abstract

Volatile organic compounds (VOCs) are the major pollutants in indoor air, which significantly impact indoor air quality and thus influence human health. A long-term exposure to VOCs will be detrimental to human health causing sick building syndrome (SBS). Photocatalytic decomposition of VOCs using TiO2 as a photocatalyst is a key technology for air cleaning devices because it can totally convert most VOC pollutants at low concentrations to harmless inorganic products at ambient temperature. UVA light required in the air cleaning device is nowadays a very cheap light source. A common approach to enhance the photocatalytic activity of TiO2 is also to increase its surface area (100–200 m2/g to 400–1000 m2/g). This can be achieved by immobilization of TiO2 on the porous supports such as porous silica and the preparation of such a catalyst in the form of a thin layer using an appropriate carrier. Porous silica is superior support for accommodating photocatalyst nanoparticles because it is chemically inert, possesses high surface area, is transparent to UV radiation, has great physical stability, and has hydrophobic character.