PHOTOCATALYST AND PROCESS FOR THE PREPARATION THEREOF

摘要

Incorporating fluorine into a photocatalyst layer made of an oxide semiconductor such as titanium oxide serves to enhance the photocatalytic activity of the oxide. The photocatalyst may take in itself the form of film, flake, particle, powder or fiber. Alternatively, it can be used in a state applied on the surface of a substrate taking the form of plate, film, flake, particle, rod, fiber or the like. When the substrate has an alkali-containing glass composition, forming a layer of a metal oxide, such as silicon oxide, containing fluorine as the fluorine-containing layer between the substrate and a photocatalyst layer serves to protect the photocatalytic activity of the photocatalyst layer from lowering caused by the diffusion of alkali metal ions (such as Na ion) of the glass substrate into the photocatalyst layer, because the metal oxide layer functions as alkali barrier. Supported photocatalysts prepared by using an inorganic fiber or glass sheet as the substrate have an extremely excellent decomposition power against dilute harmful organic gases, thus being useful as the wall covering and air filters for the clean closed space and clean closed transfer space for semiconductors, various clean rooms, office buildings and general housing, and being effective in air cleaning of room, destruction of microorganisms, inhibition of stain, protection of transparent panels from misting (retention of hydrophilicity) and so on.