|TiO2 normally exists in small quantity as a powder and thus is used as a suspension or fluid layer, but it is much wanted for handling purposes that it be affixed to a base material. In general, a comparatively thin smooth TiO2 film is prepared for pollution prevention and antibacterial purposes by coating a titanium alloy on a base material. The oxidizing power of TiO2, however, attacks also the base material, but by sandwiching an inorganic film between it and the base material, it can be applied to organic matter such as plastic. Already, driven by a growing need for environmental improvement with regards to odors in the living environment, a market is in the making with air purifiers having begun with home products and eventually evolved into commercial- use products, as cutting- edge products have been developed and launched one after another in 1998. Moreover, studies into applying the super hydrophilic property to dirt prevention are widespread, as some product launches such as antifogging back mirrors can be seen.|
However, in the treatment of massive amounts of comparatively high concentration pollutants, it is important to secure a fast reaction speed and a large area for coming in contact with gas. A thick film of large specific surface area has been developed by fixing TiO2 powder with a binder. In the case of nitrous oxides discussed in the next section, fluorine resin sheets, Macrodefect- Free cement and sol- gel paints are effective, the common feature of these materials being a porous structure.