2D spinodal phase-separated TiO2 films prepared by sol–gel process and photocatalytic activity

For the purpose of obtaining oxide thin films with high photocatalytic activity, we have successfully prepared the TiO2 anatase polycrystalline films with a two-dimensional spinodal phase-separated structure (2D-SPSS) in micron size by the sol–gel dip-coating method from a titanium tetraisopropoxide solution containing polyoxyethylene(20) nonylphenyl ether. It has been also found that TiO2 films with a variety of morphologies in addition to the 2D-SPSS can be formed by controlling the molar ratio of water to titanium tetraisopropoxide. The methylene blue photodegradation activity of the 2D-SPSS TiO2 film was higher than that of dense TiO2 film prepared from a TiO2 sol without co-existing polymer. This fact can be interpreted in terms of possessing a high specific surface area available for the photocatalytic reaction.