Nanophase materials, with their gram sizes or phase dimensions in the nanometer size regime, are now being produced by a wide variety of synthesis and processing methods. The interest in these new ultrafine-grained materials results primarily from the special nature of their various physical, chemical, and mechanical properties and the possibilities of controlling these properties during the synthesis and subsequent processing procedures. Since it is now becoming increasingly apparent that their properties can be engineered effectively during synthesis and processing, and that they can also be produced in quantity, nanophase materials should have considerable potential for technological development in a variety of applications.

Among these materials, one of the very important, is nanocrystalline anatase (TiO₂), widely used now for photocatalytic air and water purification and many other purposes based on photocatalytic oxidation and decomposition of organic pollutants. The material can be also used for solar energy storage and conversion, organic syntheses and etc. Titanium dioxide is one of the most popular and promising materials for these purposes, because of its stability, commercial availability and ecological safety. According to the literature, the photocatalytic activity of suspended TiO₂ in solution strongly depends on the physical properties of TiO₂ (e.g. crystal structure, surface area, surface hydroxyls, and particle size). In this respect, attempts have been made to prepare TiO₂ particles with high surface area, suitable porosity and a distinct shape (films, spheres, rods, etc.) in order to suit this material to the demands of its application. To achieve good photocatalytic activity, the material should contain as low as possible amount of amorphous material. Sufficient amount of surface OH^- groups is also needed in order to stabilize the active ion-hole pairs in the form of surface OH⁺ and O^2- radicals on the surface of the TiO₂ photocatalyst.