Titanium dioxide nanoparticles and nanostructures for photocatalytic applications

Titanium dioxide (TiO₂) is the most intensely investigated photocatalyst and until today the only one that has already been commercialized and that is involved in many applications such as self-cleaning materials, dye-sensitized solar cells, as well as water and air purification. Consequently, an exponential growth of research activities concerning the nanoscience and nanotechnology of TiO₂ has been observed during the last decades. These raising research activities have recently lead to the synthesis of nanosized TiO₂ nanoparticles and nanostructures with different shapes, morphologies and phase compositions. Thus, the present chapter focuses mainly on the synthesis of these nanomaterials. The thermodynamic stability, the transition between different TiO₂ polymorphs and the surface properties of these polymorphs are presented with the aim to utilize this information for a better understanding of the mechanism of the formation of TiO₂ nanomaterials. The photocatalytic applications of these TiO₂ nanomaterials are also discussed.