Fabrication of porous TiO2 film via hydrothermal method and its photocatalytic performances

Porous anatase (TiO2) films were fabricated onto stainless steel substrates with Ti(OC4H9)4 as a precursor via hydrothermal process. The crystallization and porous structure of TiO2 film were dependent on the time and temperature of the hydrothermal reaction. A TiO2 film with orderly porous structure and high crystallization was obtained upon treatment at 150 °C for 2 h. The grain size of TiO2 is ca. 6 nm, and pore diameter is ca. 10 nm. Diffusion of Fe into the porous TiO2 film occurred; Fe also diffused onto the surface of the film with the extension of hydrothermal reaction time or increase of the reaction temperature. The diffusion reaction has a large effect on the formation of porous TiO2 film as well as its interface texture. However, it does not change the crystal phase of the TiO2. The resultant TiO2 film showed high photocatalytic activity towards degradation of gaseous formaldehyde.