Studies On Photocatalytic Properties Of Nano-TiO₂

Many solids have been used as photocatalysts, but the best one has been found to be TiO₂. TiO₂ and metal-doped TiO₂ are of a variety of applications such as photo-oxidation of organic molecules in aqueous solutions or sterilization. Anatase is the most efficient one by a photocatalytic point of view and in particular to photodegrade organic species in liquid-solid systems. Among various preparation methods for TiO₂, the Sol-Gel technique appears to be very interesting because it allows one to obtain very small and highly activity TiO₂ nanocrystals. The pure and Fe³⁺-doped (0.25, 0.75 and 1% in Fe) TiO₂ nanocatalysts were prepared by Sol-Gel processing, and characterized by DTA, XRD, TEM, IR. The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue and photocatalytic degradation of organism in waste water. The results indicate that the concentration of Fe³⁺ dopant does not influence the crystal structure of the nanocatalysts, but significantly affect their photocatalytic activity. Catalysts with the Fe show a considerably better catalytic behavior than non-doped TiO₂. The best efficiency for photocatalytic degradation of methylene blue was obtained by the 0.75at.% Fe³⁺-doped TiO₂ nanocatalyst, but The best efficiency for photocatalytic degradation of organism in waste water was obtained by the 1at.% Fe³⁺-doped TiO₂ nanocatalyst. The photocatalytic TiO₂ film on common glass has been made by dip-coating method. The results indicate that TiO₂ film has photocatalytic decomposition effects. TiO₂ was immobilized on expanded perlite material using the Sol-Gel process. The TiO₂/EP photocatalyst was prepared and applied to the degradation of methylene blue and degradation of organism in wasted water.