Preparation of nanosized crystalline TiO2 particles at low temperature for photocatalysis

Nanocrystalline titanium dioxide (TiO2) particles were prepared by a modified alkoxide method under acidic conditions at temperatures ranging from 60degreesC to 90degreesC. The reaction temperature was used to control the crystalline phase of the TiO2 particles. At 60degreesC and 75degreesC rutile was formed whilst at 90degreesC anatase and brookite were formed. The photocatalytic activity of the prepared particles was tested for the degradation of sucrose. The photocatalytic activities of the prepared nanosized TiO2 were compared to those obtained from Degussa P-25 TiO2 as well as TiO2 crystalline samples prepared using the conventional sol-gel/heat treatment method. At low organic concentrations, Degussa P-25 exhibited higher photocatalytic behaviour than all the prepared particles while, at high organic concentrations, the nanosized TiO2 particles prepared at low temperature displayed an activity comparable to Degussa P-25 but much higher than the heat treated sample. The formation of excess intermediates during the degradation of higher sucrose loadings is believed to hinder the photoactivity of Degussa P-25, while the prepared TiO2 particles are able to maintain their activity for the degradation of the intermediates of sucrose.