Preparation of titanium dioxides in the W/C microemulsions and their photocatalytic activity

TiO2 nanoparticles were produced by controlled hydrolysis of TTIP in the W/C microemulsions stabilized by polymeric surfactants. The prepared particles were characterized using TGA-DTA, FT-IR, XRD, SEM and TEM. It was found that the residual hydroxyl group and the organic compounds were completely removed by calcination at 350°C and the amorphous phase transformed to an anatase structure above 420°C, though the particles dried at 105°C without calcination were amorphous. The crystallite size could be controlled by the water-to-surfactant mole ratio, W0, and the particle size increases from 8 to 18 nm with an increase of the W0 ratio. In addition, the photocatalytic activity decreases with an increase of the W0 ratio, though still higher than that of normal bulk TiO2.