The ultrasonic method is used to synthesize titanium oxidenanocrystals. Productions with different crystal-structure are generated by calcination at different high temperature. The silane-coupling reagent is used to construct a stable absorbance of eosin on TiO

2

. The results of Uv-Vis diffraction spectrum indicate that the bandgaps for anatase-production and mixed-structure-productions are 2.1eV and 2.0 eV respectively. But the eosin sensitized TiO

2

with mixed-structure has no activity in triethanolamine water solution because of small surface areas

while the anatase-structure photocatalyst has a comparatively high activity. It has an ap

parent quantum efficiency of 2.32% at 420 nm and 2.86% at 480 nm.