Controlling the size and morphology of TiO2 within micron-size

could help to carry out the idea that TiO2 photocatalyst can be easily recycled with remarkable photocatalystic property. Micron-size titanium dioxide(TiO2) flaky crystal was synthesized by means of a simple template-free hydrothermal method using rutile TiO2 as raw material. Then the morphology and crystalline structure of the obtained samples were characterized by using scanning electron microscope(SEM)

X-ray diffraction(XRD) and N2 adsorption / desorption methods. TiO2 flaky crystal showed a length of 60—80 μm

width of about 30—60 μm and thickness of 4—9 μm. The XRD peaks attributed to H2Ti4O9·H2O after hydrothermal reaction

while turned to bi-phase TiO2 by calcination. The BET surface areas and pore sizes are 68 m2·g-1

244 m2·g-1 and 21.6 nm

10.4 nm with or without calcined

respectively. The formation mechanism of TiO2 flaky crystal was also speculated based on the experimental results. The photocatalytic performance of the calcined samples was tested in the degradation of the methyl orange(MO)

under UV light irradiation. For comparison

Degussa P25 powder was used as a reference catalyst. The calcination temperature obviously influenced the UV light photocatalytic activity of the TiO2 samples. In particular

the flake-like bi-phase TiO2 obtained by calcination treatment at 450℃ exhibits the highest photodegradation efficiency of MO. Results indicated that exposing the solution of MO with the catalyst for 30 min

a decomposition degree 92.4% was obtained

and after 60 min the dye was almost totally decomposed. The TiO2 flaky crystal presented here performed as practical photocatalysts for water purification

as it can be easily recycled in the shape of the large grain size.