Using ZnSO_4 and urea as raw materials, nanometersized ZnO was prepared at 90 ℃ by homogeneous precipitation method. The effects of reaction temperature, reaction time, concentration and the ratio of the materials on the formed nanometer ZnO were also discussed. The XRD reveals that the ZnO has a hexagonal structure. The TEM observation indicates that the ZnO is spherical particles with the average diameter of 20 nm. IR and TG-DTA were also used to characterize the nanometer ZnO. The UV absorption properties were detected by the UV spectrophotometer. The results show that the nanometer ZnO has an extremely strong absorption at 200～380 nm wavelength and also a relatively strong absorption at visible region. Photodegradation of dyes in aqueous solution was investigated by using this nanometer ZnO as a photocatalyst, showing that after 60 minutes of solar illumination, the decolorization rate of the acidic red 4BE can be 100%.

Key words: ZINC OXIDE, NANOPHASE MATERIALS, PHOTOCATALYSIS, LIGHT ABSORPTION, DYES, DEGRADATION, STRUCTURE CHARACTERISTICS