XU Xiaohong , LIU Shujie , WU Jianfeng , LI Xianxing , NI Yang

(School of Materials Science and Engineering, Wuhan University of Technology, Wuhan Hubei 430070, China)

Abstract: Various ZnO hexagonal column-like crystallites have been synthesized by hydrothermal method from zinc acetate and hexamethylenetetramine. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis spectrum were used to analyze the crystal phase, microstructure and the photocatalytic property. The influence of different reaction conditions on the morphology of ZnO and mechanism of ZnO crystal growth were discussed in this study. The results showed that ZnO morphology and crystal quality were influenced by the concentration and pH value of the solvent, the reaction temperature and the reaction time. For achieving good crystallinity of ZnO, the concentration and the pH of the solvent were 0.57mol/L and 6.0, the temperature was 97° C, and the time was 16h. The growth mechanism of the hexagonal column -like ZnO crystal is that the ZnO crystal nucleuses are formed by hydrolysis of zinc acetate and hexamethylenetetramine under appropriate hydrothermal condition. Since the (0001) face has faster growth rate than the other faces and the (0001) face can easily capture atoms, ZnO crystal nucleuses grow along the (0001) direction, which results in forming hexagonal column-like structure finally.

Key words:  hydrothermal method; hexagonal column-like ZnO; reaction conditions; morphology; growth mechanism