ZnO nanowhisker clusters formed on Zn microspheres by wet chemical route

Urchin-like multi-dimensional ZnO nanowhisker clusters with or without void at the center of the structures have been constructed by a simple aqueous solution route to directly oxidize metallic Zn powder in concentrated NaOH solution with pre-existence of the zincate ions under various temperature conditions in a closed Teflon reactor. The morphology, size and structure of the ZnO nanowhiskers obtained under different temperature conditions have been observed in detail by field-emission scanning electron microscopy (FE-SEM). It has been found that various MD structures originate from different source and growth route. Formation mechanism of the urchin-like MD ZnO structures has been reasonably suggested on the basis of the experimental results. It is believed that the degree of supersaturation of the zincate ions in the solution plays a very important role in the process of controlling the nucleation and growth of the ZnO nanowhiskers as well as further oxidizing metallic Zn microspheres.