Synthesis of cauliflower-like ZnO through hydrothermal methods

The cauliflower-like ZnO nanorod clusters, radial short/long nanorods and whisker clusters have been prepared via simple hydrothermal method at 180°C by using zinc salts and hydrazine hydrate (N₂H₄ · H₂O). The microstructures of the as-synthesized samples have been studied by means of X-ray diffraction, scanning electron microscope, field-emission scanning electron microscope and high-resolution transmission electron microscopes. The mean sizes of as-grown nanorods or whiskers are about 100 nm, 200 nm and 1 μm in diameter, respectively. The formation of ZnO nanorod or whisker clusters and the importance of N₂H₄ · H₂O concentration are discussed with growth unit model of anion coordination polyhedra.