Template-free hydrothermal synthesis of Flower-like hierarchical zinc oxide nanostructures

Flower-like hierarchical zinc oxide nanostructures have been successfully synthesized by a facile and template-free hydrothermal method from zinc acetate (Zn(AC)₂) and potassium hydroxide (KOH) only. Furthermore, the effects of alkaline mineralizer type on product synthesis by hydrothermal processing have been studied. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscope, UV–vis spectrophotometry and Raman-scattering spectroscopy. When the type of mineralizer was KOH, the shape of ZnO sample has presented flower-like hierarchical nanostructures with diameters of 2–4 μm. Photocatalytic activity of the hierarchical ZnO nanostructures was evaluated by the degradation of methylene blue (MB) under UV light illumination. The as-prepared ZnO nanostructures exhibited a significantly enhanced photocatalytic activity than commercial ZnO. This was mainly attributed to the unique morphology and higher surface area.