Low-Temperature Synthesis of Flower-Shaped CuO Nanostructures by Solution Process:  Formation Mechanism and Structural Properties

Flower-shaped CuO nanostructures have been prepared by the simple solution process at 100 °C using copper nitrate, NaOH, and hexamethylenetetramine (HMTA) for 3 h without the use of any complex reagents. The morphological investigations by field emission scanning electron microscope (FESEM) revealed that the flower-shaped nanostructures are monodispersed in large quantity and exhibit the nanocrystalline nature with monoclinic structure. The flower-shaped morphologies are strongly dependent on the concentration of HMTA, presence or absence of NaOH and HMTA, and reaction time. The possible growth mechanism for the formation of flower-shaped CuO products was also discussed in detail.