Synthesis of ZnO Nanoparticles and Investigation of the Ionic Template Effect on Their Size and Shape

Nanorods of ZnO have been selectively produced in a simple aqueous system prepared by mixing Zn(NO3)2 and NaOH solutions. Also, semi-spherical ZnO nanoparticles have been obtained by adding KNO3 and K2SO4 solutions to the Zn(NO3)2/NaOH mother solutions at different molar ratios of KNO3/Zn(NO3)2 and K2SO4/Zn(NO3)2, but with using LiNO3 at different molar ratios, the nano particles shape was different and not semi-spherical. The products have been characterized by X-ray diffraction (XRD) and FT-IR spectroscopy. The XRD patterns of samples were in agreement with that of the typical wurtzite structure ZnO and the sharp diffraction peaks indicated good crystallinity of the ZnO nanoparticles. The morphologies of the particles have been studied with a scanning electron microscope (SEM) and a transition electron microscope (TEM), and their average size has been determined by means of an X-ray line-broadening method using the Scherrer equation. The results showed that the presence of K2SO4, KNO3 or LiNO3 led to the formation of slightly smaller ZnO nanoparticles. Chemical component analysis by energy-dispersive spectroscopy (EDS) showed that the ZnO nanoparticles were free from impurities.