Dependence of the microstructural properties of ZnO particles on their synthesis

The influence of experimental conditions on the precipitation of ZnO particles and their microstructural properties has been investigated using X-ray powder diffraction, Fourier transform infrared spectroscopy and thermal field emission scanning electron microscopy. Mixing of ZnCl2 or Zn(ac)2 solution with Na2CO3 solution of proper concentrations yielded aggregates of fine Zn5(CO3)2(OH)6 particles, which were converted to nanosize ZnO particles at 300 °C. The size of these ZnO particles increased to around 100 nm upon heating at 600 °C, whereas a small fraction of them turned out in the form of aggregates. The obtained ZnO particles assumed a pseudospherical shape; however, their basic structure was based on the hexagonal space group. Precipitation of Zn2+ ions in decomposing HMTA at 90 °C yielded ZnO particles around micron range. Crystalline Zn(OH)2 was not detected in the precipitates. ZnO particles obtained by this method were strongly elongated in the direction of the crystallographic c-axis.