Surface characteristics and structural properties of sol-gel prepared ZnO-SiO2 nanocomposite powders

Zinc oxide-silica (ZnO-SiO2) composite powders with different surface morphologies were synthesized via sol-gel process using rice husk ash as silica source. Micrograph results revealed the surface modification of bare ZnOfrom hexagonal tips to hemispherical tips after incorporation of SiO2 to ZnO. After annealing at 400 and 500°C, the hemispherical tips became more apparent due to the removal of the flaky particles associated to the complexes of zinc. Annealing the sample powders to 600°C sharp tips was observed on the morphology of ZnO-SiO2. Infrared spectroscopy further support that SiO2 was incorporated to ZnOdue to the Si-O-Zn band observed in the IR spectra. X-ray diffraction results verify the presence of amorphous SiO2 and the polycrystalline nature of the samples having particle size in nanometer scale. Furthermore, diffraction spectra show that thermal annealing removes the zinc complexes resulting to more pronounced hemispherical tips of ZnO-SiO2.