Preparation of zinc oxide/silica nanocomposite particles via consecutive sol-gel and flame-assisted spray-drying methods

ZnO/SiO₂ nanocomposites were prepared using consecutive sol-gel and flame-assisted spray-drying methods. Zinc oxide and silica sols were prepared individually from zinc acetate and water glass, respectively, via a sol-gel method. Subsequently, zinc oxide sol, silica sol, and a mixture of both were spray dried in a flame reactor to generate powder of pure zinc oxide, pure silica, and a ZnO/SiO₂ nanocomposite, respectively, in order to compare the characteristics. The generated particles were characterized via luminescence spectrophotometer, Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to obtain the photoluminescence spectra, chemical bonding, crystallinity, and morphology of the particles, respectively. The photoluminescence emission recorded at 250nm excitation showed a peak at approximately 400nm that was characterized by a violet band. The highest intensity was shown by a 75mol% ZnO sample followed, in order, by 50mol% ZnO, 25mol% ZnO, and pure ZnO.