A comprehensive study on ZrO2-ZnO nanocomposites synthesized by the plant-mediated green method

Abstract

Zirconia—zinc oxide (ZrO2-ZnO) nanocomposites with three different amounts of zirconia (ZrO2) contents (5%, 10%, and 15%) were successfully synthesized using the leaf extract of Azadirachta indica (also known as Neem). The prepared nanocomposites were examined from the microstructural and optical point of view. The existence of the mixed phase of hexagonal ZnO together with the tetragonal ZrO2 in each sample was confirmed by the X-ray diffraction data. Rietveld refinement was performed to determine the microstructural parameters. A significant morphological as well as microstructural change was also noticed from SEM and HRTEM images with the admixture of increasing quantities of zirconia. A characteristic metal oxide band within 1000 cm−1, was confirmed by the Fourier transform infrared spectroscopy. UV–visible spectra confirm the decrease in optical band gap energy values from 3.30 eV to 3.15 eV for the ZnO phase and from 3.93 eV to 3.73 eV for the tetragonal ZrO2 phase with the increasing amount of ZrO2 admixture into the ZnO host material. All of these findings would likely be useful not only in the manufacture of electronic and optical devices, but would also be useful for water purification through photocatalytic activities.