Impact of Diverse Parameters on the Physicochemical Characteristics of Green-Synthesized Zinc Oxide-Copper Oxide Nanocomposites Derived from an Aqueous Extract of Garcinia mangostana L. Leaf

Compared to conventional metal oxide nanoparticles, metal oxide nanocomposites have demonstrated significantly enhanced efficiency in various applications. In this study, we aimed to synthesize zinc oxide-copper oxide nanocomposites (ZnO-CuO NCs) using a green synthesis approach. The synthesis involved mixing 4 g of Zn(NO3)2·6H2O with different concentrations of mangosteen (G. mangostana) leaf extract (0.02, 0.03, 0.04 and 0.05 g/mL) and 2 or 4 g of Cu(NO3)2·3H2O, followed by calcination at temperatures of 300, 400 and 500 °C. The synthesized ZnO-CuO NCs were characterized using various techniques, including a UV-Visible spectrometer (UV-Vis), photoluminescence (PL) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD) analysis and Field Emission Scanning Electron Microscope (FE-SEM) with an Energy Dispersive X-ray (EDX) analyzer. Based on the results of this study, the optical, structural and morphological properties of ZnO-CuO NCs were found to be influenced by the concentration of the mangosteen leaf extract, the calcination temperature and the amount of Cu(NO3)2·3H2O used. Among the tested conditions, ZnO-CuO NCs derived from 0.05 g/mL of mangosteen leaf extract, 4 g of Zn(NO3)2·6H2O and 2 g of Cu(NO3)2·3H2O, calcinated at 500 °C exhibited the following characteristics: the lowest energy bandgap (2.57 eV), well-defined Zn-O and Cu-O bands, the smallest particle size of 39.10 nm with highest surface area-to-volume ratio and crystalline size of 18.17 nm. In conclusion, we successfully synthesized ZnO-CuO NCs using a green synthesis approach with mangosteen leaf extract. The properties of the nanocomposites were significantly influenced by the concentration of the plant extract, the calcination temperature and the amount of precursor used. These findings provide valuable insights for researchers seeking innovative methods for the production and utilization of nanocomposite materials.