Sol-gel synthesis and characterization of ZnO-SiO₂ nanocomposites: a comparative study with pure ZnO and SiO₂

In this investigation, pure SiO₂, ZnO, and ZnO-SiO₂ (10 : 90) nanocomposites were synthesized via the sol-gel method and systematically characterized in a comparative framework. Upon increasing the annealing temperature, the ZnO-SiO₂ composite predominantly retained its amorphous character, with the emergence of distinct ZnO diffraction peaks. Structural analysis using X-ray diffraction (XRD) confirmed the presence of the wurtzite phase in ZnO, alongside the intrinsically amorphous nature of the SiO₂ matrix. Fourier-transform infrared (FT-IR) spectroscopy provided clear evidence for the formation of Zn-O-Si bonds, in addition to the characteristic Si-O-Si and Zn-O vibrational modes. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) revealed a homogeneous elemental distribution within the synthesized nanocomposite. This work underscores the pronounced influence of thermal treatment on interfacial structure and crystallinity, offering insights into the tailored design of ZnO-SiO₂ nanocomposites through controlled annealing.