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

Abstract

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.