ZnO/SiO₂ nanocomposite cryogels prepared by vacuum freeze drying

In recent years, ZnO/SiO₂ nanocomposite thin films have attracted much attention for a wide range of device applications based on their specific optical and electrical properties. Traditionally, the ZnO/SiO ₂ nanocomposites were prepared at the form of thin film because the ZnO/SiO₂ nanocomposite gels are difficult to synthesize. Therefore, in the present study, a novel route of the mixed ZnO/SiO₂ nanocomposite cryogels were prepared by sol-gel technology and dried by vacuum freeze drying. The wet gels were synthesized by co-precursor method with the precursors containing tetraethoxysilane [Si(OC2H5)4,TEOS] and zinc acetate [Zn(CH₃COO)₂.2H₂O]. After vacuum freeze drying, the nanocomposites were annealed at different temperature. The properties of the resulting ZnO/SiO₂ nanocomposite cryogels were characterized using Scanning Electron Microscopy (SEM), nitrogen absorption/desorption isotherms, thermogravimetric and differential scanning calorimeter (TG-DSC).