Synthesis of ZnO nano-powders via a novel PVA-assisted freeze-drying process

Abstract

Zinc oxide (ZnO) nano-powders were prepared by a simple PVA-assisted freeze-drying process. Porous materials were firstly prepared by freeze-drying of polyvinyl alcohol (PVA) and zinc nitrate aqueous solutions with different mass ratios, and then calcined to produce ZnO nano-powders directly. PVA was applied as a polymeric carrier and its interaction with zinc nitrate was investigated for its effects on the morphology of the obtained ZnO nano-powders. The PVA/Zn(NO₃)₂ foams were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The obtained ZnO nano-powders were also characterized using various techniques and were evaluated as photocatalysts for dye degradation.