Zinc Oxide Nanostructures and Their Morphology Depended Optical, Crystalline and Photocatalytic Properties

Zinc oxide nanostructures were synthesized via a simple wet-chemical method with the aid of aqueous ammonia. The prepared samples were characterized by scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction analysis, UV-visible absorption spectroscopy and photoluminescence spectroscopy. The scanning electron microscopy reveals the materials exhibit pillar and spherical like morphology. X-ray diffraction technique confirms the hexagonal wurtzite phase and crystal size from 38 to 66 nm of ZnO nanomaterials. UV-Diffusion reflectance spectra confirmed that the absorption was below 390 nm in near visible region. In addition, band gap energy measured by Tauc's plot relation was found to decrease from 3.07 to 3.00 eV. The photoluminescence spectra explain the photochemical emission observed at 420 and 440 nm. The photocatalytic activity of synthesized ZnO nanomaterials was investigated by photocatalytic degradation of congo red as a model dye pollutant under visible-light irradiation. The ammonia concentration significantly influences on morphology formation. The crystalline, optical and photocatalytic properties of synthesized materials strongly depends on its morphology.