Impact of pH levels on the morphological, dielectric and impedance spectral behaviour of cobalt oxide nanomaterials

Abstract

Pure Co3O4 nanomaterials were synthesized by using Sol-Gel technique at various pH levels (7, 8 and 9). Morphological and structural analysis was done by X-ray diffraction method (XRD), scanning electron microscope (SEM) and energy-dispersive spectroscopy EDX. The X-ray diffraction patterns revealed that the prepared samples crystallized in a cubic structure without any impurities. SEM micrographs validated the influence of pH in altering the morphology of the synthesized compound. The elemental spectrum analysis EDX confirms the presence of cobalt and oxygen without any impurities. Variation of dielectric constant, dielectric loss and impedance were analyzed for various temperatures and different pH values. Dielectric loss value increases at high temperature due to the thermal disturbance of the atoms. Cole-Cole impedance plot gives the information about grain and grain boundaries. DC electrical conductivity values of Co3O4 nanomaterials in the temperature range 40ºC to 250ºC increases with increase in pH level from 7 to 9. Arrhenius plot of Co3O4 nanoparticles confirmed that the activation energy at various temperature increases with increase in pH levels upto 8, then decreases for pH level 9.