Sol-Gel synthesis, characterization and photocatalytic activity of Cobalt doped ZnO nanoparticles

Abstract

In the current study, Cobalt (Co) doped ZnO nanoparticles with different dopant concentrations are prepared using the sol-gel process. All the synthesized samples are characterised using a variety of instrumentation methods including XRD, FT-IR, UV-vis absorption spectroscopy, FE-SEM, EDAX, HRTEM and XPS. The XRD measurements revealed the crystallite sizes of the fabricated samples are reduced by increasing cobalt concentrations. The various functional groups present in the doped materials are identified using FT-IR spectra. According to the UV-vis absorption study, as Co dopant concentration rises, the energy band gap narrows down in comparison to pure ZnO. According to an FESEM image, Co doping in ZnO causes a shift in the morphology of the material, making for structures that resemble flowers almost exactly. The various elemental compositions are evaluated using EDAX. The results of analyses employing high-resonance transmission electron microscopy show that the two co-doped ZnO crystallites combine to produce spherical structures with a mean size of 16 nm. This is consistent with the crystallite size predicted by Scherrer's formula. According to the results of the XPS analysis, the Co ion was integrated into the ZnO lattice in a Co2+ oxidised form. The 0.3M Cobalt doped sample showed improved photocatalytic reaction efficiency of methylene blue. As the Co doping concentrations increased, the photocatalytic reaction's efficiency also increased.