Solvent mediated morphological control of aniline stabilized cobalt oxide nanoparticles

Cobalt oxide nanoparticles were synthesized by gamma radiation of solutions of cobalt ions. Pure isopropyl alcohol (IPA) and mixtures containing water were used as solvents. The morphology of the product is observed to be strongly influenced on varying the solvent system as noticed from the micrographs. Pure isopropyl alcohol effected the formation of cobalt oxide nanofibers while 20% IPA–water mixtures yielded nanospheres with a core–shell-like structure. Surfactants such as cetrimide (CTAB) and tetra ethyl ammonium bromide (TEAB) were added as structure directing agents and aniline was used as a stabilizer. However, the morphology was seen to be influenced significantly by the solvent system rather than the surfactants. The size distribution is affected by the presence of surfactants. The formation of oxide phase was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis. Co3O4 is observed to be the predominant oxide phase.