Sonochemical synthesis and characterization of Co3O4 nanocrystals in the presence of the ionic liquid [EMIM][BF4]

For the first time, a sonochemical process has been used to synthesis cobalt oxide Co3O4 nanoflowers and nanorods morphology in the presence of the ionic liquid 1-Ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] as reaction media and morphology template. Different sonication time periods and different molar ratios of the ionic liquid (IL) were used to investigate their effects on the structural, optical, chemical and magnetic properties of the produced Co3O4 nanoparticles. During synthesis process brown powder contains cobalt hydroxide Co(OH)2 and cobalt oxyhydroxide (Cobalt hydroxide oxide) CoO(OH) was formed, after calcination in air for 4 h at 400 °C a black powder of Co3O4 nanoparticles was produced. The produced Co3O4 nanoparticles properties were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), transmission electron microscopy (TEM), FTIR spectroscopy, UV-vis spectroscopy, and Vibrating Sample Magnetometer (VSM). To explain the formation mechanism of Co3O4 NPs some investigations were carried on the brown powder before calcination.