Facile synthesis, characterization, and microwave absorbability of CoO nanobelts and submicrometer spheres

Single crystal CoO nanobelts with thicknesses of several nanometers and widths of 30-100 nm and polycrystalline CoO submicrometer spheres self-assembled by nanoparticles with diameters ranging from 20 to 40 nm were synthesized via a microemulsion method under solvothermal conditions. The shape and size of CoO nanostuctures can be well controlled by H ₂O/surfactant molar ratio and other solvothermal parameters. Apart from structural and morpholoical characterizations of the submicrometer spheres and the nanobelts, powder X-ray diffraction, electron microscopy techniques, and microwave absorption properties of typical samples have also been investigated. The results indicate that the microwave absorption of nanobelts is stronger than that of submicrometer spheres.