Study of physical properties of cobalt oxide (Co3O4) nanocrystals

Cobalt oxide nanocrystals of size 10–15 nm have been prepared by a simple co-precipitation method. The structural investigations have been performed with X-ray diffraction and Transmission Electron Microscopy. Specific surface area of the nanocrystals is 77.5 × 104 cm2/g which have been calculated by X-ray diffraction data. Optical properties are discussed with UV/visible spectroscopy which shows the multiple band gap energies 2.28 eV (O− II → CoII) and 1.57 eV (O− II → CoIII) which suggest the possibility of degeneracy of the valence band. The magnetic behavior is investigated using Vibrating Sample Magnetometer. The Co3O4 nanocrystals possess paramagnetic character at room temperature.