Fabrication and Characterization of Nanoporous Co Oxide (Co3O4) Prepared by Simple Sol-gel Synthesis

Abstract

Cobalt oxide (Co₃O₄) nanorods were prepared by a simple co-precipitation method using ethanol solution of cobalt nitrate as precursor and cetyl trimethylammonium bromide (CTAB) as surfactant. Morphological properties of the nanoparticles were characterized. XRD measurement exhibited the structure of Co₃O₄ nanocrystals for annealed samples. The SEM images revealed that the particles changed from spherical shape to rod-like shaped by increasing annealing temperature. The TEM results exhibited that the size of cobalt oxide nanoparicles decreased from 25 nm for as-made particles to 50 nm for annealed samples with increasing temperature. The FTIR analysis confirmed the functional group presents in the cobalt oxide nanoparticles. The sharp peaks in FTIRspectrum determined the purity of Co₃O₄ nanoparticles and existence of Co-O group. Absorbance peak of UV-Vis spectrum showed the band gap energy of 3.69 eV corresponding to wavelength about 335 nm for as-prepared samples and the band gap energy of 3.49 eV corresponding to wavelength about 355 nm for annealed Co₃O₄ nanoparticles. The results of magnetic measurements indicated a good coercive field and saturation magnetism around 447.81 G and 17.295 emu g^-1, respectively.