Nanocrystalline Co sub(3)O sub(4) fabricated via the combustion method

A facile and rapid combustion method has been used to prepare nano-crystalline Co sub(3)O sub(4) spinel employing urea as a combustion fuel. The fabrication was carried out by refluxing a mixture of cobalt nitrate and urea followed by calcination, for 3 h in static air atmosphere, at 400 degree C. The thermal genesis of the Co sub(3)O sub(4) was explored by means of thermogravimetric and differential thermal analyses in air atmosphere in the temperature range 25-1000 degree C. X-ray diffraction, Fourier transform infrared spectra, and scanning electron microscopy were used to characterize the structure and morphology of the Co sub(3)O sub(4). The obtained results conrmed that the resulting oxides were comprised of pure single-crystalline Co sub(3)O sub(4) nanoparticles. Moreover, various comparison experiments showed that several experimental parameters, such as the reflux time and the urea/cobalt nitrate molar ratio, play important roles in the crystallite size as well as the morphological control of Co sub(3)O sub(4) powders. Consequently, the minimum crystallite size can be obtained at 12 h reflux and a urea/cobalt nitrate molar ratio of 5.