Nanocrystalline CO3O^sub 4^ fabricated via the combustion method

A facile and rapid combustion method has been used to prepare nano-crystalline CO3O^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 °C. The thermal genesis of the CO3O^sub 4^ was explored by means of thermogravimetric and differential thermal analyses in air atmosphere in the temperature range 25â[euro]"1000 °C. X-ray diffraction, Fourier transform infrared spectra, and scanning electron microscopy were used to characterize the structure and morphology of the CO3O^sub 4^. The obtained results conrmed that the resulting oxides were comprised of pure single-crystalline CO3O^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 CO3O^sub 4^ powders. Consequently, the minimum crystallite size can be obtained at 12 h reflux and a urea/cobalt nitrate molar ratio of 5.[PUBLICATION ABSTRACT]