Nanostructured cobalt oxides (Co3O4 and CoO) and metallic Co powders synthesized by the solution combustion method

The combustion synthesis technique using glycine and urea as fuels and cobalt nitrate as an oxidizer is capable of producing well-crystallized Co3O4, CoO, as well as metallic Co powders. An interpretation based on the thermodynamic viewpoint and the measurement of the combustion temperatures during the reactions occurring for various fuel-to-oxidant ratios was proposed for a study of the nature of combustion and its correlation with the characteristics of as-synthesized powders. The largest measured specific surface area of the powders was 36 m2/g at a 0.14 glycine-to-nitrate ratio. The crystallites were nano-sized ranging from approximately 23 to 90 nm.