A novel foam combustion approach for the synthesis of nano-crystalline cobalt oxide powder

This article focuses on the nano-crystalline tricobalt tetraoxide (Co₃O₄) synthesis using the combustion method. The fabrication process involves the combustion a mixture of cobalt nitrate as oxidized and expanded polystyrene (EPS) as a novel fuel. The effects of fuel/oxidizer ratio on the phases formed, Co₃O₄ as a major phase and CoO as an impurity, and the Co₃O₄ crystallite size have been addressed. Based on the thermal analyses data (TGA and DTA), which follow the phase changes during the heat treatment of the parent fuel/oxidizer precursor, the different parent precursors have been calcined at 500?°C. Characterization of the formed solids has been performed using various tools (XRD, FT-IR, SEM, TEM, and XPS). It was concluded that the EPS content, in the combustion precursor mixtures, is a key parameter that controls the phase features of the prepared nanomaterials. CoO impurity was detected for the solids with EPS?>?4?wt%. The crystallite size, morphology, and the surface elemental concentration are influenced by changing the EPS content. The activity of the different powders towards hydrogen peroxide decomposition has been evaluated at the 35–50?°C temperature range.