Synthesis of MgO supported Co3O4 nanoparticles by a novel thermal decomposition approach and studies on their magnetic properties

An easy thermal decomposition approach for the synthesis of MgO supported cobalt oxide nanoparticles has been reported. Thermal decomposition of cobalt (II) acetylacetonate, in presence of the support in diphenyl ether at about 225 °C in air, followed by calcination at 350 °C leads to the formation of supported Co3O4 nanoparticles. The effect of using nanocrystalline MgO vs. macro-crystalline MgO as the support has been investigated. The supported cobalt oxide nanoparticles were characterized using a variety of analytical techniques including X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy and magnetic measurements. Nanocrystalline MgO acts as a better support compared to macro-crystalline MgO. EDXA results indicate higher loading of cobalt oxide nanoparticles on nanocrystalline MgO compared to macro-crystalline MgO (e.g. 17% Co vs. 7.4%). The crystallite size of cobalt oxide nanoparticles is smaller on nanocrystalline MgO compared to that on macro-crystalline MgO (28.1 nm vs. 41.3 nm) and also the mean particle size from transmission electron microscopy studies exhibits a similar trend (21.0 nm vs. 70.9 nm). Magnetic measurement studies indicate the absence of antiferromagnetic ordering in these materials and evidence for the paramagnetic defects has been observed at low temperatures.

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► Synthesis of MgO supported Co3O4 nanoparticles by a novel one step synthesis.
► Effect of nature of support (macro-crystalline/nanocrystalline MgO) investigated.
► Uniform dispersion of Co3O4 on nanocrystalline MgO compared to macrocrystalline MgO.
► Magnetic studies indicate the presence of Co3O4 nanoparticles on the supports.