Octahedral shaped Fe₃O₄ and α-Fe₂O₃ nanoparticles were prepared by simple chemical oxidation method. The prepared magnetic nanoparticles were surface modified with carbon using sugar solution as a carbon source. The crystallinity, structural and morphological studies through XRD, FESEM and TEM analysis confirmed the successful formation of the desired nanostructures. The obtained carbon modified octahedral shaped Fe₃O₄ nanoparticles exhibited a larger saturation magnetization of 87 emu/g. Further, the carbon modified magnetic hybrid nanoparticles were exploited as a negative electrode material for supercapacitor application and observed a high specific capacitance value of 274 F/g for the post annealed samples. The enhanced specific capacitance value is due to the fraction of carbon in hybrid material and it could be enhanced further by increasing the carbon fraction. The cycle stability performance was tested with 5 A/g and showed 83% retention even after 5000 cycles.

https://doi.org/10.1016/j.apsusc.2019.04.177