Exploring the magnetic and supercapacitor characteristics of praseodymium-doped CoFe₂O₄ magnetic nanoparticles

Pure and Praseodymium (Pr)-doped CoFe₂O₄ magnetic nanoparticles (MNPs) were prepared by chemical oxidation method with optimized experimental parameters. The structural change with increasing doping concentration of Pr was observed from the X-ray diffraction analysis. The spherical morphology of the MNPs was confirmed from field emission scanning electron microscopy and transmission electron microscopy. Magnetic properties of the pure and Pr-doped CoFe₂O₄ are analyzed by vibrating sample magnetometer and thermomagnetic analysis measurements. The maximum saturation magnetization of 77 emu/g was observed for pure CoFe₂O₄ MNPs and decreasing with increasing Pr doping concentration. The curie temperature of CoFe₂O₄ MNPs is observed around 520 °C from TMA measurements. The increase in the current from the cyclic voltammetry results with increasing doping fraction of Pr is observed. The Galvanostatic charge/discharge results revealed that the higher specific capacitance of 121 F/g was achieved for the electrode prepared with 5% of Pr-doped CoFe₂O₄ MNPs. The cyclic stability test suggested that the 5% of Pr-doped CoFe₂O₄ MNPs electrode can show more than 97% of capacity retention even up to 5000 cycles. The observed electrochemical characteristics of the pure and Pr-doped CoFe₂O₄ MNPs suggested that the doping on CoFe₂O₄ MNPs could be adopted to tune the capacitance of the electrode for supercapacitor applications.