Enhanced Supercapacitive and Magnetic Performances of Ho3+ Doped Iron Oxide Nanoparticles Prepared Through a Novel One‐Pot Electro‐Synthesis Method

Abstract

A novel one‐step electro‐chemical synthesis platform is developed for the preparation of Ho3+ doped iron oxide nanoparticles (Ho‐IONPs). In this procedure, Ho‐IONPs are electro‐synthesized from an additive‐free aqueous solution of mixed Fe(NO3)3 · 9H2O, FeCl2 · 4H2O, and HoCl3 · 6H2O with applying dc current density of 10 mA cm−2 for 30 min. The characterization data provided by X‐ray diffraction (XRD), field emission electron microscopy (FE‐SEM) and energy‐dispersive X‐ray (EDX) confirmed that the synthesized Ho‐IONPs have composition of magnetite crystal structure doped with 20 wt.% Ho3+ cations and average particles size of about 10 nm. The electrochemical results obtained galvanostatic charge‐discharge (GCD) tests showed that Ho‐IONPs could provide specific capacitance as high as 222 F g−1 at discharging condition of 0.5 A g−1, and 95.6% capacity retention after 1000 GCD cycling, which confirmed the suitability of the electro‐synthesized Ho‐IONPs for use in supercapacitors. The results of vibrating sample magnetometer measurements confirmed better superparamagnetic behavior of Ho‐IONPs (Mr = 0.14 emu g−1 and HCi = 2.37 G) as compared with pure IONPs (Mr = 0.95 emu g−1 and HCi = 14.62 G) resulting from their lower Mr and HCi values. Based on the obtained results, the developed electro‐synthesis method is introduced as a facile procedure for the preparation of high performance metal ion doped magnetite nanoparticles.