LAUSR

Abstract In this research, a novel one-pot fabrication platform was developed for the preparation of Dy 3+ -doped iron oxide nanoparticles (Dy-IONPs). In the procedure, Dy-IONPs are electro-deposited from an additive-free aqueous mixed solution of iron(III) nitrate, iron(II) chloride and dysprosium chloride salts through applying a current density of 10 mA cm –2 for 30 min. The analytical data obtained from X-ray diffraction (XRD), field emission electron microscopy (FE-SEM) and energy-dispersive X-ray (EDX) confirmed the deposited Dy-IONPs to be composed of magnetite nanoparticles (size≈20 nm) containing about 10 wt% of Dy 3+ cations as the doping agent. The electrochemical data obtained through galvanostatic charge-discharge (GCD) tests showed that Dy-IONPs provide specific capacitances values of as high as 202 and 111 F g −1 at the discharge loads of 0.5 and 5 A g −1 , respectively, and reveal capacity retentions of 93.9% and 77.2% after 2000 GCD cycling. These could be held as proof that the electro-synthesized Dy 3+ -doped Fe 3 O 4 NPs are suitable candidates for use in supercapacitors. Furthermore, the results of vibrating sample magnetometer (VSM) measurements indicated better superparamagnetic behavior of the Dy-IONPs ( Mr = 0.34 emu g –1 and H Ci = 6.25 G) as opposed to pure IONPs ( Mr = 0.95 emu g –1 and H Ci = 14.62 G), which originates from their lower Mr and Hci values. Based on the results, the proposed electro-synthesis method offers a facile procedure for the preparation of high- performance metal-ion-doped IONPs.