Band gap and pseudocapacitance of Gd₂O₃ doped with Ni_0.5Zn_0.5Fe₂O₄

Abstract

Herein, we present a detailed study on the structural, optical, and electrochemical responses of Gd2O3 doped with nickel zinc ferrite nanoparticles. Doping of Ni0.5Zn0.5Fe2O4 nanoparticles to Gd2O3 powder was done through thermal decomposition at 1000 ֯C. The average grain size of the mixture was determined to be approximately 95 nm, and phases of cubic Gd2O3, GdO, and orthorhombic prisms of GdFeO3 were identified. The focused ion beam energy dispersive X-ray spectrum (FIB-EDX) mapping results clearly show the morphology of the particles with Gd and Fe as the dominant elements. The structural data were compared with the spectroscopic measurements confirming the formation of multiple phases of oxides and ferrites. The optical band gap is determined to be at 1.8 eV by diffuse reflectance spectroscopy, which is significantly redshifted compared to the band gap of Gd2O3 and is close to that of nitride compounds of rare earth metals. The measured specific capacitance was almost 7 Fg-1 at a current density of 1 Ag-1, showing a small drop of 27% when the current density is increased to 10 Ag-1. Cyclic voltammetry (CV) plots of the ferrite doped Gd2O3 electrode at a scan rate of 5 to 100 mV/s indicate the pseudocapacitive nature of the material.