Structural, magnetic, electrical and electrochemical properties of NiFe2O4 synthesized by the molten salt technique

Submicron-sized NiFe2O4 particles were synthesized by the molten salt method at 900 °C using binary melts of a NaCl and KCl mixture that acts as a flux. The X-ray diffraction pattern confirmed the single phase, high crystalline and cubic structure of NiFe2O4 with a Fd3m space group. The FT-IR spectra reveal the stretching vibration of octahedral complexes of Fe3+–O2− through the observed band around 552.3 cm−1. The SEM and TEM image had indicated the formation of submicron-sized NiFe2O4 particles. The ferrimagnetic behavior and high saturation magnetization of 44 emu g−1 was elucidated by VSM. The maximum electrical conductivity of 1.42 × 10−4 S cm−1 was observed at 873 K. The NiFe2O4 showed a pseudocapacitive property in 1 M of a LiClO4 electrolyte and exhibited a specific capacitance of 18.5 F g−1 at 10 mV s−1. The hydrogen evolution reaction was also studied for NiFe2O4 in 1 M of a H2SO4 solution.

► The article describes the comprehensive study of molten salt synthesised NiFe2O4. ► The optimized NiFe2O4 were further studied for their application as electrodes in redox supercapacitors and hydrogen evolving reaction (HER) using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques, respectively. ► The electrochemical characterization of NiFe2O4 showed pseudocapacitive property and exhibited specific capacitance of 18.5 F g−1. ► It also confirmed through LSV, the prepared NiFe2O4 has good electrocatalytic behavior compared with its individual constituents like NiO and Fe2O3 as well as the NiFe2O4 prepared by solid state reaction.