Synthesis and Application of Inverse Spinel NiFe2O4 Produced by EDTA-citrate Method: Structural, Vibrational, Magnetic, and Electrochemical Properties

In this paper we studied the production of single-phase NiFe2O4 powders synthesized by the complexation method combining EDTA-citrate. The structural, optical, magnetic, and electrochemical properties of were studied as a function of the synthesis pH. Powders obtained with pH 9 showed larger crystallite sizes (73 nm) in comparison to those produced with pH 3 (21 nm). The band gap energy was found to be inversely proportional to the crystal size (1.85 and 2.0 eV for powders with crystallites of 73 nm and 21 nm, respectively). The synthesized materials presented an inverse spinel crystalline structure. The samples obtained at higher pH conditions were found to be fully magnetic saturated with a saturation magnetization of 50.5 emu g-1, while that synthesized at pH 3 is unsaturated with a maximum measured magnetization of 48.4 emu g-1. Cyclic voltammetry and charge-discharge curves indicate a battery-type behavior, with an better performance for the material obtained at pH 9 (65 C g-1 at a specific current of 3 A g-1). The remarkable performance of the associated with its by microstructural characteristics (particle size, particle agglomeration and porosity). This work offers an alternative synthesis route for obtaining spinel ferrites for magnetic and electrochemical applications.