Spinel-Type Cobalt Oxide (Co3O4) Nanoparticles from the mer-Co(NH3)3(NO2)3 Complex: Preparation, Characterization, and Study of Optical and Magnetic Properties

In this paper, the mer-Co(NH3)3(NO2)3 complex was used as a new precursor for synthesizing spinel-type cobalt oxide nanoparticles (Co3O4NPs).Thermal decomposition of the complex at low temperature (175 °C) resulted in the Co3O4NPs without using expensive and toxic solvents or complicated equipment. XRD, FT-IR, SEM, EDX, and TEM were employed to characterize the product, and its optical and magnetic properties were studied by UV-visible spectroscopy and a VSM, respectively. FT-IR, XRD and EDS analyses confirmed the formation of single-phase Co3O4 with cubic structure. The lattice constant calculated from XRD peaks is 8.0650 Å. SEM and TEM images showed that Co3O4NPs have a sphere-like morphology with an average size of 19 nm. Optical spectrum of Co3O4NPs revealed the presence of two band gaps at 2.20 and 3.45 eV values, which in turn confirmed the semiconducting properties. The magnetic measurement of Co3O4NPs showed a weak ferromagnetic order at room temperature.