Co3O4 nanoplates: Synthesis, characterization and study of optical and magnetic properties

The selective synthesis of spinel-type Co3O4 nanostructure with nanoplates morphology was successfully achieved by solid-state thermal decomposition of the [Co-II(NH3)(6)](C2O4)center dot 4H(2)O complex at 350 degrees C without employing any solvent, surfactant and complicated equipment. The product was characterized by thermal analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and magnetic measurements. The TEM images show that the product has a plate-like shape with length of 50-200 nm and thickness of 10-20 nm. FT-IR, XRD, EDX and VSM results suggest the as-prepared Co3O4 nanoplates are pure and single-phase with a weak ferromagnetic behavior. The optical spectrum indicated two direct band gaps at 2.18 and 3.55 eV with a blue shift compared with the bulk samples. The plausible pathway for the formation of Co3O4 nanoplates was also proposed. Under the present reaction conditions, the decomposition of other cobaltammine complexes and CoC2O4 center dot 2H(2)O led to the Co3O4 nanoparticles and nanorods, respectively. (C) 2013 Elsevier B.V. All rights reserved.