Synthesis and characterization of Co3O4 nanoplates by simple thermolysis of the [Co(NH3)6]2(C2O4)3•4H2O complex

Nanoplates of Co3O4 were selectively prepared through solid-state thermolysis of the [Co( NH3)(6)](2)(C2O4)(3)center dot 4H(2)O complex at 350 degrees C without the need for an expensive and toxic solvent/surfactant or complicated equipment. The product was characterized by thermal analysis (TGA/DTG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, UV-Vis 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 was formed mainly from square-like Co3O4 nanoplates with a length of 50 similar to 200 nm and thickness of 10-20 nm. The FT-IR, XRD, Raman, EDS and VSM results confirm that the as-prepared CO3O4 nanoplates are pure and single-phase with a weak ferromagnetic behavior that could be attributed to uncompensated surface spins and/or finite-size effects. The optical spectrum indicated two direct band gaps at 2.15 and 3.50 eV with a blue shift compared with the bulk samples. A plausible pathway for the formation of Co3O4 nanoplates from the [Co( NH3)(6)](2)(C2O4)(3)center dot 4H(2)O complex was also proposed. (C) 2013 Elsevier Ltd. All rights reserved.