Facile Synthesis and Characterization of Mn3O4, Co3O4, and NiO

Nanoparticles of three transition metal oxides (Mn3O4, Co3O4, and NiO) were prepared by facile and green method using calcination of mixture of 1 g MCl2 (M = Mn, Co or Ni) and 1 g polyvinyl alcohol (PVA) in weight ratio 1:1 at 600 • C for 3 h.The resulting products were characterized by the Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy.Sharp peaks unambiguously explain all X-ray diffraction patterns which confirms that the transition metal oxide nanoparticles are pure with high degree of crystallinity.However, diffraction peaks in Mn3O4 and Co3O4 patterns are narrower than those in NiO which indicates that the particle size of these oxides is larger than that one of nickel oxide.This result was confirmed by transmission electron microscopy.The average crystallite size determined for Mn3O4 sample is 101 nm, for Co3O4 sample it is 76 nm and for NiO sample it is 49 nm.