Preparation and spectroscopic characterization of ilmenite-type CoTiO 3 nanoparticles

Abstract

The cobalt titanate, CoTiO3 nanoparticles have been prepared by calcinations of precursor obtained from a mixture of TiO2 and Co(OH)2 in aqueous cetyltrimethylammonium bromide (CTAB) solution. The nanoparticles were investigated with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric/differential thermal analysis (TGA/DTA) to determine the crystallite size and the phase composition. The spectroscopic characterizations of these nanoparticles were also done with UV-Vis spectroscopy and FT-Raman spectroscopy. XRD patterns show that CoTiO3 phase was formed at calcinations temperature above 600°C. UV-Vis absorption spectra indicate that the CoTiO3 nanoparticles have significant red shift to the visible region (400-700 nm) with λmax = 500 nm compared to pure TiO2 powder (λmax = 320 nm). The new absorption peaks (absorption at 696, 604, 520, 478, 456, 383, 336, 267, 238, 208 cm-1), which were not appeared in FT-Raman spectra of P-25, also confirm the formation of Ti-O-Co bonds at above 600°C and just not the mixtures of titanium dioxide with cobalt oxides.