Abstract
Purely trigonal ilmenite type powder; CoTiO3 was successfully synthesized through the thermal decomposition of CoC2O4 center dot 2H(2)O-TiO2 precursor. The decomposition course was followed using differential thermal analysis-thermogravimetry measurements and the intermediate decomposition products as well as the titanate product were characterized using X-ray diffraction, Fourier transform infrared, transmission electron microscopy techniques. Thermal analysis study indicated that, the intermediate decomposition product; Co3O4 decomposed endothermically into CoO at 963 degrees C with instantaneous formation of CoTiO3. X-ray diffraction of the powder calcined at 950 degrees C showed characteristic lines for Co2TiO4 besides secondary phase of rutile-TiO2, which are disappeared by rising the calcination temperature to 1000 degrees C. Transmission electron microscopy image of CoTiO3 powder exhibit weak agglomerated particles with heterogeneous morphology in both shape and dimensions. Type II adsorption isotherm estimated using Brunauer-Emmett-Teller procedure indicated a very high specific surface area of 29.7 m(2) g(-1). Electrical properties of CoTiO3 measured as a function of temperature and frequency showed a semiconducting behavior at high temperatures with conduction activation energy of 0.73 eV. Kinetic analysis of the non-isothermal thermogravimetry curves, using different computational methods, illustrated that the random nucleation and growth mechanisms are the predominant one. (C) 2012 Elsevier Inc. All rights reserved.