Characterization of cobalt oxide supported on titania prepared by microwave plasma enhanced chemical vapor deposition

The microwave plasma enhanced chemical vapor deposition (MPECVD) was applied for the preparation of cobalt oxide supported on titania, CoOx/TiO2, starting from Cobalt(III) acetylacetonate, Co(acac)3, (precursor) and TiO2 (support). The obtained CoOx/TiO2 materials were characterized by inductive coupled plasma–optical emissions spectroscopy (ICP-OES), thermogravimetric analysis–difference thermo analysis (TG/DTA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) investigations. Evidence is given that Co(acac)3 is evaporated and adsorbed on carrier surface in a first step and afterwards decomposed during the microwave-plasma treatment in oxygen atmosphere. As a function of the plasma treatment time and the cobalt content, cobalt oxide species with particle sizes between 2 and 10 nm were deposited on the support. As stated, the MPECVD method may allow, on the one hand, to prepare the CoOx/TiO2 materials with controlled particle size of cobalt oxide and, on the other hand, to avoid the use of salt solvents. This makes the method favorable in comparison with the preparation by impregnation.