Mechanism of thermal decomposition of cobalt acetate tetrahydrate

The thermal decomposition of cobalt acetate tetrahydrate (Co(CH3COO)2 · 4H2O) has been studied via thermogravimetric (TG) analysis, in situ X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results of TG and XRD showed that the parent salt melted and then the dissolved crystalline water was vaporized in two steps. The dehydration process was followed by a major step concerning the decomposition of the acetate group, leading to basic acetate as an intermediate, which then produced CoO and Co in N2 and H2 atmosphere, respectively. Three decomposition intermediates Co(CH3COO)2 · 0.5H2O, Co(CH3COO)2, and Co(OH)(CH3COO) were presumed. In situ XRD experiments revealed that the intermediate basic acetate was poorly crystallized or even amorphous. Evolved gases analysis indicated that the volatile products of acetate decomposition were water vapor, acetic acid, ethylenone, acetone, and CO2. A detailed thermal decomposition mechanism of Co(CH3COO)2 · 4H2O was discussed.