Kinetic study of the intercalation of cobaltocene by layered metal dichalcogenides with time-resolved in situ X-ray powder diffraction

Energy-dispersive X-ray diffraction (EDXRD) has been used to perform in situ kinetic studies on the intercalation of cobaltocene, Co(eta-C5H5)(2), into the layered dichalcogenides ZrS2, 2H-SnS2, 2H-SnSe2, 2H-TaS2, 2H-NbS2, 1T-TaS2, and TiS2. Integrated intensities of the Bragg reflections have been used tp determine the extent of reaction (alpha) versus time for each of these reactions. The half-lives (t(1/2)) for reaction of an excess of cobaltocene with ZrS2, 2H-SnS2, 2H-SnSe2, 2H-TaS2, 2H-NbSe2, and TiS2 at 120 degrees C in dimethoxyethane were found to be <5, 31, 410, 16000, 2960, and >60000 s, respectively. A number of kinetic models have been considered, including the Avrami-Erofeyev (m = 1.5) deceleratory nuclei-growth model and statistical simulation. The activation energy for the intercalation of Co(eta-C5H5)(2) in 2H-SnS2 has been determined to be 41 kJ mol(-1). The concentration and solvent dependence of the rate of Co(eta-C5H5)(2) intercalation into 2H-SnS2 has also been determined. Surprisingly we find that the rate of intercalation is invariant to the initial Co(eta-C5H5)(2) concentration over the whole concentration range studied.