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 i n situ kinetic studies on the intercalation of cobaltocene, Co(eta-C5H 5)(2), into the layered dichalcogenides ZrS2, 2H-SnS2, 2H-SnSe2, 2H-Ta S2, 2H-NbS2, 1T-TaS2, and TiS2. Integrated intensities of the Bragg re flections have been used tp determine the extent of reaction (alpha) v ersus time for each of these reactions. The half-lives (t(1/2)) for re action of an excess of cobaltocene with ZrS2, 2H-SnS2, 2H-SnSe2, 2H-Ta S2, 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 o f 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-S nS2 has been determined to be 41 kJ mol(-1). The concentration and sol vent dependence of the rate of Co(eta-C5H5)(2) intercalation into 2H-S nS2 has also been determined. Surprisingly we find that the rate of in tercalation is invariant to the initial Co(eta-C5H5)(2) concentration over the whole concentration range studied.