Kinetic and Mechanistic Studies of Intercalation in Lamellar Hosts Using Time-Resolved X-Ray Diffraction

Energy dispersive X-ray diffraction (EDXRD) has been used to perform in-situ kinetic studies on the intercalation of a range of guest molecules in layered lattices. The kinetics of the intercalation of cations {K⁺, PyH⁺ (Py = C₅H₅N), NMe⁺₄} and the long chain ammonium ions C₁₂TMA, C₁₆TMA, C₁₈TMA (C₁₂TMA = dodecyltrimethylammonium, C₁₆TMA = hexadecyltrimethylammonium and C₁₈TMA = octadecyltrimethylammonium) into crystals of MnPS₃ have been determined. These reactions are very fast and in some cases novel transient phases are observed. The rate of cobaltocene, Co(η-C₅H₅)₂, intercalation in layered dichalcogenides ZrS₂, 2H-SnS₂, 2H-SnSe₂, 2H-TaS₂, 2H-NbS₃, 1T-TaS₂ and TiS₂ has also been investigated. Integrated intensities of the Bragg reflections have been used to determine the extent of reaction, (α), versus time for each of these reactions. A number of kinetic models have been considered, including the Avrami-Erofeyev (m = 1.5) deceleratory nuclei-growth model and statistical simulation. The concentration and solvent dependence of the rate of Co(η-C₅H₅)₂ intercalation into 2H-SnS₂ has also been determined. Surprisingly we find that the rate of intercalation is invariant to the initial Co(η-C₅H₅)₂ concentration over a wide concentration range.