Structure and dynamics of graphite intercalation compounds. Part 2.—Kinetics of formation of C8KD⅔ and C8KH⅔

Abstract

The kinetics of the intercalation of hydrogen and deuterium into C₈K have been studied by neutron powder diffraction. There appear to be two different mechanisms for the reaction of hydrogen or deuterium with C₈K depending upon the temperature. Below ca. 370 K the activation energy derived from the Arrhenius plots is ca. 50 kJ mol^–1 and the reaction order is < 1. In this range the ratio of the rates for hydrogen and deuterium is large. At high temperatures the activation energy was not measurable and the order of the reaction is rather higher, possibly 2. In this temperature range also the isotope effect has decreased. A mechanism involving dissociation and diffusion is invoked to explain these results.