Spectroscopic identification, thermodynamic stability and molecular composition of hydrogen and 1,4-dioxane binary clathrate hydrate

Abstract

We present the spectroscopic identification of the binary hydrogen and 1,4-dioxane clathrate hydrates in which H, molecules are encapsulated in small cages of the structure II hydrate framework. X-ray diffraction, solid-state NMR and Raman spectroscopy were used to confirm the mixed hydrate structure and more importantly the occupancy pattern of hydrogen in clathrate cages. The corresponding pressure-temperature behavior and direct gas release measurements were also determined to support the spectroscopic results. The direct volumetric measurements revealed that the favorable confinement of hydrogen molecules over 0.4 wt% could be obtained by the compositional tuning of the binary products. (c) 2007 Elsevier Ltd. All rights reserved.