Ice-Inclusion Compounds for Energy Gas Storage

Gas hydrates are types of crystalline-inclusion compounds composed by a ‘host’ framework and ‘guest’ molecules. In general, ‘host’ water molecules constitute the hydrogen-bonded host framework, and ‘guest’ molecules, such as methane, ethane, propane, hydrogen, or carbon dioxide, can be encapsulated in the framework structures. Huge amount of gases can be selectively captured in the hydrate structures, and thus; gas hydrates have been received much attention in the energy and environmental fields for gas storage and separation. Here, we introduced the hydrate-forming agents, including cyclic alcohol and amine molecules, for energy gas storage. The guest inclusion behaviors of binary clathrate hydrates were examined by spectroscopic tools, ¹³C solid-state nuclear magnetic resonance (NMR) spectroscopy and powder X-ray diffraction (PXRD) analysis. The storage capacity of methane gas in the binary clathrate hydrates was also examined. The findings, regarding the inclusion behavior of cyclic molecules in hydrate cages, the storage capacity of methane in hydrate structure, and the thermodynamic stability of the binary clathrate hydrates, may provide fundamental information on the complex nature of host–guest inclusion chemistry and lend useful insights with respect to potential gas hydrates applications for gas storage.