Hydrogen Storage in Double Clathrates with tert-Butylamine

The first proof-of-concept of the formation of a double tert-butylamine (t-BuNH2) + hydrogen (H-2) clathrate hydrate has been demonstrated. Binary clathrate hydrates with different molar concentrations of the large guest t-BuNH2 (0.98-9.31 mol%) were synthesized at 13.8 MPa and 250 K, and characterized by powder X-ray diffraction and Raman microscopy. A structural transformation from sVI to sII of t-BuNH2 hydrate was clearly observed under hydrogen pressures. Raman spectroscopic data suggested that the hydrogen molecules occupied the small cages and had similar occupancy to. hydrogen in the double tetrahydrofuran (THF) + H-2 clathrate hydrate. The hydrogen storage capacity in this system was similar to 0.7 H-2 wt% at the molar concentration of t-BuNH2 close to the sII stoichiometry.