Isoxazole-Stabilized Clathrate Hydrate for Hydrogen Storage

Safe and efficient hydrogen (H₂) storage remains a key challenge for a carbon-neutral energy future. Clathrate hydrates, ice-like lattices of hydrogen-bonded water, provide a sustainable platform for solid-state H₂ storage under moderate conditions; however, the molecular interactions governing their stability remain poorly understood. Using powder X-ray diffraction and Raman spectroscopy, we demonstrate the first H₂-isoxazole (ISXZ) hydrate and identify a C4-H···O host-guest linkage that stabilizes the structure II lattice. Comparative studies on pure ISXZ and N₂-ISXZ hydrates reveal that even when small cages are vacant or occupied by bulkier N₂, ISXZ maintains lattice stability through this interaction. These findings establish ISXZ as a prototype heteroaromatic promoter and highlight C-H···O bonding as a general motif for designing next-generation gas-storage materials.