Stable low-pressure hydrogen clusters stored in a binary clathrate hydrate.

Area of Science:

• Materials Science
• Chemical Engineering
• Physical Chemistry

Background:

• Hydrogen (H2) clathrate hydrates are a potential medium for gas storage.
• Forming pure H2 clathrates typically requires high pressures, limiting practical applications.
• Stabilizing clathrate structures with guest molecules is a known strategy to modify their properties.

Purpose of the Study:

• To investigate the stabilization of hydrogen clathrate hydrates using a binary system.
• To determine the feasibility of storing hydrogen at reduced pressures.
• To characterize the structure and stability of H2-occupied clathrate cages.

Main Methods:

• Thermodynamic measurements
• X-ray diffraction analysis
• Raman spectroscopy
• Nuclear magnetic resonance (NMR) spectroscopy

Main Results:

• Clusters of H2 molecules were successfully stabilized within small cages of an sII clathrate hydrate.
• Tetrahydrofuran (THF) molecules singly occupied the large cages, acting as a stabilizing co-guest.
• The binary clathrate system allowed H2 storage at significantly lower pressures (5 MPa at 279.6 K) compared to pure H2 hydrate (300 MPa at 280 K).

Conclusions:

• Binary clathrate hydrates offer a promising pathway for low-pressure hydrogen storage.
• The co-occupation of cages by H2 and THF effectively stabilizes the clathrate structure.
• This finding has implications for developing efficient and safe hydrogen storage technologies.