(378e) Improving Hydrogen Storage Performance of Clathrate Hydrates Formed within Superabsorbent Polymers

Clathrate hydrates offer a promising solution for efficient hydrogen storage due to their environmentally friendly nature and high storage capacity. However, practical application faces challenges from demanding thermodynamic conditions and slow formation kinetics. This study introduces the use of superabsorbent polymers (SAPs) as a dispersion medium for tetrahydrofuran (THF) solutions to accelerate hydrogen enclathration. Two synthetic pathways, solution-borne and hydrate-borne, were explored, along with varying THF solution concentrations within SAPs, and their effects on binary THF-hydrogen hydrates' hydrogen uptake/storage capacity. After a 200-minute enclathration reaction, hydrogen storage capacity was modest for 1.0 mol% THF cases but significant for 5.56 mol% THF cases in the hydrate-borne route, demonstrating its potential as a hydrogen storage material. Spectroscopic analysis revealed a tuning phenomenon in the 1.0 mol% THF hydrate only in the solution-borne route, facilitating hydrogen enclathration in partially vacant large cages of sII hydrates. Surprisingly, the tuning phenomenon was observed in both solution-borne and hydrate-borne pathways for 5.56 mol% THF hydrate. Phase equilibria measurements confirmed less than 5.56 mol% of THF participating in forming binary hydrates. The varying water and THF absorbability of SAPs resulted in non-uniform distribution of THF solution within SAPs, causing the tuning phenomenon. These insights highlight SAPs' potential as rapid hydrogen enclathration media, emphasizing the importance of understanding synthetic pathways and solution absorption properties for optimized hydrogen storage.