(515h) Aqueous Hydrogen in Confinement: Structural and Dynamical Properties Estimated from Simulations

As the global focus on harnessing hydrogen energy to decarbonize diverse industrial sectors intensifies, the need for innovative approaches to store large volumes of this gas intermittently becomes more pressing. Large-scale underground hydrogen storage (UHS) might emerge as a viable solution. In this context, we investigate the solubility and diffusivity of hydrogen gas under confinement. Molecular Dynamics (MD) Simulation was employed for this project. The results are discussed in relation to the properties of confined water and compared to those obtained previously from our group for other gases in aqueous confinement, for instance, CO₂ [1], CH₄ [2], and H₂S [3]. In this research, nano-confinement and pore size variations of kaolinite material were proven to influence both hydrogen and water structural and dynamical properties. Particularly, hydrogen solubility was enhanced significantly with unexpected distribution of the gas and water molecules. In addition, the results also revealed interesting diffusivity behavior of aqueous hydrogen. Notably, the study unveiled the mechanism for fascinating observations of structural and dynamical properties of hydrogen gas within hydrated kaolinite pores. In conclusion, this research offers valuable insights and once verified experimentally, it could be attributed to optimizing strategies for large-scale UHS and enhancing the efficiency of hydrogen storage systems.

_{[1] A. Ali, A. Striolo, and D. R. Cole, "CO2 Solubility in Aqueous Electrolyte Solutions Confined in Calcite Nanopores", J. Phys. Chem. C, 2021, 125(22), 12333-12341.}

_{[2] A. Phan, D. R. Cole, and A. Striolo, "Aqueous Methane in Slit-Shaped Silica Nanopores: High Solubility and Traces of Hydrates", J. Phys. Chem. C, 2014, 118(9), 4860-4868.}

_{[3] S. B. Badmos, A. Striolo, and D. R. Cole, "Aqueous Hydrogen Sulfide in Slit-Shaped Silica Nanopores: Confinement Effects on Solubility, Structural, and Dynamical Properties", J. Phys. Chem. C, 2018, 122(26), 14744-14755.}