Speaker
Description
Hydrogen transport and storage in water-filled porous media play a critical role in emerging energy technologies, including subsurface hydrogen storage, membrane-based separation, and green housing applications involving hydrogen-enabled energy systems. At the pore scale, accurate prediction of hydrogen solubility and partitioning between aqueous and gaseous phases remains challenging due to the weak, nonpolar nature of hydrogen–water interactions and their sensitivity to molecular force-field descriptions.
In this work, we present a molecular simulation framework to compute the excess chemical potential and Henry’s law constant of molecular hydrogen in liquid water using alchemical free-energy methods. Classical molecular dynamics simulations are performed with explicit rigid water models and physically motivated representations of hydrogen, ranging from Lennard–Jones pseudo-atoms to multi-site quadrupolar models. The solvation free energy is computed via single-replica alchemical transformations using soft-core potentials, combined with free energy perturbation and Bennett acceptance ratio (BAR/MBAR) analysis to ensure statistical robustness.
The methodology explicitly accounts for standard-state corrections required to connect molecular-scale solvation free energies to experimentally reported Henry’s constants, enabling direct comparison with macroscopic thermodynamic data. Preliminary calculations demonstrate stable free-energy convergence across alchemical coupling parameters and highlight the sensitivity of hydrogen solubility predictions to the chosen molecular representation. In particular, inclusion of quadrupolar electrostatics is expected to significantly improve agreement with experimental solubility trends.
Beyond bulk water, the developed framework is directly extensible to confined and heterogeneous aqueous environments representative of porous materials. As such, the results provide essential molecular-level input parameters for continuum-scale models of hydrogen transport in water-saturated porous media, bridging microscopic thermodynamics with macroscopic flow and diffusion descriptions.
Ongoing simulations focus on systematic force-field validation against experimental Henry’s constants and on quantifying the impact of confinement and interfacial effects relevant to porous geomaterials and energy-efficient housing systems. This work contributes a rigorous, transferable computational approach for hydrogen–water thermodynamics, supporting multiscale modeling efforts in energy and porous media research.
| Country | United States |
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