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Widespread use of methane-powered vehicles likely requires the development of efficient on-board methane storage systems. A novel concept for methane storage is the nanoporous microtank, which is based on a millimeter-sized nanoporous pellet (the core) surrounded by an ultrathin membrane (the shell). Mixture adsorption simulations in idealized pores indicate that by combining a pellet that features large, hydrophobic pores with a membrane featuring small, hydrophilic pores, it would be possible to trap a large amount of “pressurized” methane in the pellet while keeping the external pressure low. The methane would be trapped by sealing the surrounding membrane with the adsorption of a hydrophilic compound such as methanol. Additional simulations in over 2000 hypothesized metal–organic frameworks (MOFs) indicate that the above design concept could be exploited using real nanoporous materials. Structure–property relationships derived from these simulations indicate that MOFs suitable for the core (storing over 250 cc(STP) CH4 per cc) should have a pore size in the 12–14 Å range and linkers without appreciably hydrophilic moieties. On the other hand, MOFs suitable for the shell should have a pore size less than 9 Å and linkers with hydrophilic functional groups such as –CN, –NO 2 , –OH and –NH 2 . Simulation snapshots suggest that the hydrogen bonding between these groups and hydrophilic moieties of methanol would be critical for the sealing function.
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This content will become publicly available on August 26, 2026
Electrosorption-Induced Deformation of Nanoporous Carbons: Solvation Pressure from Molecular Dynamics and Continuum Theory
Nanoporous carbons play an important role in different electrochemical applications such as being utilized as electrodes in supercapacitors. Application of electric potential to a porous electrode in electrolyte solution stimulates adsorption or desorption of ions on the electrode surface. Electrosorption causes appearance of solvation pressure in the pores and results in electrode deformation. In this work, using molecular dynamics simulations and the continuum theory based on the modified Poisson-Boltzmann equation, we studied the structure of the electrical double layer in slit graphitic micropores filled with a NaCl aqueous solution, and solvation pressure in these pores. We focused on the behavior of the solvation pressure as a function of pore width and surface charge density. Within molecular dynamics simulations, two different water models were used -- an explicit model based on SPC/E water molecules and an implicit model, i.e., structureless background with fixed dielectric permittivity. The latter allows us to relate molecular dynamics simulations to the continuum theory. Simulations with explicit water show a qualitatively different behavior of the solvation pressure in the 1 and 2 nm pores as a function of the surface charge density. We demonstrated that the value of the solvation pressure is defined by a delicate balance between Van der Waals and electrostatic contributions. We demonstrated that the theory predicts the dependence of the solvation pressure on the pore width, which matches the results of simulations using the implicit water model. Finally, we adapted the continuum theory, developed for adsorption-induced deformation to estimate the deformation of a carbon electrode due to electrosorption. Our results can be used in the further development of nanoporous actuators working based on electrosorption-induced deformation.
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- Award ID(s):
- 2234028
- PAR ID:
- 10631127
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- The Journal of Physical Chemistry C
- ISSN:
- 1932-7447
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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