Hydrogen can play a central role in a fossil-free energy economy, yet its implementation is hindered by the lack of safe, dense, and efficient storage methods. Hybrid H₂ physisorption-hydrate formation, which combines physisorption in porous materials with encapsulation in clathrate hydrates, presents a promising route, but the fundamental synergistic mechanisms remain largely elusive. Here, we perform microsecond-scale molecular dynamics simulations to study the hybrid H₂ storage process in the hydrophobic metal–organic framework ZIF-8 seeded with THF hydrate nanoparticles. The results indicate that ZIF-8 rapidly physisorbs H₂, while effectively excluding H₂O and THF. Our simulations reveal a dynamic, three-step hybrid storage pathway, i.e. , (1) ZIF-8 selectively adsorbs and enriches H₂ within its pores, creating a high local H₂ concentration; (2) The growing binary H₂-THF hydrate crystals selectively capture the H₂; (3) Transfer of H₂ from the ZIF-8 to the hydrate until the hydrogen source transfer reaches a dynamic equilibrium. This hybrid storage method results in a total H₂ storage capacity reaching 1.82 wt%, exceeding the storage capacity of either physisorption or THF-driven hydrate formation alone. These findings provide critical molecular-level insights, showing that coupling hydrophobic ZIF-8 with hydrate promoters is a highly effective strategy for developing next-generation H₂ storage methods.

Knowledge of the microscopic behavior of CO₂ hydrates in oceanic sediments is crucial to evaluate the efficiency and stability of hydrate-based CO₂ sequestration in oceans. Here, systematic molecular dynamics simulations are executed to investigate the growth and dissociation of CO₂ hydrates, and the mechanical instability of CO₂ hydrate-Illite interface in the brine-urea-Illite system. Simulation results show that the CO₂ hydrate growth is jointly affected by the confined space, Illite surface properties, and presence of urea. Specifically, the interfacial H₂O and the ion layer on the Illite surface hinder the growth of CO₂ hydrate crystals toward Illite surfaces. Urea molecules can bind salt ions and increase CO₂ concentrations in the water, thus kinetically promoting CO₂ hydrate growth. The dissociation of the CO₂ hydrate is affected by Illite surface properties and the CO₂ hydrate structure. CO₂ hydrate starts from the regions where hydrate particles are minimally in contact and extends on both sides. The mechanical tension and compression of the CO₂ hydrate-Illite interface exhibit nonlinear characteristics by changing the hydrogen bonds and the CO₂ hydrate structure. The molecular insight into the microscopic behavior of CO₂ hydrates in the brine-urea-Illite system contributes to a broader understanding of hydrate-based CO₂ sequestration.

A microscopic insight into hybrid CH₄ physisorption-hydrate formation in halloysite nanotubes (HNTs) is vital for understanding the solidification storage of natural gas in the HNTs and developing energy storage technology. Herein, large-scale microsecond classical molecular dynamics simulations are conducted to investigate CH₄ storage in the HNTs via the adsorption-hydration hybrid (AHH) method to reveal the effect of gas-water ratio. The simulation results indicate that the HNTs are excellent nanomaterials for CH₄ storage via the adsorption-hydration hybrid method. The CH₄ physisorption and hydrate formation inside and outside of the HNTs are profoundly influenced by the surface properties of the HNTs and the kinetic characteristics of CH₄/H₂O molecules. The outer surfaces of the HNTs exhibit relative hydrophobicity and adsorb CH₄ molecules to form nanobubbles. Moreover, CH₄ molecules adsorbed on the outer surface are tightly trapped between the hydrate solids and the outer surface, inhibiting their kinetic behavior and favoring CH₄ storage via physisorption. The inner surface of the HNTs exhibits extreme hydrophilicity and strongly adsorbs H₂O molecules; thus, CH₄ hydrate can form inside of the HNTs. It is more difficult for CH₄ and H₂O molecules inside of the HNTs to convert into hydrates than for those outside of the HNTs. A moderate gas-water ratio is advantageous for CH₄ physisorption and hydrate formation, whereas excessively high or low gas-water ratios are unfavorable for efficient CH₄ storage. These insights can help to develop an efficient CH₄ solidification storage technology.

Both CH₄ hydrate accumulation and hydrate-based CO₂ sequestration involve hydrate formation in mixed clay sediments. The development of realistic clay models and a nanoscale understanding of hydrate formation in mixed clay sediments are crucial for energy recovery and carbon sequestration. Here, we propose a novel molecular model of pseudo-hexagonal montmorillonite nanoparticles. The stress-strain curves of tension, compression, and shear of pseudo-hexagonal montmorillonite nanoparticles exhibit linear characteristics, with tension, compression, and shear moduli of ∼435, 410, and 137 GPa, respectively. We perform microsecond molecular dynamics simulations to study CH₄ and CH₄/CO₂ hydrate formation in montmorillonite-illite mixed clay sediments with surface defects. The results indicate that hydrate formation in mixed clay sediments is significantly influenced by the presence of clay defects. CH₄ and CH₄/CO₂ mixed hydrates are challenging to form at the junction between the inside and outside clay defects. CH₄ and CH₄/CO₂ mixed hydrates exhibit a preference for forming outside the clay defects rather than inside the clay defects. Some CH₄ and CO₂ molecules from the inside clay defect migrate to the outside clay defect, thereby promoting CH₄ and CH₄/CO₂ mixed hydrate formation outside the clay defects. This molecular insight advances the development of clay particle models and expands an understanding of natural gas hydrate accumulation and hydrate-based CO₂ sequestration.