Atomic-level mechanisms of methane absorption in silica-based porous materials with non-uniform faults: Enhancing adsorption via surface faults

MY Yang and B Yang and XJ Meng and Q Sheng and L Guo and C Bi and M Du, APPLIED SURFACE SCIENCE, 698, 163069 (2025).

DOI: 10.1016/j.apsusc.2025.163069

Natural gas is a promising clean energy source, but its storage and transport remain challenging. This work demonstrates that a novel silica-based porous structure with non-uniform faults can significantly enhance methane absorption, as revealed through large-time molecular dynamics (MD) simulations of 1500 ns. Silica nanoparticles with random faults were constructed under methane conditions (5 atm), and a validated method was developed to identify absorbed methane molecules, showing good agreement with experimental data. Our findings reveal that optimizing fault density results in a 111 % increase in methane absorption compared to faultfree structures. Absorbed methane molecules form three layers: an absorption layer, a Knudsen layer, and a bulk layer. Faults enhance solid-gas interactions in the absorption layer and gas-gas interactions in the Knudsen layer. However, increasing temperature significantly reduces methane absorption, for which we propose a temperatureabsorption relationship. These insights provide a foundation for designing nanostructures optimized for methane storage and selective absorption applications.

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