The interaction between atomic-scale pores and particles.

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• Angstrom-sized pores in 2D materials are crucial for gas separation.
• Understanding pore-particle interactions is key to optimizing gas permeation.
• Existing models for gas translocation through nanopores have limitations.

Purpose of the Study:

• To investigate pore-particle interactions in angstrom-sized pores (3-10 Å).
• To calculate the translocation energy barrier (TEB) for various gases.
• To determine the dominant gas permeation mechanisms in graphene-based nanopores.

Main Methods:

• First-principles calculations were employed.
• Calculated TEB (Δ) and surface diffusion energy barrier (Δ') for He, Ne, Ar, Xe, H₂, N₂, CO₂, and CH₄.
• Investigated critical incident angle for gas permeation.

Main Results:

• The critical incident angle was found to be 40°, differing from classical predictions (19-37°).
• For small kinetic diameter gases (He, Ne, H₂), direct flow is dominant (Δ ≈ 0, Δ' > 30 meV).
• For larger kinetic diameter gases (Ar, Kr, N₂, CH₄, CO₂), both direct flow and surface diffusion are possible (Δ and Δ' ≠ 0).

Conclusions:

• Gas permeation mechanisms depend on particle size and pore characteristics.
• First-principles calculations provide accurate insights into gas-nanopore interactions.
• Findings advance gas permeation theory and inform the design of gas separation devices.