Mechanical and adsorption properties of greenhouse gases filled carbon nanotubes

TL;DR

This study uses simulations to explore how greenhouse gases like CO2 and CH4 interact with carbon nanotubes, revealing their potential for gas separation and their mechanical stability under different conditions.

Contribution

It provides new insights into the mechanical and adsorption behaviors of gas-filled carbon nanotubes, highlighting their stability and separation capabilities.

Findings

CO2 strongly interacts with nanotubes, especially in smaller diameters.

Gas presence does not affect nanotube tension response.

Zigzag nanotubes are more mechanically stable with gas fillers.

Abstract

We investigate the mechanical and adsorption properties of single-walled carbon nanotubes (SWCNTs) filled with greenhouse gases through Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) simulations using a recently developed parameterization for the cross-terms of the Lenard-Jones (LJ) potential. Carbon nanotubes interact strongly with CO$_2$ compared to CH$_4$, resulting in a CO$_2$-rich composition inside the nanotubes, with the proportion of CO$_2$ decreasing as the diameter of the nanotubes increases. Contrarily, the smallest nanotubes showed a more even balance between CO$_2$ and CH$_4$ due to gas solidification. The gas does not affect the mechanical response of the nanotubes under tension, but under compression, it presents a complex relationship with the loading direction, nanotube's diameters, chirality, and to a minor extent, the gas composition. Filled zigzag nanotubes showed to be more stable in the presence of fillers, giving the best mechanical performance compared to the filled armchairs. The study confirms carbon nanotubes as effective means of separating CO$_2$ from CH$_4$, presenting good mechanical stability.