Mechanisms of Hydrogen Transport in Flexible-Wall Narrow Carbon Nanotubes

Abstract EN

Understanding the interaction between hydrogen and carbon nanotubes is crucial to enhancing the performance of hydrogen storage and nanofluidic carbon-adsorbent systems.

Accordingly, this study performs a series of molecular dynamics simulations to investigate the transport properties of hydrogen molecules confined within a flexible narrow carbon nanotube.

The tube’s diameter is 10.8 Å at temperatures in the range of 100~800 K.

The particle loadings inside carbon nanotubes are ranging from 0.01∼1 No/Å.

The results show that the hydrogen molecules exhibit three distinct diffusion regimes, namely, single-file, Fickian, and ballistic, depending on the value of the Knudsen number.

In addition, it is shown that with the Knudsen number of less than 1, the tube-wall long wavelength acoustic phonons induced Rayleigh traveling wave prompts a longitudinal wave slip and compression-expansion of the hydrogen molecule crowds within the CNT, which leads to a significant increase in the mean square displacement of the molecules.