Helical confinement effects on hydrogen storage in double-walled carbon nanotubes

Molecular configurations are some of the important factors that strongly affect the hydrogen adsorption in carbon nanotubes (CNTs). A Quantum Molecular dynamics simulations are performed to study the adsorption isotherm of torsional double-walled carbon nanotubes (DWCNTs) filled with hydrogen molecules. The considered key factors that affect the hydrogen storage responses of the DWCNTs are the adsorption energy and the surface tension effect. Our simulated results show that 2-sided effect is observed and kinetic diameter of H2 molecules is shortened approximately 4.11% under helical confinement. The results further reveal that the amounts of hydrogen storage wt% are computed at 77 K and found to be 1.77 wt% and 3.92 wt% for pristine and twisted-DWCNTs, respectively. Finally, it is shown that the adsorption heat, which reflects surface property, is twisted dependent.