Hydrogen transportation properties in carbon nano-scroll investigated by using molecular dynamics simulations

Abstract

Hydrogen, of which the application is limited due to the difficulties in finding the ideal transportation material, has been considered the alternative for petroleum as the main energy source. With its large surface area and other extraordinary physical properties, carbon nano-scroll (CNS) has been the focus of many researchers as the promising candidate for hydrogen storage and transportation. In this work, the transportation characteristics of hydrogen atoms through CNS have been investigated by MD simulations. We found that, by pumping the hydrogen atoms from the reservoir, more hydrogen atoms are likely to attach to the inner layer of CNS instead of leaking into the air. And the average velocity of the hydrogen atoms moving inside the CNS tube is decreasing throughout the simulation. Moreover, the CNS is observed to be slightly tilted and deformed due to the strain energy induced by the interaction between hydrogen and carbon atoms. In addition, effect of the pumping speed on the transportation properties has been studied as well. We conclude that, with greater pumping speed, the hydrogen atoms are more likely to escape into the air. Furthermore, the bigger the diameter of the CNS, the greater number of hydrogen atoms are to be absorbed and leaked as well. Lastly, the effect of the CNS length on the transportation properties has also been studied. We found that, towards the end of the simulations, cases with longer CNS exhibit higher hydrogen leak. And the average velocities of the hydrogen atoms moving in the CNS tube in these cases are also greater.