Improvement of methane storage in nitrogen, boron and lithium doped pillared graphene: A hybrid molecular simulation

Abstract

The aim of this study is to investigate the storage capacity of methane on the doped pillared graphene using molecular simulation. To this end, a pillared graphene containing two parallel graphene sheets with two vertical carbon nanotubes as holders was selected. This carbon structure was doped using nitrogen, boron and lithium atoms to enhance the gas storage capacity. A hybrid molecular simulation - a combination of molecular dynamics and grand canonical Monte Carlo simulation - was applied to simulate the storage capacity of adsorbent. The results showed that in all systems, doping could enhance the storage capacity of pillared graphene in comparison to pure structure. This improvement was more significant for lithium doped structures while the enhancement of methane storage capacity was estimated 28% higher than that of pristine pillared graphene. In all systems, the storage capacity improvement could be reinforced by increasing the doping percentage of dopant atoms, but this difference was more noticeable for the lithium doped structure. Furthermore, lithium doped pillared graphenes at all levels of dopant and nitrogen doped structures with high doping values (equal or greater than18.5%) were shown to meet the recent target set by U.S. Department of Energy for methane storage capacity.