We investigated the storage capacity of methane on the pristine and doped graphene sheets using hybrid molecular dynamics - grand canonical Monte Carlo simulation method. Methane adsorption on two parallel graphene sheets with various distances was estimated at various pressures. According to the isotherm curves, the maximum amount of adsorbed methane was observed for graphene sheets with a distance layer of 1.2 nm. This optimum structure was further doped separately with lithium, nitrogen and boron atoms in various atomic percentages to examine methane storage contents. Results showed that lithium and nitrogen-doped graphene sheets could enhance the methane storage capacity of graphene sheets whereas boron did not have any significant effect on the methane uptake. The minimum content of dopant atoms for lithium and nitrogen was estimated as 1/12 (lithium atoms/carbon atoms) and 18.5 atomic percentage, respectively, to meet new DOE’s target for methane uptake.

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