Molecular modelling of ionic liquids in the ordered mesoporous carbon CMK-5

Authors

Xiaoxia He, Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Joshua Monk, Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Ramesh Singh, Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Francisco R. Hung, Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LAFollow

Document Type

Article

Date of this Version

2015

Citation

Molecular Simulation, 2015

Comments

U.S. Government Work

Abstract

We performed classical molecular dynamics simulations of the ionic liquids (ILs) [dmim⁺][Cl⁻] and [emim⁺] [NTf₂ ⁻], confined in a model CMK-5 material, which consists of amorphous carbon nanopipes (ACNPs) arranged in a hexagonal array. We compare our findings against the behaviour of the same ILs inside an isolated ACNP (i.e. no IL adsorbed on the outer surface of the ACNP) and inside a model CMK-3 material (which is similar to CMK-5, but is formed by amorphous carbon nanorods). Our results indicate that the presence of IL adsorbed in the outer surface of an uncharged ACNP in CMK-5 affects the dynamics and the density of an IL adsorbed inside the ACNP and vice versa. ILs adsorbed outside the nanopipes in CMK-5 (i.e. with IL also adsorbed inside the nanopipes) have faster dynamics and remain closer to the carbon surfaces when compared to the same ILs adsorbed on CMK-3 materials. The trends are IL-specific: [dmim⁺][Cl⁻] has slower dynamics when inside an isolated ACNP than when inside the ACNPs in CMK-5, but in contrast, [emim⁺][NTf₂ ⁻] moves faster when it is inside an isolated ACNP than when it is inside the ACNPs in CMK-5 (i.e. with IL adsorbed outside the nanopipes).