Pore-Width-Dependent Preferential Interaction of sp2 Carbon Atoms in Cyclohexene with Graphitic Slit Pores by GCMC Simulation

The adsorption of cyclohexene with two sp2 and four sp3 carbon atoms in graphitic slit pores was studied by performing grand canonical Monte Carlo simulation. The molecular arrangement of the cyclohexene on the graphitic carbon wall depends on the pore width. The distribution peak of the sp2 carbon is closer to the pore wall than that of the sp3 carbon except for the pore width of 0.7 nm, even though the Lennard-Jones size of the sp2 carbon is larger than that of the sp3 carbon. Thus, the difference in the interactions of the sp2 and sp3 carbon atoms of cyclohexene with the carbon pore walls is clearly observed in this study. The preferential interaction of sp2 carbon gives rise to a slight tilting of the cyclohexene molecule against the graphitic wall. This is suggestive of a proton-proton interaction between the sp2 carbon in the cyclohexene molecule and graphitic carbon.