Adsorption of n-Alkane Vapours on Graphon

Abstract

Adsorption isotherms on Graphon have been obtained for a scries of n-alkanes from C5 to Ci2- Isosteric heats of adsorption as a function of fractional surface coverage were calculated for the members C6> C7 and C8. Areas per molecule at monolayer coverage indicate that molecules adsorbed in the first layer lie flat on the Graphon surface. The increment per methylene group is in good agreement with a lattice fit theory with hydrogen atoms on one side of the zig-zag carbon chain located in the centres of hexagons of the graphitic basal planes. Heats of adsorption for n-alkanes C7 and above show considerable enhancement just below monolayer coverage. Such enhancements would result from a lattice fit configuration allowing increased adsorbate-adsorbent interaction.