Isosteric heats of adsorption in the Henry’s law region for carbon single wall cylindrical nanopores and spherical nanocavities

The isosteric heat of adsorption in the Henry’s law region is calculated as a function of the pore width for carbon single wall cylindrical nanopores and spherical nanocavities. The maximum isosteric heat of adsorption is obtained for six gas molecules: argon, methane, carbon dioxide, hydrogen, helium, and nitrogen. In addition, the results for cylindrical carbon nanopores are compared with adsorption data on single-wall carbon nanotubes from the literature. We find the pore width where the isosteric heat of adsorption is a maximum for both geometries. The effect of solid–fluid parameters on the pore diameter for the maximum isosteric heat of adsorption is determined for any system described by a Lennard–Jones potential. Constant relationships between the pore diameters for the maximum isosteric heat of adsorption and the specific solid–fluid parameters are found for cylindrical nanopores, spherical nanocavities, and parallel-wall slit-shaped pores. Surface mean curvature has a significant influence on the isosteric heat of adsorption.