Classification of supercritical gas adsorption isotherms based on fluid–fluid interaction

Based on an increase in fluid–fluid interaction, supercritical gas adsorption isotherms can be classified into three types, Henry-type isotherms, virial isotherms, and cooperative isotherms. The isotherms of the three types differ in terms of the compression factor and the adsorbed layer density. The goodness of this classification is supported by calculations based on the density functional theory. This classification is used for hydrogen adsorption isotherms on a single-wall carbon nanohorn obtained at different temperatures.