Low-pressure experiments on Ar-CH4 gaseous mixtures adsorption over exfoliated graphite: Evidence of kinetic selectivity shift

► We performed experiments in the low pressure regime for binary gas mixture adsorption. ► A short initial stage in which low-binding species coverage builds up was observed. ► We provide first experimental evidence of the already theoretically predicted overshoot. ► Significant for kinetics-based gas separation methods, as opposed to energetic-based.