Gated CO₂ permeation across dynamic graphene pores

Oxidation of graphene has been successfully used to incorporate semiquinone (C = O)-functionalized Å-scale pores, yielding attractive carbon capture performance. However, the true potential of such pores has remained unclear due to a lack of dedicated mechanistic studies. Herein, using molecular dynamics (MD) simulations, we show that C = O displays a strong molecular-interaction-dependent dynamic motion, leading to a distribution in the pore limiting diameter (PLD), comparable to the size differences between CO₂, O₂, and N₂. Dynamic open and closed pore states are observed in small pores, making impermeable pores CO₂-permeable. The strong molecular interaction eliminates effusive transport, resulting in selective gating of CO₂ from O₂ and N₂, even from large PLD pores which are expected to be nonselective. Finally, the transition-state-theory (TST) calculations validated against MD simulations reveal the immense potential of porous graphene for carbon capture beyond the state-of-the-art membranes. These insights will inspire improved graphene membrane design, pushing the carbon capture frontier.