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.