Graphene quantum dot membranes with tailorable pores for efficient gas separation.

Abstract

Membrane materials and fabrication methods often need to be co-developed to meet the specific permeance and selectivity requirements of different gas separation application, which limits the adaptability of membrane technology. Here we propose a post-regulation strategy-adjusting the pore structures of a standard "primitive" membrane to meet various separation needs-that greatly simplifies membrane preparation and accelerates technological advancement. Graphene quantum dots (GQDs) are introduced as innovative building blocks: a continuous GQD membrane is constructed by tightly stacking GQDs, and then its pore structure is tuned via heat treatment and in-situ cross-linking with small amine molecules. Combining adjustable angstrom-scale pores with preferential CO₂ adsorption, the resulting GQD membranes exhibit widely tunable CO₂/N₂ and CO₂/CH₄ separation performances. The CO₂ permeance and separation factors surpass most reported membranes and can be tuned to exceed industrial targets for CO₂ capture. By varying the heat treatment temperature, the separation scope of the membrane is further extended to challenging gas pairs such as C₃H₆/C₃H₈, demonstrating the high potential of this customizable post-regulation pore structure strategy.