Molecular-thin bilayer carbon membranes for high-performance CO2 separation
Next-generation carbon capture relies on membrane materials that simultaneously achieve molecular-level thinness, precise nanopore control, and exceptional mechanical robustness, a longstanding trilemma in membrane science. Here, we report graphene–amorphous carbon (GAC) bilayer membranes that overcome this challenge via a graphene-guided polymer conversion approach. Leveraging a super‑spreading effect, we uniformly coat graphene with an ultrasmooth, polymer‑derived carbon layer as thin as 2 nm, yielding outstanding mechanical strength with a Young’s modulus around 26.8 GPa. Meanwhile, controlled pyrolysis of the polymer precursor on graphene generates a carbon network containing high‑precision, narrowly distributed ultramicropores, as confirmed by atomic‑resolution electron microscopy. The resulting GAC membranes exhibit sharp molecular sieving (CO2/N2 > 60, H2/CO2> 70, CO2/CH4 > 70) alongside exceptionally high CO2 permeance up to 5000 GPU, surpassing the state-of-the-art membranes. This combination of normally conflicting properties enables highly efficient carbon capture from flue gas, syngas, and natural gas streams, establishing GAC membranes as a versatile and energy‑efficient platform for sustainable molecular separations.
