Millisecond lattice gasification for high-density CO2- and O2-sieving nanopores in single-layer graphene

Etching single-layer graphene to incorporate a high pore density with sub-angstrom precision in molecular differentiation is critical to realize the promising high-flux separation of similar-sized gas molecules, e.g., CO2 from N-2. However, rapid etching kinetics needed to achieve the high pore density is challenging to control for such precision. Here, we report a millisecond carbon gasification chemistry incorporating high density (>10(12) cm(-2)) of functional oxygen clusters that then evolve in CO2-sieving vacancy defects under controlled and predictable gasification conditions. A statistical distribution of nanopore lattice isomers is observed, in good agreement with the theoretical solution to the isomer cataloging problem. The gasification technique is scalable, and a centimeter-scale membrane is demonstrated. Last, molecular cutoff could be adjusted by 0.1 angstrom by in situ expansion of the vacancy defects in an O-2 atmosphere. Large CO2 and O-2 permeances (>10,000 and 1000 GPU, respectively) are demonstrated accompanying attractive CO2/N-2 and O-2/N-2 selectivities.

Automated summary

This study reports a millisecond carbon gasification chemistry that incorporates high density of oxygen clusters, evolving into CO2-sieving vacancy defects under controlled and predictable gasification conditions. A statistical distribution of nanopore lattice isomers is observed, and the technique is scalable.