(726a) High Flux CO2-Selective Single-Layer Graphene Membranes: Synthesis and Scale-up

Nanoporous single-layer graphene (N-SLG), prepared by incorporating subnanometer vacancy defects in the graphene lattice, is highly promising for high flux gas separation because the resistance to diffuse is controlled by a single transition state at the nanopore [1–3]. Molecular sieving resolution (MSR), defined as the difference in the kinetic diameters of molecules to be separated, of 0.3-0.5 Å is needed for CO₂/N₂ and CO₂/CH₄ separation, respectively [4-5].

In this presentation, I will share recent developments in our laboratory on advances on N-SLG membranes including their scale-up to practical dimensions [6-8]. Strategies including controlled etching of graphene lattice, functionalization of graphene lattice as well as hybrid graphene-polymer membranes will be discussed. Specifically, I will discuss a novel etching chemistry, allowing controlled nucleation and expansion of vacancy defects, and yielding MSR of 0.2 Å. We show that molecular cutoff can be adjusted by 0.1 Å by a slow expansion of nanopores, making O₂/N₂ separation possible from atom-thick membranes. Large CO₂ permeances (above 10000 GPU) combined with attractive CO₂/N₂ separation factor (above 20), makes N-SLG membranes highly promising for postcombustion carbon capture. We show that molecular sieving (selectivities > 20) can be obtained from large graphene coupons reaching 1 cm² in size.

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