Etching gas-sieving nanopores in single-layer graphene with an angstrom precision for high-performance gas mixture separation.

Zhao, J; He, G; Huang, S; Villalobos, L F; Dakhchoune, M; Bassas, H; Agrawal, K V · Sci Adv · 2019

basic_science · Level V

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Abstract

One of the bottlenecks in realizing the potential of atom-thick graphene membrane for gas sieving is the difficulty in incorporating nanopores in an otherwise impermeable graphene lattice, with an angstrom precision at a high-enough pore density. We realize this design by developing a synergistic, partially decoupled defect nucleation and pore expansion strategy using O<sub>2</sub> plasma and O<sub>3</sub> treatment. A high density (ca. 2.1 × 10<sup>12</sup> cm<sup>-2</sup>) of H<sub>2</sub>-sieving pores was achieved while limiting the percentage of CH<sub>4</sub>-permeating pores to 13 to 22 parts per million. As a result, a record-high gas mixture separation performance was achieved (H<sub>2</sub> permeance, 1340 to 6045 gas permeation units; H<sub>2</sub>/CH<sub>4</sub> separation factor, 15.6 to 25.1; H<sub>2</sub>/C<sub>3</sub>H<sub>8</sub> separation factor, 38.0 to 57.8). This highly scalable pore etching strategy will accelerate the development of single-layer graphene-based energy-efficient membranes.