Tuning the Transport Properties of Gases in Porous Graphene Membranes with Controlled Pore Size and Thickness.

Autor: Ashirov T; Department of Chemistry, University of Fribourg, Fribourg, 1700, Switzerland., Yazaydin AO; Department of Chemical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK., Coskun A; Department of Chemistry, University of Fribourg, Fribourg, 1700, Switzerland.
Jazyk: angličtina
Zdroj: Advanced materials (Deerfield Beach, Fla.) [Adv Mater] 2022 Feb; Vol. 34 (5), pp. e2106785. Date of Electronic Publication: 2021 Dec 12.
DOI: 10.1002/adma.202106785
Abstrakt: Porous graphene membranes have emerged as promising alternatives for gas-separation applications due to their atomic thickness enabling ultrahigh permeance, but they suffer from low gas selectivity. Whereas decreasing the pore size below 3 nm is expected to increase the gas selectivity due to molecular sieving, it is rather challenging to generate a large number of uniform small pores on the graphene surface. Here, a pore-narrowing approach via gold deposition onto porous graphene surface is introduced to tune the pore size and thickness of the membrane to achieve a large number of small pores. Through the systematic approach, the ideal combination is determined as pore size below 3 nm, obtained at the thickness of 100 nm, to attain high selectivity and high permeance. The resulting membrane shows a H 2 /CO 2 separation factor of 31.3 at H 2 permeance of 2.23 × 10 5 GPU (1 GPU = 3.35 × 10 -10  mol s -1 m -2 Pa -1 ), which is the highest value reported to date in the 10 5 GPU permeance range. This result is explained by comparing the predicted binding energies of gas molecules with the Au surface, -5.3 versus -21 kJ mol -1 for H 2 and CO 2 , respectively, increased surface-gas interactions and molecular-sieving effect with decreasing pore size.
(© 2021 The Authors. Advanced Materials published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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