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A DNA-Threaded ZIF-8 Membrane with High Proton Conductivity and Low Methanol Permeability

TitleA DNA-Threaded ZIF-8 Membrane with High Proton Conductivity and Low Methanol Permeability
Publication TypeJournal Article
Year of Publication2018
AuthorsGuo, Y, Jiang, Z, Ying, W, Chen, L, Liu, Y, Wang, X, Jiang, ZJ, Chen, B, Peng, X
JournalAdv Mater
Date PublishedJan
ISBN Number0935-9648
Accession Number29193330
KeywordsDNA-threaded DNA@ZIF-8 membranes, fast proton transportation, high proton conductivity, low methanol permeability

Natural biomolecules have potential as proton-conducting materials, in which the hydrogen-bond networks can facilitate proton transportation. Herein, a biomolecule/metal-organic framework (MOF) approach to develop hybrid proton-conductive membranes is reported. Single-strand DNA molecules are introduced into DNA@ZIF-8 membranes through a solid-confined conversion process. The DNA-threaded ZIF-8 membrane exhibits high proton conductivity of 3.40 x 10(-4) S cm(-1) at 25 degrees C and the highest one ever reported of 0.17 S cm(-1) at 75 degrees C, under 97% relatively humidity, attributed to the formed hydrogen-bond networks between the DNA molecules and the water molecules inside the cavities of the ZIF-8, but very low methanol permeability of 1.25 x 10(-8) cm(2) s(-1) due to the small pore entrance of the DNA@ZIF-8 membranes. The selectivity of the DNA@ZIF-8 membrane is thus significantly higher than that of developed proton-exchange membranes for fuel cells. After assembling the DNA@ZIF-8 hybrid membrane into direct methanol fuel cells, it exhibits a power density of 9.87 mW cm(-2) . This is the first MOF-based proton-conductivity membrane used for direct methanol fuel cells, providing bright promise for such hybrid membranes in this application.