Anisotropic Redox Conductivity within a Metal-Organic Framework Material

Subhadip Goswami, Idan Hod, Jiaxin Dawn Duan, Chung Wei Kung, Martino Rimoldi, Christos D. Malliakas, Rebecca H. Palmer, Omar K. Farha, Joseph T. Hupp

Research output: Contribution to journalArticle

Abstract

Engendering electrical conductivity in otherwise insulating metal-organic framework (MOF) materials is key to rendering these materials fully functional for a range of potential applications, including electrochemical and photo-electrochemical catalysis. Here we report that the platform MOF, NU-1000, can be made electrically conductive via reversible electrochemical oxidation of a fraction of the framework's tetraphenylpyrene linkers, where the basis for conduction is redox hopping. At a microscopic level, redox hopping is akin to electron self-exchange and is describable by Marcus' well-known theory of electron transfer. At a macroscopic level, the hopping behavior leads to diffusive charge transport and is quantifiable as an apparent diffusion coefficient, Dhopping. Theory suggests that the csq topology of NU-1000, together with its characteristic one-dimensional mesopores, will result in direction-dependent, that is, anisotropic, electrical conductivity. Detailed computations suggest that the governing factor is the strength of electronic coupling between pairs of linkers sited in the a,b plane of the MOF versus the mesopore-aligned c axis of the crystal. The notion has been put to the test experimentally by configuring the MOF as an array of selectively oriented, electrode-supported crystallites, where the rodlike crystallites are either oriented largely normal to the electrode (requiring redox hopping along the c direction) or mainly parallel (requiring redox hopping mainly through the a,b plane). The orientations are preselected by preparing MOF films either via interfacial solvothermal synthesis or via electrophoretic deposition. In semiquantitative accord with computational predictions, Dhopping is up to ∼3500 times larger in the c direction than through the a,b plane. In addition to their fundamental significance, the findings have clear implications for the design and optimization of MOFs for electrocatalysis and for other applications that rely upon electrical conductivity. ©

Original languageEnglish
JournalJournal of the American Chemical Society
DOIs
Publication statusAccepted/In press - Jan 1 2019

Fingerprint

Oxidation-Reduction
Metals
Electric Conductivity
Crystallites
Electrodes
Electrons
Electrocatalysis
Functional materials
Electrochemical oxidation
Catalysis
Charge transfer
Topology
Crystals
Direction compound

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Anisotropic Redox Conductivity within a Metal-Organic Framework Material. / Goswami, Subhadip; Hod, Idan; Duan, Jiaxin Dawn; Kung, Chung Wei; Rimoldi, Martino; Malliakas, Christos D.; Palmer, Rebecca H.; Farha, Omar K.; Hupp, Joseph T.

In: Journal of the American Chemical Society, 01.01.2019.

Research output: Contribution to journalArticle

Goswami, Subhadip ; Hod, Idan ; Duan, Jiaxin Dawn ; Kung, Chung Wei ; Rimoldi, Martino ; Malliakas, Christos D. ; Palmer, Rebecca H. ; Farha, Omar K. ; Hupp, Joseph T. / Anisotropic Redox Conductivity within a Metal-Organic Framework Material. In: Journal of the American Chemical Society. 2019.
@article{01f030f172eb439982832c3a814ccb7c,
title = "Anisotropic Redox Conductivity within a Metal-Organic Framework Material",
abstract = "Engendering electrical conductivity in otherwise insulating metal-organic framework (MOF) materials is key to rendering these materials fully functional for a range of potential applications, including electrochemical and photo-electrochemical catalysis. Here we report that the platform MOF, NU-1000, can be made electrically conductive via reversible electrochemical oxidation of a fraction of the framework's tetraphenylpyrene linkers, where the basis for conduction is redox hopping. At a microscopic level, redox hopping is akin to electron self-exchange and is describable by Marcus' well-known theory of electron transfer. At a macroscopic level, the hopping behavior leads to diffusive charge transport and is quantifiable as an apparent diffusion coefficient, Dhopping. Theory suggests that the csq topology of NU-1000, together with its characteristic one-dimensional mesopores, will result in direction-dependent, that is, anisotropic, electrical conductivity. Detailed computations suggest that the governing factor is the strength of electronic coupling between pairs of linkers sited in the a,b plane of the MOF versus the mesopore-aligned c axis of the crystal. The notion has been put to the test experimentally by configuring the MOF as an array of selectively oriented, electrode-supported crystallites, where the rodlike crystallites are either oriented largely normal to the electrode (requiring redox hopping along the c direction) or mainly parallel (requiring redox hopping mainly through the a,b plane). The orientations are preselected by preparing MOF films either via interfacial solvothermal synthesis or via electrophoretic deposition. In semiquantitative accord with computational predictions, Dhopping is up to ∼3500 times larger in the c direction than through the a,b plane. In addition to their fundamental significance, the findings have clear implications for the design and optimization of MOFs for electrocatalysis and for other applications that rely upon electrical conductivity. {\circledC}",
author = "Subhadip Goswami and Idan Hod and Duan, {Jiaxin Dawn} and Kung, {Chung Wei} and Martino Rimoldi and Malliakas, {Christos D.} and Palmer, {Rebecca H.} and Farha, {Omar K.} and Hupp, {Joseph T.}",
year = "2019",
month = "1",
day = "1",
doi = "10.1021/jacs.9b07658",
language = "English",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",

}

TY - JOUR

T1 - Anisotropic Redox Conductivity within a Metal-Organic Framework Material

AU - Goswami, Subhadip

AU - Hod, Idan

AU - Duan, Jiaxin Dawn

AU - Kung, Chung Wei

AU - Rimoldi, Martino

AU - Malliakas, Christos D.

AU - Palmer, Rebecca H.

AU - Farha, Omar K.

AU - Hupp, Joseph T.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Engendering electrical conductivity in otherwise insulating metal-organic framework (MOF) materials is key to rendering these materials fully functional for a range of potential applications, including electrochemical and photo-electrochemical catalysis. Here we report that the platform MOF, NU-1000, can be made electrically conductive via reversible electrochemical oxidation of a fraction of the framework's tetraphenylpyrene linkers, where the basis for conduction is redox hopping. At a microscopic level, redox hopping is akin to electron self-exchange and is describable by Marcus' well-known theory of electron transfer. At a macroscopic level, the hopping behavior leads to diffusive charge transport and is quantifiable as an apparent diffusion coefficient, Dhopping. Theory suggests that the csq topology of NU-1000, together with its characteristic one-dimensional mesopores, will result in direction-dependent, that is, anisotropic, electrical conductivity. Detailed computations suggest that the governing factor is the strength of electronic coupling between pairs of linkers sited in the a,b plane of the MOF versus the mesopore-aligned c axis of the crystal. The notion has been put to the test experimentally by configuring the MOF as an array of selectively oriented, electrode-supported crystallites, where the rodlike crystallites are either oriented largely normal to the electrode (requiring redox hopping along the c direction) or mainly parallel (requiring redox hopping mainly through the a,b plane). The orientations are preselected by preparing MOF films either via interfacial solvothermal synthesis or via electrophoretic deposition. In semiquantitative accord with computational predictions, Dhopping is up to ∼3500 times larger in the c direction than through the a,b plane. In addition to their fundamental significance, the findings have clear implications for the design and optimization of MOFs for electrocatalysis and for other applications that rely upon electrical conductivity. ©

AB - Engendering electrical conductivity in otherwise insulating metal-organic framework (MOF) materials is key to rendering these materials fully functional for a range of potential applications, including electrochemical and photo-electrochemical catalysis. Here we report that the platform MOF, NU-1000, can be made electrically conductive via reversible electrochemical oxidation of a fraction of the framework's tetraphenylpyrene linkers, where the basis for conduction is redox hopping. At a microscopic level, redox hopping is akin to electron self-exchange and is describable by Marcus' well-known theory of electron transfer. At a macroscopic level, the hopping behavior leads to diffusive charge transport and is quantifiable as an apparent diffusion coefficient, Dhopping. Theory suggests that the csq topology of NU-1000, together with its characteristic one-dimensional mesopores, will result in direction-dependent, that is, anisotropic, electrical conductivity. Detailed computations suggest that the governing factor is the strength of electronic coupling between pairs of linkers sited in the a,b plane of the MOF versus the mesopore-aligned c axis of the crystal. The notion has been put to the test experimentally by configuring the MOF as an array of selectively oriented, electrode-supported crystallites, where the rodlike crystallites are either oriented largely normal to the electrode (requiring redox hopping along the c direction) or mainly parallel (requiring redox hopping mainly through the a,b plane). The orientations are preselected by preparing MOF films either via interfacial solvothermal synthesis or via electrophoretic deposition. In semiquantitative accord with computational predictions, Dhopping is up to ∼3500 times larger in the c direction than through the a,b plane. In addition to their fundamental significance, the findings have clear implications for the design and optimization of MOFs for electrocatalysis and for other applications that rely upon electrical conductivity. ©

UR - http://www.scopus.com/inward/record.url?scp=85074232143&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85074232143&partnerID=8YFLogxK

U2 - 10.1021/jacs.9b07658

DO - 10.1021/jacs.9b07658

M3 - Article

C2 - 31608628

AN - SCOPUS:85074232143

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

ER -