Abstract
Here, we describe the installation of a ferrocene derivative on and within the archetypal metal-organic framework (MOF), UiO-66, by solvent-assisted ligand incorporation. Thin films of the resulting material show a redox peak characteristic of the Fc/Fc+ couple, as measured by cyclic voltammetry. Consistent with restriction of redox reactivity solely to Fc molecules sited at or near the external surfaces of MOF crystallites, chronoamperometry measurements indicate that less than 20% of the installed Fc molecules are electrochemically active. Charge-transport diffusion coefficients, DCT, of 6.1 ± 0.8 × 10-11 and 2.6 ± 0.2 × 10-9 cm2/s were determined from potential step measurements, stepping oxidatively and reductively, respectively. The 40-fold difference in DCT values contrasts with the expectation, for simple systems, of identical values for oxidation-driven versus reduction-driven charge transport. The findings have implications for the design of MOFs suitable for delivery of redox equivalents to framework-immobilized electrocatalysts and/or delivery of charges from a chromophoric MOF film to an underlying electrode, processes that may be central to MOF-facilitated conversion of solar energy to chemical or electrical energy.
| Original language | English |
|---|---|
| Pages (from-to) | 4707-4714 |
| Number of pages | 8 |
| Journal | Langmuir |
| Volume | 34 |
| Issue number | 16 |
| DOIs | |
| State | Published - 24 Apr 2018 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2018 American Chemical Society.
Funding
We gratefully acknowledge support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences (Grant No. DE-FG02-87ER13808) and Northwestern University. R.H.P. acknowledges support from the National Science Foundation Graduate Research Fellowship program under Grant No. DGE-1324585. This work made use of the EPIC facility of the NUANCE Center at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. This work also made use of the J.B. Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1121262) at the Materials Research Center of Northwestern University. We gratefully acknowledge support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences (Grant No. DE-FG02-87ER13808) and Northwestern University. R.H.P. acknowledges support from the National Science Foundation Graduate Research Fellowship program under Grant No. DGE-1324585. This work made use of the EPIC facility of the NUANCE Center at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN.
| Funders | Funder number |
|---|---|
| Soft and Hybrid Nanotechnology Experimental | |
| National Science Foundation | DGE-1324585, NNCI-1542205 |
| U.S. Department of Energy | |
| W. M. Keck Foundation | |
| Ecumenical Project for International Cooperation | |
| Office of Science | |
| Basic Energy Sciences | DE-FG02-87ER13808 |
| Northwestern University | |
| Materials Research Science and Engineering Center, Harvard University | DMR-1121262 |
| Norsk Sykepleierforbund |