The Library
High-resolution ion-flux imaging of proton transport through graphene|nafion membranes
Tools
Tools
Tools
Bentley, Cameron Luke, Kang, Minkyung, Bukola, Saheed, Creager, Stephen E. and Unwin, Patrick R. (2022) High-resolution ion-flux imaging of proton transport through graphene|nafion membranes. ACS Nano, 16 (4). pp. 5233-5245. doi:10.1021/acsnano.1c05872 ISSN 1936-086X.
|
PDF
acsnano.1c05872.pdf - Published Version - Requires a PDF viewer. Available under License Creative Commons Attribution 4.0. Download (4Mb) | Preview |
Official URL: https://doi.org/10.1021/acsnano.1c05872
Abstract
In 2014, it was reported that protons can traverse between aqueous phases separated by nominally pristine monolayer graphene and hexagonal boron nitride (h-BN) films (membranes) under ambient conditions. This intrinsic proton conductivity of the one-atom-thick crystals, with proposed through-plane conduction, challenged the notion that graphene is impermeable to atoms, ions, and molecules. More recent evidence points to a defect-facilitated transport mechanism, analogous to transport through conventional ion-selective membranes based on graphene and h-BN. Herein, local ion-flux imaging is performed on chemical vapor deposition (CVD) graphene|Nafion membranes using an “electrochemical ion (proton) pump cell” mode of scanning electrochemical cell microscopy (SECCM). Targeting regions that are free from visible macroscopic defects (e.g., cracks, holes, etc.) and assessing hundreds to thousands of different sites across the graphene surfaces in a typical experiment, we find that most of the CVD graphene|Nafion membrane is impermeable to proton transport, with transmission typically occurring at ≈20–60 localized sites across a ≈0.003 mm2 area of the membrane (>5000 measurements total). When localized proton transport occurs, it can be a highly dynamic process, with additional transmission sites “opening” and a small number of sites “closing” under an applied electric field on the seconds time scale. Applying a simple equivalent circuit model of ion transport through a cylindrical nanopore, the local transmission sites are estimated to possess dimensions (radii) on the (sub)nanometer scale, implying that rare atomic defects are responsible for proton conductance. Overall, this work reinforces SECCM as a premier tool for the structure–property mapping of microscopically complex (electro)materials, with the local ion-flux mapping configuration introduced herein being widely applicable for functional membrane characterization and beyond, for example in diagnosing the failure mechanisms of protective surface coatings.
| Item Type: | Journal Article | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Subjects: | Q Science > QC Physics Q Science > QH Natural history Q Science > QP Physiology T Technology > TA Engineering (General). Civil engineering (General) T Technology > TS Manufactures |
||||||||||||||||||
| Divisions: | Faculty of Science, Engineering and Medicine > Science > Chemistry | ||||||||||||||||||
| SWORD Depositor: | Library Publications Router | ||||||||||||||||||
| Library of Congress Subject Headings (LCSH): | Scanning electrochemical microscopy, Two-dimensional materials , Nanopores , Protons , Chemical vapor deposition | ||||||||||||||||||
| Journal or Publication Title: | ACS Nano | ||||||||||||||||||
| Publisher: | American Chemical Society (ACS) | ||||||||||||||||||
| ISSN: | 1936-086X | ||||||||||||||||||
| Official Date: | 26 April 2022 | ||||||||||||||||||
| Dates: |
|
||||||||||||||||||
| Volume: | 16 | ||||||||||||||||||
| Number: | 4 | ||||||||||||||||||
| Page Range: | pp. 5233-5245 | ||||||||||||||||||
| DOI: | 10.1021/acsnano.1c05872 | ||||||||||||||||||
| Status: | Peer Reviewed | ||||||||||||||||||
| Publication Status: | Published | ||||||||||||||||||
| Access rights to Published version: | Restricted or Subscription Access | ||||||||||||||||||
| Copyright Holders: | Copyright © 2022 The Authors. Published by American Chemical Society | ||||||||||||||||||
| Date of first compliant deposit: | 17 November 2022 | ||||||||||||||||||
| Date of first compliant Open Access: | 17 November 2022 | ||||||||||||||||||
| RIOXX Funder/Project Grant: |
|
||||||||||||||||||
| Related URLs: |
Request changes or add full text files to a record
Repository staff actions (login required)
 |
View Item |
Downloads
Downloads per month over past year
