Measuring the Proton Selectivity of Graphene Membranes
Applied Physics Letters
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Walker, M., Braeuninger-Weimer, P., Weatherup, R., Hofmann, S., & Keyser, U. (2015). Measuring the Proton Selectivity of Graphene Membranes. Applied Physics Letters, 107 (213104)https://doi.org/10.1063/1.4936335
By systematically studying the proton selectivity of free-standing graphenemembranes in aqueous solutions, we demonstrate that protons are transported by passing through defects. We study the current-voltage characteristics of single-layer graphene grown by chemical vapour deposition(CVD) when a concentration gradient of HCl exists across it. Our measurements can unambiguously determine that H⁺ ions are responsible for the selective part of the ionic current. By comparing the observed reversal potentials with positive and negative controls, we demonstrate that the as-grown graphene is only weakly selective for protons. We use atomic layer deposition to block most of the defects in our CVDgraphene. Our results show that a reduction in defect size decreases the ionic current but increases proton selectivity.
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (656870)
External DOI: https://doi.org/10.1063/1.4936335
This record's URL: https://www.repository.cam.ac.uk/handle/1810/252710