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InterfacialWater.pdf (2.88 MB)
Anomalously High Proton Conduction of Interfacial Water
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 18.01.2020, 10:22 and posted on 21.01.2020, 09:26by Vasily Artemov, Ece Uykur, Pavel Kapralov, Alexei Kiselev, Keith Stevenson, Henni Ouerdane, Martin Dressel
Water at the solid-liquid interface exhibits an anomalous ionic conductivity and dielectric constant compared to bulk water. Both phenomena still lack a detailed understanding. Here, we report radiofrequency measurements and analyses of the electrodynamic properties of interfacial water confined in nano-porous matrices formed by diamond grains of various sizes, ranging from 5 nm to 0.5 μm in diameter. Contrary to bulk water, the charge-carrying protons/holes in interfacial water are not mutually screened allowing for higher mobility in the external electric field. Thus, the protonic conductivity reaches a maximum value, which can be five orders of magnitude higher than that of bulk water. Our results aid in the understanding of physical and chemical properties of water confined in porous materials, and pave the way to the development of new type of highly-efficient proton-conductive materials for applications in electrochemical energy systems, membrane separations science and nano-fluidics.