Direct observation of the dynamics of single metal ions at the interface with solids in aqueous solutions
Ricci, M.; Trewby, W.; Cafolla, M.; Voïtchovsky, K.
Dr Miro Cafolla firstname.lastname@example.org
Addison Wheeler Research Fellow
Professor Kislon Voitchovsky email@example.com
The dynamics of ions adsorbed at the surface of immersed charged solids plays a central role in countless natural and industrial processes such as crystal growth, heterogeneous catalysis, electrochemistry, or biological function. Electrokinetic measurements typically distinguish between a so-called Stern layer of ions and water molecules directly adsorbed on to the solid’s surface, and a diffuse layer of ions further away from the surface. Dynamics within the Stern layer remain poorly understood, largely owing to a lack of in-situ atomic-level insights. Here we follow the dynamics of single Rb+ and H3O+ ions at the surface of mica in water using high-resolution atomic force microscopy with 25 ms resolution. Our results suggest that single hydrated Rb+ions reside τ1 = 104 ± 5 ms at a given location, but this is dependent on the hydration state of the surface which evolves on a slower timescale of τ2 = 610 ± 30 ms depending on H3O+ adsorption. Increasing the liquid’s temperature from 5 °C to 65 °C predictably decreases the apparent glassiness of the interfacial water, but no clear effect on the ions’ dynamics was observed, indicating a diffusion-dominated process. These timescales are remarkably slow for individual monovalent ions and could have important implications for interfacial processes in electrolytes.
Ricci, M., Trewby, W., Cafolla, M., & Voïtchovsky, K. (2017). Direct observation of the dynamics of single metal ions at the interface with solids in aqueous solutions. Scientific Reports, 7, Article 43234. https://doi.org/10.1038/srep43234
|Journal Article Type||Article|
|Acceptance Date||Jan 23, 2017|
|Online Publication Date||Feb 23, 2017|
|Publication Date||Feb 23, 2017|
|Deposit Date||Nov 21, 2016|
|Publicly Available Date||Mar 2, 2017|
|Peer Reviewed||Peer Reviewed|
Published Journal Article
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This work is licensed under a Creative Commons Attribution 4.0 International License. The images<br /> or other third party material in this article are included in the article’s Creative Commons license,<br /> unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license,<br /> users will need to obtain permission from the license holder to reproduce the material. To view a copy of this<br /> license, visit http://creativecommons.org/licenses/by/4.0/<br /> © The Author(s) 2017.
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