Franceschi, G., Brandstetter, S., Balajka, J., Sokolović, I., Pavelec, J., Setvin, M., Schmid, M., & Diebold, U. (2024). Interaction of surface cations of cleaved mica with water in vapor and liquid forms. Faraday Discussions, 249, 84–97. https://doi.org/10.1039/D3FD00093A
E134-05 - Forschungsbereich Surface Physics E056-04 - Fachbereich TU-DX: Towards Applications of 2D Materials
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Journal:
Faraday Discussions
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ISSN:
1359-6640
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Date (published):
2024
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Number of Pages:
14
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Publisher:
ROYAL SOC CHEMISTRY
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Peer reviewed:
Yes
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Keywords:
mica; water; nc-AFM; mineral surfaces; ion hydration
en
Abstract:
Natural minerals contain ions that become hydrated when they come into contact with water in vapor and liquid forms. Muscovite mica – a common phyllosilicate with perfect cleavage planes – is an ideal system to investigate the details of ion hydration. The cleaved mica surface is decorated by an array of K+ ions that can be easily exchanged with other ions or protons when immersed in an aqueous solution. Despite the vast interest in the atomic-scale hydration processes of these K+ ions, experimental data under controlled conditions have remained elusive. Here, atomically resolved non-contact atomic force microscopy (nc-AFM) is combined with X-ray photoelectron spectroscopy (XPS) to investigate the cation hydration upon dosing water vapor at 100 K in ultra-high vacuum (UHV). The cleaved surface is further exposed to ultra-clean liquid water at room temperature, which promotes ion mobility and partial ion-to-proton substitution. The results offer the first direct experimental views of the interaction of water with muscovite mica in UHV. The findings are in line with previous theoretical predictions.