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Controlled Hydrogen Loading of Magnesium Thin Films in KOH—Effects on the Hydride Nucleation and Growth Regimes

Guardi, Giorgia 1; Sarapulova, Angelina 2; Dsoke, Sonia ORCID iD icon 2; Wagner, Stefan 1; Pasquini, Luca; Pundt, Astrid 1
1 Institut für Angewandte Materialien – Werkstoffkunde (IAM-WK), Karlsruher Institut für Technologie (KIT)
2 Institut für Angewandte Materialien – Energiespeichersysteme (IAM-ESS), Karlsruher Institut für Technologie (KIT)

Abstract:

In this work, we propose a strategy to optimize electrochemical hydrogen loading in magnesium–palladium thin films, using 5 M KOH as an electrolyte. Mg thin films of thickness 26 nm were deposited on sapphire (0001) substrates and capped by a 32 nm Pd layer. By performing cyclic voltammetry with in situ optical microscopy, it appears that a loading potential of at least −1.2 V vs. Hg/HgO has to be achieved at the sample’s surface to trigger magnesium hydride formation. Loading potential effects are then further explored by hydrogenography, where different hydride formation mechanisms appear based on the actual potential. With a larger loading potential of −1.6 V vs. Hg/HgO, a magnesium hydride blocking layer is formed; in this case, Pd hydride temporarily forms in the capping layer as hydrogen diffuses towards the magnesium layer. Loading is optimized for a lower potential of −1.2 V vs. Hg/HgO, which leads to larger hydride precipitates and delays the blocking layer formation; in this case, Pd hydride only appears after the magnesium layer is completely hydrided.

Zugehörige Institution(en) am KIT Institut für Angewandte Materialien – Energiespeichersysteme (IAM-ESS)
Institut für Angewandte Materialien – Werkstoffkunde (IAM-WK)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2024
Sprache Englisch
Identifikator ISSN: 2673-8023
KITopen-ID: 1000178499
Erschienen in Micro
Verlag MDPI AG (MDPI AG)
Band 4
Heft 4
Seiten 765 – 777
Vorab online veröffentlicht am 05.12.2024
Nachgewiesen in Scopus
Dimensions

Verlagsausgabe §
DOI: 10.5445/IR/1000178499
Veröffentlicht am 29.01.2025
Seitenaufrufe: 14
seit 29.01.2025
Downloads: 9
seit 30.01.2025
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