Interface mixing and hydrogen absorption in Pd/Mg and Pd/Al/Mg thin films

• Published in: International journal of hydrogen energy 2021-01, Vol.46 (1), p.806-813
• Main Authors: Pacanowski, S., Wachowiak, M., Jabłoński, B., Szymański, B., Smardz, L.
• Format: Article
• Language: English
• Subjects: Hydrogen absorption; Metallic multilayers; Mg thin films; XPS
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.09.175

Pd/Mg bilayers and Pd/Al/Mg trilayers were prepared onto glass substrates at room temperature (RT) by UHV magnetron sputtering. Mixing effects at the Pd–Mg and Al–Mg interfaces were studied in-situ, immediately after deposition, by X-ray Photoelectron Spectroscopy (XPS). Additionally, the interfaces of the Pd/Al/Mg trilayer for the Al thickness equal to 1 nm were examined. Hydrogen absorption was monitored in-situ at RT by simultaneous resistivity and optical transmittance measurements. Formation of MgH2 phase was confirmed by ex-situ X-ray diffraction measurements. The XPS studies revealed rather sharp interface between Al and Mg layers. On the other hand, a significant interface mixing for the Pd/Mg bilayers and Pd/1 nm – Al/Mg trilayers was observed. Further studies showed that an additional layer of Al, deposited between magnesium and palladium layers, can significantly improve the hydrogen absorption kinetics at RT. The optimal thickness of the Al layer was found to be 0.5 nm. •Interface mixing for the Pd/Mg bilayers and Pd/Al/Mg trilayers was studied in-situ by XPS.•Hydrogen absorption was monitored in-situ by resistivity and transmittance measurements.•The Pd/Al/Mg trilayers showed significantly improved hydrogenation kinetics at room temperature.