In situ impedance study of the Y–Ni thin film under electrochemical hydrogenation

A thin film of yttrium Y (150 nm) protected by a 6 nm coating of nickel Ni on a glass substrate was completely hydrogenated in a 1 M NaOH electrolyte at a constant negative current until the transparent Y tri-hydride phase was achieved and hydrogen gas evolution from the electrode began. A series of...

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Bibliographic Details
Published in:Electrochimica acta 2005-11, Vol.51 (4), p.720-724
Main Authors: Matveeva, Eugenia, Parkhutik, Vitali
Format: Article
Language:English
Subjects:
Chemistry
Electrochemistry
Electrodes: preparations and properties
Equivalent electrical circuit analysis
Exact sciences and technology
General and physical chemistry
Hydrogenation
Impedance
Ni protection
Other electrodes
Y thin film
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Summary:A thin film of yttrium Y (150 nm) protected by a 6 nm coating of nickel Ni on a glass substrate was completely hydrogenated in a 1 M NaOH electrolyte at a constant negative current until the transparent Y tri-hydride phase was achieved and hydrogen gas evolution from the electrode began. A series of impedance measurements were performed in situ during the electrochemical experiment to study the properties of the system as dependent on hydrogenation degree and time of relaxation. The equivalent electrical circuit (EEC) simulations were performed with a Randles-like scheme R 0[ R 1CPE 1], where R 0 is the thin film electrode resistance, R 1 the charge transfer resistance and CPE 1 is the capacitive constant phase element. The behavior of all the components of the EEC undergoes a clear transition when the hydrogenation degree of the electrode is approximated to its maximum value (H to Y ratio 2.7) and electrochemical process changes from hydrogen uptake to hydrogen evolution.
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2005.05.036