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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 16 (2011) pp 138-142

Application of Thin Layer of Metal Deposit for Easy Study on Hydrogen Electrosorption in Palladium

Andrzej Czerwiński* and Mariusz Łukaszewski

Warsaw University, Department of Chemistry, Pasteura 1, 02-093 Warsaw, Poland, aczerw@chem.uw.edu.pl
Received September 27, 2010. Accepted February 27, 2011.

Published: 2 June 2011

Abstract. This paper demonstrates the methodology of the investigations on electrochemical behavior of hydrogen-absorbing materials using a Pd-limited volume electrode (LVE) as an example and model system. An experiment for physical chemistry students is described, in which they prepare Pd-LVE by electrodeposition of a thin metal layer on Au matrix, and examine the influence of electrode potential on the amount of hydrogen electrochemically absorbed in Pd from 0.5 M H₂SO₄ solution. The potential ranges corresponding to a- and b-phase existence as well as the a-b phase transition can be easily distinguished. Hysteresis between hydrogen absorption and desorption is illustrated. The comparison between electrochemical behavior of Pd-LVE and bulk Pd electrode is also made, demonstrating the unique advantages of the use of LVE in the electrochemical studies on hydrogen-absorbing materials. Chronoamperometry and cyclic voltammetry are used as experimental techniques together with the application of Faraday law of electrolysis coupled with classical gravimetry. The experiment allows the students to learn on some important topics of solid state chemistry and electrochemistry; i.e. hydrogen absorption in metals, non-stoichiometric compounds, metal deposition, phase transition, thin layer electrodes.

Key Words: Laboratories and Demonstrations; physical chemistry; electrochemistry; hydrogen absorption; experimental studies; palladium-limited volume electrode

(*) Corresponding author. (E-mail: aczerw@chem.uw.edu.pl)

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