Study on electrochemical absorption of hydrogen in palladium and its alloys using limited volume electrodes

The review summarizes the results of the electrochemical studies on hydrogen absorption in Pd and Pd alloys prepared in the form of thin deposits on a hydrogen -neutral matrix. This kind of electrodes, called Limited Volume Electrodes (LVE), enables to limit and control the amount of absorbed hydrogen inside a Pd sample and makes it possible to study the process of hydrogen absorption under electrochemical conditions. The amount of absorbed hydrogen, phase transition potentials, hysteresis effect and the rate of hydrogen absorption/desorption can be determined using cyclic voltammetric, chronoamperometric and chronopotentiometric techniques. The mechanism of the interactions of hydrogen with Pd-LVE is presented. The influence of electrode potential, temperature and Pd layer thickness on the process of hydrogen absorption is discussed. The behavior of Pd alloys towards hydrogen is summarized. The interrelation between hydrogen absorption and surface processes is described. The examples of the use of LVE in applied electrochemistry are given