Kinetics and mechanism of hydrogen electrosorption in palladium-based alloys

Thin layers of Pd and its alloys with Rh, Pt, Au, Ag and Cu were prepared by electrodeposition on Au substrate. Hydrogen absorption in the obtained electrodes was studied in 0.5 H2SO4 aq and 0.1 M NaOH aq, using cyclic voltammetry and chronoamperometry. The influence of alloying process on the kinetics of hydrogen absorption and desorption was examined. Hydrogen diffusion coefficient in the α-phase was calculated for Pd-based electrodes from the analysis of chronoamperometric curves recorded during absorbed hydrogen oxidation. The effect of scan rate on absorbed hydrogen oxidation charge for different alloys was compared and discussed. CO adsorption was applied as a diagnostic tool for the examination of the mechanism of hydrogen removal from the electrodes studied.