Hydrogen adsorption/absorption in palladium thin deposits on gold electrode, in 0.1 M NaOH solution, was studied. The contributions ofadsorption and absorption to the total charge ofhydrogen are separated from the total isotherms at different deposit thicknesses. The adsorbed hydrogen charge increases to a plateau of-73.5 RC cm-2, which corresponds to the surface coverage ratio by adsorbed hydrogen ofO.36. The absorbed hydrogen charge agreed with that obtained from the permeation experiments at 50 [Lm Pd foil, at potentials between +100 and +300 mV vs. RHE. EIS was carried out at thin Pd deposits. The kinetics of hydrogen sorption is slower in alkaline solutions than in acids and the isotherms are shifted towards more negative potentials. (c) 2008 Elsevier Ltd. All rights reserved.