Abstract
Hydrogen may be adsorbed on Pt while it can be adsorbed on and absorbed in Pd and its alloys. Kinetics of hydrogen adsorption on Pt and Pd-Pt alloys is very fast but it is much slower on Pd. The kinetics of these reactions was studied using the electrochemical impedance spectroscopy, EIS, with a twin electrode configuration. The studies in the presence of crystal violet, which poisons hydrogen adsorption and accelerates hydrogen absorption, indicate that the absorption process proceeds via direct absorption mechanism.