Unexpected Behavior of the Hydrogen Oxidation Reaction on Palladium in Alkaline Solution: A Feasible Kinetic Explanation

Abstract

The hydrogen oxidation reaction was studied on a thin film palladium electrode supported on a gold substrate in alkaline solution. The hydrogen absorption process was analyzed by open circuit potential transient and the current - overpotential dependences were obtained by chronoamperometry at different rotation rates in a solution saturated with hydrogen. The results obtained show anunexpected profile at low overpotentials, where current decreases as rotation rate increases. A kinetic mechanism was proposed to interpret this behavior and the corresponding equations were derived. They were used to correlate the results, with a good agreement between the experimental and fitted curves.