Reaction and desorption kinetics of H2 and H2O on activated and non-activated palladium surfaces

The permeation/desorption of hydrogen and the reaction between oxygen and permeating/desorbing hydrogen from a polycrystalline palladium sample have been studied under ultra-high vacuum conditions. Furthermore, the effects of potassium on desorption and reaction has been investigated. Time-of-flight spectroscopy has been mainly used to determine the translational energy distribution of desorption and reaction products. These experiments were complemented by angular distribution measurements. It turned out that the associative hydrogen desorption is inactivated on the clean palladium, but activated on the potassium-covered surface. The water formation/desorption is inactivated on both, the clean and the potassium-covered surfaces.