Hydrogenation properties of catalyzed and non-catalyzed magnesium films

The hydrogenation properties of 400 Å thick magnesium films, grown under ultra-high vacuum conditions, have been studied under conditions relevant for hydrogen storage, i.e., elevated temperatures and pressures. The hydrogen uptake of films modified by deposition of platinum on the magnesium surface was also investigated. A realistic hydrogen storage system is modeled by studying the combined effect on hydrogen sorption by a platinum catalyst and magnesium oxide, the latter a common impurity in magnesium-based hydrogen storage systems. Magnesium and platinum are found to inter-diffuse readily at room temperature. However, a partially oxidized magnesium layer stabilizes platinum on the surface, while still being permeable to hydrogen.