CATALYTIC EFFECT IN THE HYDROGENATION OF MG AND MG COMPOUNDS - SURFACE-ANALYSIS OF MG-MG2NI AND MG2NI+

By means of XPS and AES we have analysed the chemical states and the concentrations of Mg and Ni at the surface of the hydrogen storage materials MgMg2Ni eutectic alloy and Mg2Ni intermetallic compound. Mg2Ni decomposes at the surface into Mg oxide and metallic Ni. Molecular hydrogen can be dissociated at the metallic Ni precipitations or at the metallic subsurface layer. Thus the proposed model describes the catalytic effect of Mg2Ni on the hydrogenation [1] of Mg by surface decomposition and the ability to supply atomic hydrogen. With a similar model we described already successfully catalytic effects at the surface of LaNi5 and FeTi [2]. It is likely that it is applicable to other Mg compounds, too. © 1979.