H2 reactivity on the surface of LaNi4.7Sn0.3

The influence of O2 and H2O on the hydrogen reactivity with the surface of LaNi4.7Sn0.3 was studied at 298 K by a volumetric Wagener method. A significant enhancement of the H2 reactivity by precovering the surface by both O2 and H2O was observed. A formation of the oxygen deficient SnO2−x in the surface layer acting as a catalyser of the H2 dissociation stands as possible reason for such an improvement. The present data explain the reasons for the improvement of hydrogen cycling properties by the Sn-doped LaNi5 alloys.