Preparation of A2B7-type La-Mg-Ni Hydrogen Storage Alloy and Its Catalytic Oxidation Performance for BH4 -

Abstract

The La-Mg-Ni hydrogen storage alloys with A2B7/AB5 double phase were successfully prepared by vacuum melting combined with ball milling. The phase structure, electrochemical properties and the catalytic oxidation properties for BH4- of the (Mm1-xMgx)Ni2.485Co0.525Mn0.28Al0.21 (x=0.1-0.5 )alloys were investigated by XRD and electrochemical measurements. The results showed that (Mm1-xMgx)Ni2.485Co0.525Mn0.28Al0.21 alloys are composed of LaNi5 phase and (La, Mg)2Ni7 phase. Among the studied alloys, the electrochemical properties of the alloy with x=0.3 is the best, and the electrochemical properties of the alloy with x=0.3 is significantly better than that of the AB5-type hydrogen storage alloy, which is mainly due to the formation of (La, Mg)2Ni7 phase in the alloy. At the same time, the alloy with x=0.3 also shows a better catalytic oxidation effect on BH4-, which is also better than that of the AB5- type hydrogen storage alloy. The catalysis of (Mm1-xMgx)Ni2.485Co0.525Mn0.28Al0.21 alloy catalyst is related to its electrochemical performance. The catalysis of hydrogen storage alloys may have a positive correlation with its own electrochemical performance.