Effect of Heat Treatment Temperature on Hydrogen Storage Properties of LaNi_4.25Al_0.75/SiO₂ Composite

A LaNi_4.25Al_0.75/SiO₂ composite was prepared by fumed silica method. The effect of heat treatment temperature (473-1 073 K) on phase composition, microstructure, hydrogen absorption/desorption pressure-composition isotherms (p-C-T curves), hydrogen absorption kinetics and absorption/desorption cycling properties of this composite was studied. The results indicate that with increasing the heat treatment temperature, hydrogen uptake capacity decreases, p-C-T plateau pressure and plateau slope increase slightly, while absorption kinetics almost keeps stable. After 60 cycles of hydrogen absorption/desorption the composite heat treated at all studied temperatures do not pulverize, and the hydrogen storage properties do not show significant difference from that of the as prepared.