热处理对LaNi_(4.25)Al_(0.75)/SiO_2复合材料储氢特性的影响

Effect of Heat Treatment Temperature on Hydrogen Storage Properties of of LaNi_(4.25)Al_(0.75)/SiO_2 Composite Composite

采用气相二氧化硅法制备了LaNi4.25Al0.75/SiO2复合材料。研究了该复合材料经不同温度(473～1 073K)热处理后的相组成、形貌及吸放氢p-C-T曲线、吸氢动力学性能和吸放氢循环性能。结果表明,随着热处理温度的升高,LaNi4.25Al0.75/SiO2复合材料吸氢量减少,平台压升高,平台斜率略有增加,而动力学性能并无显著变化。经60次吸放氢循环后,经不同温度热处理后的样品均未出现粉化现象,且与未循环样品储氢性能基本保持一致。

LaNi4.25Al0.75/SiO2 composite was prepared by fumed silica method. The effect of heat treatment temperature （473-1 073 K） on phase composition, microstruc- ture, 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.