MlNi_4Co_(0.6)Al_(0.4)储H_2合金表面吸H_2的TDS研究

用热脱附谱 (TDS)对不同表面处理的富La混合储H2 合金MlNi4 Co0 6Al0 4 粉末样品进行H2 气吸附和脱附特性的比较和研究。未经表面处理的粉末样品 ,只测到一个H2 脱附峰 (α峰 ) ,脱附温度在 40 0K左右 ;经 6molKOH溶液 ,在 80℃下处理 6h的MlNi4 Co0 6Al0 4 粉末样品 ,有 2个H2 热脱附峰 (β峰和γ峰 ) ,脱附温度分别在 5 40和 6 30K处 ;而用 6molKOH 0 0 2molKBH4 溶液处理后 ,则有 3个H2 热脱附峰 (α峰 ,β峰和γ峰 ) ,脱附温度分别在 40 0 ,5 30和 6 40K处。TDS研究表明 ,热碱加还原的处理使材料表面对H2 气吸附的活性和容量提高 ,并使各个吸附态的扩散和转变更加容易。

Thermal Desorption of H_2 on Alkaline Pretreatment MlNi_4Co_(0.6) Al_(0.4) Hydrogen Storage Alloy

Adsorption and desorption of hydrogen on the surface of the hydrogen storage alloy powders, MlNi4Co0.6Al0.4(where Ml is La-rich rare-earth metal mixture of La(64.4),Pr(26.6),and Nd(2.24)in percentage weight) with and without surface treatment,were studied with thermal desorption spectroscopy(TDS).Before the surface treatment,only one adsorption state of H2(α)was observed at about 400 K.However,after the treatment of MlNi4Co0.6Al0.4 powder in 6 mol KOH solution for 6 hours at 350 K,too more H2 desorption states(β and γ)were observed at temperatures of 530 K and 640 K,respectively.After the surface treatment of the powder in a mixture of 6 mol KOH +0.02 mol KBH4 solution,three adsorption states(α,β and γ)can be observed at the desorption temperatures of 400 K,549 K and 630 K,respectively.The TDS results show that alkaline pretreatment may considerably improve the activity and capacity of hydrogen adsorption on the MlNi4Co0.6Al0.4 hydrogen storage alloy.