Hydrogen generation from Al/NaBH_4 hydrolysis promoted by Li-NiCl_2 additives

摘要

On-demand hydrogen generation from solid-state Al/NaBH_4 hydrolysis activated by Li-NiCl_2 additives are elaborated in the present paper. Hydrogen generation amount and rate can be regulated by changing Al/NaBH_4 weight ratio, Li and NiCl_2 amount, hydrolytic temperature, etc. The optimized Al-10 wt.% Li-15 wt.% NiCl_2/NaBH_4 mixture (weight ratio of 1:1) yields 1778 ml hydrogen/1 g mixture with 100% efficiency within 50 min at 323 K. The improved hydrolytic performance comes from the effect of Li-NiCl_2 additives, which decrease aluminum particle size in the milling process and produce the catalytic promoter BNi_2/Al(OH)_3 in the hydrolytic process. Compared with the conventional reaction of Al and NaBH_4 in water, there is an interaction of Al/NaBH_4 hydrolysis which improves the hydrolytic kinetics of Al/NaBH_4 via the catalytic effect of hydrolysis by-products Al(OH)_3, BNi_2, and NaBO_2. The Al/NaBH_4 mixture may be applied as a portable hydrogen generation material. Our experimental data lay a foundation for designing practical hydrogen generators.