Hydrogen generation by hydrolysis of Al–Li–Bi–NaCl mixture with pure water

In the present work, the Al–Bi–Li mixtures were prepared by a milling processing, using NaCl as the milling-assisted agent, and the hydrogen evolution characteristics of the as-prepared Al-based mixtures with pure water were evaluated. The results showed that the addition of Li could significantly improve the hydrolysis rate of Al-based mixtures and increase the amount of generated hydrogen. When the amount of Li was increased up to 4 wt%, 1 g Al-based mixture could yield 1.38 SL hydrogen which was higher than that generated from pure Al and water. The powder X-ray diffraction analysis indicated that some new phases, namely BiLi 3 and AlLi, were formed during the milling process. The enhanced hydrolysis rate of Al-based mixtures was mostly attributed to the presence of these new phases because they might act as an active reaction center in water. The apparent activation energy calculated from the as-obtained hydrogen evolution kinetic data also supported such an explanation. The hydrolysis products of Al-based mixtures were Al(OH) 3 (bayerite), Bi and LiAl 2(OH) 7·2H 2O, whereas only AlOOH (boehmite) was observed for the system without addition of Li, indicating that the addition of Li did increase the hydroxyl ions concentration during the hydrolysis process. ► The addition of Li could improve the hydrolysis rate of Al-based mixtures and increase the amount of generated hydrogen. ► 1 g of the as-obtained Al-based mixture could maximally yield 1.38 SL hydrogen. ► The as-formed BiLi 3 and AlLi phases acting as an active reaction center can enhance the hydrogen generation reaction.