Hydrolysis of ball milling Al–Bi–hydride and Al–Bi–salt mixture for hydrogen generation

In this paper, an effective method to produce hydrogen via the hydrolysis of the milled Al–Bi–hydride (or salts) in pure water at room temperature has been found. The result shows that the Al–Bi–hydrides (or salts) prepared by 5 h milling appear very effective to improve their hydrolysis reactivity. And the milled Al–Bi–hydrides (or salts) have high hydrogen yield in pure water, especially the Al–10 wt.% Bi–10 wt.% MgH2 mixture or Al–10 wt.% Bi–10 wt.% MgCl2 mixture all can produce 1050 ml/g within 5 min. The improvement mainly comes from three factors: (1) the additives (MgH2, CaH2, LiCl, MgCl2, KCl, etc.) play an important role to decrease the mean size of the mixture particles; (2) the exothermic dissolution of the salt additive such as MgCl2 can increase the temperature of aqueous solution, favoring the reaction between Al–Bi composite and water; (3) the hydrolysis of the additives can also offer conductive ions on the work of the micro-galvanic cell of Al–Bi composite. Furthermore, the high conductive ions around the Al–Bi composite are the uppermost effect for increasing the hydrogen yield and hydrogen generation rate.