Hydrogen generation from hydrolysis of activated Al-Bi, Al-Sn powders prepared by gas atomization method

Highly activated Al-based composite powders with compositions of Al-20Bi and Al-20Sn (wt.%) were prepared by gas atomization method for hydrogen generation. The Al-20Bi powders formed incomplete core-shell structure with Bi aggregating on the powder surface, while the Al-20Sn powders presented eutectic structure with Sn distributed homogeneously on the grain boundaries of Al. The hydrolysis characteristics of these powders were investigated in distilled water. The results showed that the Al-20Bi and Al-20Sn powders exhibited high hydrolysis performance and violently reacted with distilled water at 30 °C. Elevated temperature could significantly shorten the incubation time, as well as improve hydrogen generation rate and conversion yield of the powders. The hydrolysis mechanism and oxidation resistance property of the powders were carefully investigated too. The miscibility gap and the large difference of linear thermal expansion coefficient between Al and Bi are responsible for the activation and high oxidation resistance of the Al-20Bi powders.