Effect of temperature on hydrogen generation and hydrolysis mechanism of Al–Sn–Bi composite materials

Abstract

To prepare a kind of Al-based composite materials with high hydrogen performance, this study characterizes the influence of temperature on Al alloy's hydrogen generation performance and investigates the role of bismuth (Bi) and tin (Sn) in hydrogen generation. Hydrogen testing reveals that the hydrogen properties of Al–Sn–Bi composite materials are significantly improvs at 75 °C than they are at 50 °C. Al-3wt% Sn-7wt% Bi composite material, which has a hydrogen generation rate of 1620 mL·g−1·min−1 and activation energy of 39.06 kJ·mol−1, exhibits the best hydrogen performance. XRD results indicate that Sn and Bi play a role in promoting the Al/H2O reaction. SEM results show that hydrolysates are primarily fibrous Al(OH)3 at 50 °C, whereas honeycomb AlOOH and fibrous Al(OH)3 at 75 °C. In the reaction hydrolysates, AlOOH can promote the Al/H2O reaction, while Al(OH)3 is attached to the surface of AlOOH and inhibits the Al/H2O reaction.