Hydrogen generation by aluminum hydrolysis using the Fe2Al5 intermetallic compound

• Ball-milling allows the intermetallic activation and the hydrogen generation reaction take place.
• Aluminum from Fe2Al5 intermetallic reacts with aqueous solutions to release gas hydrogen.
• The pH increase of the solution leads to hydrogen amount increase.

Intermetallic phases with high aluminum content release hydrogen naturally; this is due to their susceptibility to hydrogen environmental embrittlement. Thus, in this work we take advantage of this phenomenon to assess hydrogen generation using the Fe2Al5 intermetallic that is mechanically activated. Furthermore, various aqueous solutions were evaluated by adjusting the pH with NaOH and CaO additions to increase both the rate and the amount of hydrogen generation. The Fe2Al5 intermetallic compound is useful material for the reaction with water and releases hydrogen. The results indicated that as the pH of the solution increases the amount and rate of hydrogen production increases. Reaction efficiency tends to be higher at pH = 13 with NaOH additive (near to 100%) being clearly better than CaO additive (35%). Small reaction capabilities with CaO additions are probably due to the CaO total consumption at the initial stages of the reaction, as the bayerite phase (reaction byproducts) is formed. At pH = 14, the NaOH addition reacts with iron, in addition to the reaction with aluminum particles, to achieve more than 100% reaction efficiency according to the presence of an iron oxyhydroxide phase identified by X-Ray diffraction.