Rapid hydrogen generation from Al-Si alloy and recovery of the byproducts

The metal hydrolysis reaction is a convenient and user-friendly strategy for obtaining high-purity hydrogen on- demand. However, removal of the oxide and rapid corrosion of the metal are critical for hydrogen utilization in fuel cell. In this work, commercial Al-Si alloy, which is widely used in metal casting, are used as a raw material to generate high-purity hydrogen. Our results indicate that hydrogen evolution and Al corrosion are influenced by NaOH concentration, elevated temperature from exothermic reaction of Al or Si with OH-, decreased particle size of Al and the Al/Si micro-galvanic cell. And the maximum hydrogen generation rate is 116.4 mL (0.4 g)-1 min- 1 for Al-10Si. This reaction consumes OH- ions from NaOH following addition of the first two batches, and then OH- ions derived from Al(OH)-4 or Al(OH)3.The hydrogen generated is transferred to a fuel cell; a stable current of ca. 1 A and voltage of about 0.25 V are obtained for Al-10Si during continuous hydrogen input. The by-product of pure Al(OH)3 and Si can be recovered separately. This investigation of Al-Si alloys as hydrogen generation materials may provide guidance for the exploration of other Si-based materials.