Study on hydrogen generation from the hydrolysis of a ball milled aluminum/calcium hydride composite

Abstract

Metal Al was ball milled with CaH₂ to improve its hydrolysis properties. The effects of reaction temperature and milling conditions on the hydrogen generation performances of Al are investigated. A higher temperature has been shown to be beneficial for the hydrolysis of Al–CaH₂ composites. With increasing the added amount of CaH₂ and milling time, the grain size of Al is decreased and the protective oxide film on the surface of the Al powder is damaged. The hydrolysis of CaH₂ helps to open up the structure of Al grains and provide OH⁻ to enhance the corrosion of Al. As a result, the hydrogen production of Al powder has been greatly optimized, and the addition of CaH₂ proves to be more effective than the addition of some other hydrides. The yield and maximum hydrogen generation rate (mHGR) of an Al-10 mol% CaH₂ mixture milled for 15 h are 97.8% and 2074.3 mL min⁻¹ g⁻¹, respectively.