(544b) Heterogeneous Mixtures of Boron Compounds with Metals and Water for Hydrogen Generation

Sodium borohydride (SBH) and ammonia borane (AB) are promising hydrogen-storing compounds to feed fuel cells for portable electronic devices. To release hydrogen from these compounds, pyrotechnic mixtures of SBH and AB with solid oxidizers were considered by previous researchers. Alternatively, Hydrolysis of these compounds has also been studied extensively. To obtain high hydrogen yield without any adverse environmental effects, we use heterogeneous mixtures of SBH or AB with gelled water and nanoaluminum or magnesium. Due to the highly exothermic metal-water reaction, such mixtures, upon ignition, exhibit self-sustained propagation of combustion wave with simultaneous release of hydrogen from the boron compounds and water. Mechanistic studies of this process were conducted using digital video recording, pressure monitoring, thermocouple measurements, gas chromatography, mass spectrometry, TGA, and powder XRD analysis. Isotopic tests using D2O were performed to characterize roles of thermolysis and hydrolysis.