Pyrolysis and combustion characteristics of aluminum hydride coated with an oxide layer and stearic acid

To explore the mechanism of the hydrogen storage materials by coating, the pyrolysis and combustion characteristics of aluminum hydride (AlH3) coated with an oxide layer (Al2O3) and stearic acid (C18H36O2) through reaction molecular dynamics and dust minimum ignition temperature experiments are investigated. The minimum ignition temperature of 335 °C for AlH3/C18H36O2 dust cloud is obtained with a mass concentration of 500 g/m3. In the initial stage of pyrolysis and combustion of AlH3, the structure of the AlH3 nanoparticle becomes irregular and the H-Al bond breaks rapidly. Due to the existence of the coating layers, the release of H atoms should first pass through the coating layers, resulting in the reduction of the reaction rate. H2 and H2O are produced after the release of H atoms, as the main final products in pyrolysis and combustion, respectively. C2H4 is the main intermediate product because of the coating of C18H36O2. The remaining atoms of C, O, and Al combine to form Al-C-O clusters, and C-Al bonds show an increasing trend during the pyrolysis and combustion, indicating the formation of clusters. The results are expected to provide basic data support for the safe application of AlH3.