LAUSR

Abstract Molecular dynamics simulations on the reactions of nano-aluminum, water with different proportions of hydrogen peroxide were performed by ReaxFF. The reaction rate of the system increases by 27% as the molar ratio of H2O2 increases from 0 to 30%. The reaction paths in each period are elucidated by the change of the numbers of reactants and products. The reaction absorbs heat and releases isolated H atoms in the initial stage through pathways Al + 3H2O → Al(OH)3 + 3H and 3Al + 2H2O → 2AlO + AlH3 + H. Subsequently, H2O2 decomposes and releases O2 through 2H2O2 → 2H2O + O2 as the temperature rises to 350 K. And these O2 are rapidly involved in the formation of Al2O3, corresponding to the process 4AlO + O2 → 2Al2O3 and 2Al(OH)3 + 2AlH3 + 3O2 → 2Al2O3 + 6H2O. In the final stage, H2 molecules generated in accordance with the pathways of Al(OH)3 + AlH3 → Al2O3 + 3H2 and 2AlH3 + 3H2O → Al2O3 + 6H2. Particularly, the production of H2 decreases by 28.2%, 49.8% and 68.6%, as the molar ratio of H2O2 increases from 0 to 10%, 20% and 30%, respectively. Meanwhile, the reaction of Al/H2O/H2O2 releases much more energy (271.40–440.53 kJ/mol) than that of Al/H2O (180.67 kJ/mol). Moreover, the ignition temperature decreases with the increase of H2O2 concentration, but is proportional to the heating rate of ignition. When the molar ratio of H2O2 increases from 0 to 30%, the adiabatic flame temperature of the mixture increases linearly from 2400 K to 3000 K according to the adiabatic simulation.