Hydrolysis of hydrided Mg-3Ni-2MnO ₂ composites prepared by ball milling for hydrogen production

95% Mg+3% Ni+2%MnO ₂ (Mg-3Ni-2MnO ₂) composite powders were milled under hydrogen atmosphere by high-energy planetary ball mill for 100 h, and characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the hydrolysis kinetics of the composites were investigated. It showed that the Mg-3Ni-2MnO ₂ could be fully hydrogenated and the Mg formed MgH ₂ completely. The measured particle sizes are in the range of 0.1~5 μm, while their grain sizes are in the range of 1~40 nm estimated theoretically. The desorption volume of hydrogen could be increased by increasing the reaction temperature. The hydrogen up to 91.3% of desorption capacity of the composites is released within 20 min from the hydrogenated composites in the second deionized water at 343 K. It promises to be a new technology of hydrogen sources with safety and high efficiency. The Avrami index values change stage suggested that the reaction mechanisms for the hydrided Mg-3Ni-2MnO ₂ composite powders were different in different temperature through the process of reaction with water.