Thermal stability of Vale Inco nanonometric nickel as a catalytic additive for magnesium hydride (MgH2)

摘要: Abstract The structure stability of nanometric-Ni (n-Ni) produced by Vale Inco Ltd. Canada as a catalytic additive for MgH2 has been investigated. Each n-Ni filament is composed nearly spherical interconnected particles having mean diameter 42 ± 16 nm. After ball milling the MgH2 + 5 wt.%n-Ni mixture 15 min are found to be uniformly embedded within and at their surfaces. Neither during nor its first decomposition temperatures 300, 325, 350 375 °C elemental reacts with Mg form Mg2Ni intermetallic phase (and eventually Mg2NiH4 hydride). acts strong catalyst accelerating kinetics desorption. From Arrhenius Johnson–Mehl–Avrami–Kolmogorov theory activation energy desorption determined ∼94 kJ/mol. cycling 300 °C ∼99 kJ/mol. This much lower than ∼160 kJ/mol observed undoped milled MgH2. During 275 converted into (Mg2NiH4). newly formed nanosized grain on order 20 nm. Its potency seems similar precursor. formation (Mg2NiH4) may one factors responsible systematic decrease hydrogen capacity upon 300 °C.