Synthesis of Magnesium Nanofibers by Electroless Reduction and their Hydrogen Interaction Properties

Magnesium (Mg) is successfully synthesized from the direct reduction of dibutylmagnesium (MgBu 2 ) with calcium (Ca). By adding 1‐dodecanethiol, the morphology of the magnesium particles is controlled and magnesium nanofibers with a length of 0.4–4 µm and a width of 40 nm are obtained. Besides magnesium nanofibers, isolated irregular shaped calcium particles are also observed as a by‐product of the reaction. The nanofibers readily absorbed hydrogen at 300 °C and hydrogen release occurred at much lower temperatures (360 °C) compared to the equivalent bulk material. More remarkably, these nanofibers remain stable during hydrogen cycling, but they partially react with the remaining calcium to form the ternary hydride phase Ca 19 Mg 8 H 54 —a phase that is usually obtained at high temperatures >500 °C and hydrogen pressure 2500 MPa. Hydrogen absorption within these magnesium nanofibers shows a slightly lower enthalpy as compared to bulk magnesium. However, the hydrogen desorption properties are influenced by the presence of calcium and its reaction with magnesium.