Metallic Glassy V45Zr20Ni20Cu10Al3Pd2 Alloy Powders for Superior Hydrogenation/Dehydrogenation Kinetics of MgH2

Abstract

Nanocrystalline MgH2 powders with an average grain size of 7 nm in diameter were synthesized via reactive ball milling (RBM) approach, using a high energy ball mill operated under a high hydrogen pressure of 50 bar. The as-synthesized MgH2 powders obtained after 200 h of RBM showed slow hydrogenation/dehydrogenation kinetics. In order to improve the kinetics behaviors of this binary metal hydride system, multicomponent-metallic glassy V45Zr20Ni20Cu10Al3Pd2 alloy powders fabricated by mechanical alloying under liquid nitrogen were used as a heterogeneous catalytic agent. For the purpose of the present study, the MgH2 powders were doped with 10 wt.% of the metallic glassy powders and ball-milled for 50 h. The results have shown that the decomposition temperature of as-doped MgH2 with 10 wt.% of V45Zr20Ni20Cu10Al3Pd2 powders was 308.9 °C, being far below than that one measured for pure MgH2 (416 °C). This new nanocomposite system possessed outstanding properties, indexed by the fast kinetics of absorption and desorption of 5.5 wt.% H2 within 200 s at a rather low temperature (180 °C).