LAUSR

In this work, Mg2Ni(Fe)H4 was synthesized using precursors of nano Ni(Fe) composite powder prepared through arc plasma method and coarse-grained Mg powder. The microstructure, composition, phase components and the hydrogen storage properties of the Mg–Ni(Fe) composite were carefully investigated. It is observed that the Mg2Ni(Fe)H4 particles formed from the Mg–Ni(Fe) composite have a diameter of 100–240 nm and a portion of Fe in the Ni(Fe) nano particles transformed into α-Fe nano particles with the diameter of 40–120 nm. DSC measurements showed that the peak desorption temperature of the Mg2Ni(Fe)H4 was reduced to 501 K and the apparent activation energy for hydrogen desorption of the Mg2Ni(Fe)H4 was 97.2 kJ mol−1 H2. The formation enthalpy of Mg2Ni(Fe)H4 was measured to be −53.1 kJ mol−1 H2. The improvements in hydrogen sorption kinetics and thermodynamics can be attributed to the catalytic effect from α-Fe nano particles and the destabilization of Mg2NiH4 caused by the partial substitution of Ni by Fe, respectively.