Hydrogen storage properties of Mg-Ni-Cu prepared by hydriding combustion synthesis and mechanical milling (HCS + MM)

The effect of Cu-doping on the hydrogen storage properties of Mg₉₅Ni₅Cu_x (x = 0, 0.5, 1, 2) prepared by hydriding combustion synthesis and mechanical milling (HCS + MM) was studied. For dehydriding properties, the dehydriding temperature onset decreases from 450 K for Mg₉₅Ni₅ to 420 K for Mg₉₅Ni₅Cu₂. Additionally, the activation energy for dehydriding decreases from 116 kJ/mol for Mg₉₅Ni₅ to 98 kJ/mol for Mg₉₅Ni₅Cu₂, indicating that the dehydriding reaction is activated by the catalytic effect of Cu. Moreover, the hydrogen absorption capacity of Mg₉₅Ni₅Cu₂ at 373 K in 100 s increases from 0.95 to 4.16 wt.% by MM pretreatment before HCS. The factors for the improvement of the hydrogen storage properties are discussed in this paper.