Figure 4 (a) and (b) show the XRD p

Figure 4 (a) and (b) show the XRD patterns of dehydrogenated ZK60 with 5wt%CNTs and 5wt%graphe+2ml cyclohexane, respectively. The XRD patterns for other additives are similar, hence are omitted here. The strong and sharp peaks indicate that the crystallinity of the powder has been maintained after hydrogenation. All samples with CNTs exhibit similar XRD patterns after dehydrogenation at different absorption/desorption temperature, as shown in Figure 4 (a). There is no residue hydride present, which indicates the asorbed hydrogen has been released completely. Figure 4b shows that both magnesium and magnesium hydroxide are present in the sample containing 5wt% graphene+2ml cyclohexane. It is speculated that the effect of activation conditions on the complete reduction of alloy oxide layer is not as good as that of the additive. The research shows that the activation at high temperature can effectively reduce the oxide layer on the surface of magnesium alloy. The formation of oxide and hydroxide layer on the alloy surface greatly reduces the hydrogen absorption capacity. The same is true for other organic additives and hydrogenation conditions.