Phase evolution, thermodynamics and kinetics property of transition metal (TM = Zr, Ti, V) catalyzed Mg–Ce–Y–Ni hydrogen storage alloys

To improve hydrogen storage property of Mg-based alloy, the Mg–Ce–Y–Ni + 10 wt % M (M = Zr, Ti, V) composites were prepared by the combination of alloying and ball-milling, and their microstructure, phase evolution, as well as hydrogen storage thermodynamic and kinetic properties, were investigated by XRD , PCT, and DSC methods. The result shows that the hydrogenated samples are composed of MgH 2 , Mg 2 NiH 4 and corresponding ZrH 2 , TiH 2 and VH 1.9 phases. In comparison, the |Δ H| value of M = Ti sample is larger than that of M = Zr and M = V samples, and the M = Ti sample has the highest the peak temperatures and lowest plateau pressure, which indicates that Zr and V elements are more efficient to reduce the thermodynamic stability of RE-Mg-Ni hydrogen storage alloys. Besides, the DSC curve of the M = V sample has another endothermic peak which corresponds to the decomposition reaction between VH 1.9 and VH 0.8 , which has a contribution to desorption kinetic property for the M = V sample. The apparent activation energies ( E de ) show an increasing trend in the following order: M = Zr (87.7 kJ/mol) < M = V (89.1 kJ/mol) < M = Ti (99.3 kJ/mol).