Hydriding/dehydriding properties of NdMgNi alloy with catalyst CeO2

Hydrogen storage composites Nd2Mg17-50 wt.%Ni-x wt.%CeO2(x=0, 0.5, 1.0, 1.5, 2.0) were obtained by induction-ball milling method. The catalytic effect of CeO_2 on hydriding kinetics of Nd_2Mg17-50 wt.%Ni composite was investigated. X-ray diffraction(XRD) and high resolution transmission electron microscopy(HRTEM), selected area electron diffraction(SAED) analyses showed that Nd_2Mg17-50 wt.%Ni alloy had a multiphase structure, consisting of NdMg12, NdMg_2Ni, Mg_2Ni and Ni phases and the addition of catalyst CeO_2 prompted the composites to be partly transformed into amorphous strucutre. The CeO_2 improved the maximum hydrogen capacity of Nd_2Mg17-50 wt.%Ni alloy from 3.192 wt.% to 3.376 wt.%(x=1.0). What's more, the increment of diffusion coefficient D led to the faster hydriding kinetics, which was calculated by Avrami-Erofeev equation. The dehydrogenation temperature reduced from 515.54 to 504.72 K was mainly caused by the decrease of activation energy from 93.28 to 69.36 kJ /mol, which was proved by the Kissinger equation.