Effect of Different Sizes of Nano CuO Catalysts on Hydrogen Storage Properties of Mg2Ni Based Composites

Nanosized CuO particles were synthesized via precipitation method, and the crystalline sizes were controlled by adjusting different calcinations temperature. XRD result shows that the obtained samples exhibit CuO single phase structure, the crystalline sizes are 7.5, 14.4nm and 23.4nm respectively. Then Mg2Ni-Ni-5%CuO composites were obtained through ball milling technique, the electrochemical hydrogen storage properties, kinetic performances and the activation energies of hydrogen desorption were tested and analyzed. The results show that the maximum discharge capacities and the electrocatalytic activity on the surface and the diffusivities of H in the bulk of the Mg-based composites electrodes are improved by adding the nanosized CuO catalysts. DSC measurement shows that the nanosized CuO catalyst leads to decrease in hydrogen desorption temperature by about 50K than that of composites without CuO. The activation energies of the composites of Mg2Ni-Ni and Mg2Ni-Ni -5% CuO600,which are calculated by Kissinger formula, are 86.9kJ/mol and 89.3kJ/mol respectively.