Effect of Cu catalyst on the hydrogenation and thermodynamic properties of Mg2Ni

Hydrogenation performance of Mg2Ni can be improved by introducing nano-crystalline microstructures into the bulk and the modifications of surface through catalysts as well. The challenge with solid state catalysts is to be dispersed on the surface homogeneously. If the dispersion is not homogeneous somehow, it could be compensated by increasing the amount of catalyst, but at the cost of storage capacity. The use of catalyst fasten the sorption process and vanish the need of long activation process even after the exposure of powder sample to air. Ball milling is one of the efficient method to introduce both of the above effects together. The present work describe the effect of Cu catalyst in varying amount (Cu = 0, 2, 5, 10 wt%) on the crystallographic, morphologic and hydrogen sorption behavior of Mg2Ni including the thermodynamic aspects. Effect of Cu is found to be positive in terms of forming comparatively unstable hydrides. Hydrogen storage capacity and enthalpy of formation of Mg2Ni with 10 wt% Cu reduces to 1.81 wt% and 26.69 KJ (mol H)−1 from 3.56 wt% and 54.24 KJ (mol H)−1 for pure Mg2Ni at 300 °C respectively.

► The effect of Cu on the crystallographic, morphologic and hydrogen sorption behavior of Mg2Ni has been studied.
► Cu is found to have positive effect in forming comparatively unstable hydrides.
► Hydrogen storage capacity and enthalpy of formation of Mg2Ni with 10 wt% Cu is found to be 1.81 wt% and 26.69 KJ (mol H)−1 respectively.
► Formation of unstable hydrides is compensated by the decrement in hydrogen storage capacity.