Influence of Fe@C composite catalyst on the hydrogen storage properties of Mg–Ce–Y based alloy

Abstract A composite catalyst Fe@C was successfully prepared by chemical blowing and carbonization method, at the same time its defect level, pore distribution and specific surface area were investigated. In addition, the Mg–Ce–Y + x wt.% Fe@C (x = 1, 3, 6, 10) composites also were synthesized by mechanical ball-milling. The effect of the Fe@C content on hydrogen absorption and desorption property of the Mg–Ce–Y alloy was characterized by XRD, SEM, TEM, PCI, and DSC method. The activated composites exhibit an excellent absorption and desorption kinetic performance, which attributeed to the efficient catalysis of Fe@C composite catalyst. The Mg–Ce–Y + 6 wt % Fe@C composite exhibits the fastest hydrogen absorption/desorption kinetics and relatively lower decomposition temperature and it can absorb 90% of the maximum hydrogen capacity within 2 min and only takes 12 min to release the same amount of hydrogen under 300 °C. Besides, the dehydrogenation activation energy is reduced to 84.9 kJ/mol and the initial hydrogen release temperature is less than 250 °C, which is owing to the outstanding synergistic catalyst effect of Fe@C on Mg-based hydrogen storage alloy. However, the thermodynamic properties of the composites have not been improved, of which the enthalpy change is 80.6 kJ/mol.