Curious Catalytic Characteristics of Al–Cu–Fe Quasicrystal for De/Rehydrogenation of MgH₂

The present study reports the curious catalytic action of a new class of catalyst, quasicrystal of Al 65 Cu 20 Fe 15 on de/rehydrogenation properties of magnesium hydride (MgH 2 ). Catalyzed through this catalyst, the onset desorption temperature of MgH 2 gets reduced significantly from ∼345 °C (for ball-milled MgH 2 ) to ∼215 °C. A more dramatic effect of the above catalyst has been observed on rehydrogenation. Here, 6.00 wt % of hydrogen storage capacity is observed in just 30 s at 250 °C. Improved rehydrogenation kinetics has been found even at lower temperatures of 200 and 150 °C by absorbing ∼5.50 and ∼5.40 wt % of H 2, respectively, within 1 min and ∼5.00 wt % at 100 °C in 30 min. These are some of the lowest desorption temperatures and rehydrogenation kinetics obtained for MgH 2 through any other known catalyst. The storage capacity of MgH 2 catalyzed with the leached version of Al 65 Cu 20 Fe 15 quasicrystalline alloy degrades negligibly even after 51 cycles of de/rehydrogenation. The feasible reason for catalytic action has been described and discussed on the basis of structural, microstructural, Fourier transform infrared, and X-ray photoelectron spectroscopic studies.