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 Al65Cu20Fe15 on de/rehydrogenation properties of magnesium hydride (MgH2). Catalyzed through this catalyst, the onset desorption temperature of MgH2 gets reduced significantly from similar to 345 degrees C (for ball-milled MgH2) to similar to 215 degrees 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 degrees C. Improved rehydrogenation kinetics has been found even at lower temperatures of 200 and 150 degrees C by absorbing similar to 5.50 and similar to 5.40 wt % of H-2, respectively, within 1 min and similar to 5.00 wt % at 100 degrees C in 30 min. These are some of the lowest desorption temperatures and rehydrogenation kinetics obtained for MgH2 through any other known catalyst. The storage capacity of MgH2 catalyzed with the leached version of Al65Cu20Fe15 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.