No abstract

No abstract

Summary Catalytic effects of TiH2 on hydrogenation/dehydrogenation kinetics of MgH2 were investigated in this study. The TG analysis showed that the addition of the x wt% TiH2 exhibited lower onset temperature of 160°C which is 100°C and 190°C lower than as‐milled and as‐received MgH2. The dehydrogenation and hydrogenation kinetics were significantly improved compared with the pure MgH2. The activation energy for the hydrogen desorption of MgH2 was reduced from −137.13 to −77.58 kJ/mol by the addition of TiH2. XRD and XPS results showed that the phase of TiH2 remained same during the dehydrogenation without any intermediate formation confirming its role as catalyst.

Composite formation with Zr-based Laves phase alloys, especially the ZrCr 2 family, is an effective method to improve the hydriding properties of MgH 2 . The present paper describes a systematic study of the reaction pathway of Mg−x wt % ZrCrCu composites (x = 25, 50) in terms of their structural, morphological, and hydrogenation properties. XRD and SEM results show no interaction between Mg and the ZrCrCu alloy phase during composite preparation by high-energy ball-milling. However, hydriding/annealing cycles lead to the formation of the Mg 2 Cu phase at grain boundaries of the Mg−ZrCrCu matrix. This Mg 2 Cu phase does not interact with the hydrogen at the studied condition, but provides several diffusion paths and stable nucleation sites for the formation of MgH 2 , and thus enhances the sorption kinetics. Pressure composition temperature (PCT) analysis shows a reduction in desorption temperature down to 250 °C for these composites.