Improvement of Hydrogenation and Dehydrogenation Kinetics on MgH_2 by the Catalytic Effect of ZrO_2

摘要

Hydrogen desorption temperature of MgH_2, which was milled with 20 pieces of ZrO_2 balls for 20 h, was decreased to 240°C, although steel-ball-milled MgH_2 required more than 350°C. Moreover, the completely dehydrogenated product was able to absorb hydrogen of ～3.5 mass% even at room temperature under 1 MPa hydrogen within 5 hours. Inductively coupled plasma-atomic emission spectroscopy analysis revealed zirconium element was doped into MgH_2 from the ZrO_2 balls during the milling process. Therefore, it was concluded that the presence of ZrO_2 improved the kinetics of the hydrogenation and dehydrogenation behaviors of MgH_2.