Experimental Study on the Relationship Between Unit Cell Parameters and Dehydrogenation Temperature of β-MgH2

To reveal the relationship between the crystal structure and the hydrogen desorption activity of MgH2, magnesium-based materials doped with anthracite, molybdenum disulfide, and cobalt were prepared by mechanical ball milling. The relationship between the cell parameters of beta-MgH2 and the corresponding dehydrogenation peak temperature was investigated by x-ray diffraction and temperature-programmed desorption. The results show that the unit cell lattice constant a of beta-MgH2 is the most critical parameter to determine the dehydrogenation temperature with a negative correlation. With identical material composition, a larger a value leads to a lower dehydrogenation temperature of beta-MgH2. The catalytic effect of the three substances on beta-MgH2 hydrogen desorption is in the order of Co > anthracite > MoS2. The initial temperature of beta-MgH2 hydrogen desorption by cobalt doping is as low as 175 C.

Automated summary

This study reveals the relationship between the crystal structure and the hydrogen desorption activity of MgH2. The unit cell lattice constant a of beta-MgH2 is found to be the critical parameter determining the dehydrogenation temperature, with a negative correlation. Cobalt is found to have the best catalytic effect on beta-MgH2, with the lowest initial temperature of hydrogen desorption.