Study of hydrogen storage in Mg2Ni by thermal desorption spectrometry

The hydrogen storage properties of Mg2Ni have been investigated using thermal desorption spectrometry (TDS). After charging the pulverized Mg2Ni with hydrogen, the TDS spectrum was measured in situ from room temperature to 703 K. Such a hydrogen absorption-desorption cycle was repeated several times. A desorption peak was observed at about 515 K which increases during the first few cycles but then decreases beyond the sixth cycle. It was found that the peak shifts to 465 K and the hydrogen storage capacity is increased when the absorption is performed in an atmosphere containing 2 vol.% oxygen. The effect is explained in terms of metallic Ni segregation at the alloy surface.