Effect of element substitution on hydrogen absorption in compounds with the structure type W2CoB2

Abstract

Two new compounds, DyErNi2Al and ErLuCoNiAl, with the orthorhombic structure type W2CoB2 (Pearson symbol oI10, space group Immm) were synthesized. The intermetallics absorbed 5.2 hydrogen atoms per formula unit at room temperature under a hydrogen pressure of 570 mbar.

The hydrogenation resulted in strongly anisotropic lattice expansion, prevailing along the b-axis and accompanied by lattice contraction along the a-axis, leading to a relative volume expansion of 21.2 % for DyErNi2AlH5.2 and 17.8 % for ErLuCoNiAlH5.2. It is shown that element substitution in the positions of both f- and d-elements should be taken into account while tuning the hydrogenation properties of intermetallics.

Keywords

• Effect
• element
• substitution
• hydrogen
• absorption
• compounds
• with
• structure
• type
• W2CoB2