Improvement of hydrogen absorption rate of Pd by ion irradiation

Palladium (Pd) is used for the purification of H2 gas and as a catalyst for the dissociation of H2 molecules. Since low energy ion irradiation is quite useful for surface modification of materials, the hydrogen absorption properties of Pd is expected to be improved by ion irradiation. In this work, we aimed at investigating the effect of ion irradiation on the hydrogen absorption rate of Pd. Ion irradiation was made with H+, He+ and Ar+ in an acceleration energy range from 30 to 350 keV up to a dose of 1×1017/cm2. As a result, the ion irradiated Pd sample was found to induce a higher absorption rate than that of the unirradiated one. The initial hydrogen absorption rate was also found to increase with increasing irradiation energy. These results conclude that defects introduced in Pd by ion irradiation facilitate the rate of nucleation and growth of hydride.