Hydrogen solubility in Pd3Ag phases from first-principles calculation

Abstract

First-principles calculation was used to systematically investigate hydrogen solubility in Pd3Ag phases. It was found that the solubility of hydrogen in Pd3Ag phases was much greater than in face-centered cubic (FCC) Pd, suggesting that Ag atoms enhanced hydrogen solubility with respect to FCC Pd. In addition, the present calculation also revealed that the anti-site defect formation enthalpies of Pd3Ag were close to zero, and the values of vacancy were positive and large, which indicated that Pd3Ag distributed compactly. In the process of hydrogen separation, anti-site defects decreased the hydrogen solubility in the Pd3Ag phases, i.e., the ordered Pd3Ag phases bestowed excellent properties of H selectivity. The results presented not only explore the fundamental properties of Pd3Ag phases and their various potential applications, but also agree with experimental observations reported in the literature.