Detailed first-principles models of hydrogen permeation through PdCu-based ternary alloys

First-principles calculations offer a useful complement to experiments by characterizing hydrogen permeance through dense metal membranes. We report calculations that combine quantum chemistry calculations and cluster expansion methods to describe the solubility, diffusivity, and permeation of interstitial H in fcc Pd-based binary and PdCu-based ternary alloys. Specifically, we examine Pd96M4 and Pd70Cu26M4 where M = Ag, Au, Pt, Rh, Cu, Pd, and Ni. We analyze Pd-based binary alloys to demonstrate the capability of the cluster expansion approach, which we then extended to the PdCu-based ternary alloys. Our results make predictions about the properties of these alloys as membranes at moderate hydrogen pressures over the temperature range 600 ≤ T ≤ 1200 K.