A durable Pd-based
alloy is used for a H2-selective membrane in a
hydrogen generator, as in the fuel processor of a fuel
cell plant. The Pd-based
alloy includes Cu as a binary element, and further includes “X”, where “X” comprises at least one
metal from group “M” that is BCC and acts to stabilize the β BCC phase for stability during operating temperatures. The
metal from group “M” is selected from the group consisting of Fe, Cr, Nb, Ta, V, Mo, and W, with Nb and Ta being most preferred. “X” may further comprise at least one
metal from a group “N” that is non-BCC, preferably FCC, that enhances other properties of the membrane, such as
ductility. The metal from group “N” is selected from the group consisting of Ag, Au, Re, Ru, Rh, Y, Ce, Ni, Ir, Pt, Co, La and In. The at. % of Pd in the binary Pd—Cu
alloy ranges from about 35 at. % to about 55 at. %, and the at. % of “X” in the higher order alloy, based on said
binary alloy, is in the range of about 1 at. % to about 15 at. %. The metals are selected according to a novel process.