A novel strategy for the preparation of supported PdAu alloy layers allows the facile and fast fabrication of highly permeable and selective H-2 separation membranes from refractory metals via electroless plating and low-temperature alloying. Homogenous alloying of multiple, separately deposited Pd and Au layers with thickness in the nm range required less than one week at 773 K under atmospheric H-2 as evidenced by X-ray diffraction and H-2 permeation measurements. The H-2 permeation rate IN, became stable within a day even, reaching 0.62 mol m(-2) s(-1) at 773 K and Delta P-H2 = 100 kPa. The corresponding N-2 leak rate remained constant during a 350 h experiment, resulting in an ideal H-2/N-2 selectivity of 1400 and demonstrating that such membranes tolerate extended operation at that temperature well. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.