Hydrogen Permeability through Surface-Modified Pd76Ag14Au10 Membranes

t—Palladium-containing membranes are used for hydrogen separation and purification. However, for sufficiently thin membranes permeation flux can be limited by the kinetics of surface processes. In the present study, in order to overcome the limitation of transition through the surface, the developed Pd76Ag14Au10 alloy membranes were modified with a nanostructured surface layer. The modification was carried out by the deposition of penta-branched bimetallic Pd–Pt nanoparticles on the membrane surface. An increase in hydrogen flux was observed in a wide temperature range (25–400°C). The highest values of permeation flux density were demonstrated for membranes with a penta-branched modifier, up to 52.43 mmol s–1 m–2 at 400°С. It is assumed that the complex morphology of the nanoparticles, as well as the presence of synergistic effect from the combination of Pd and Pt, contribute to a decrease in activation barriers and an increase in catalytic activity. The developed membranes demonstrated high and stable selectivity over time, which opens up wide possibilities for their use in steam reforming reactors for producing high-purity hydrogen.