H2 desorption from and thermal cycling of a Pd95Ag5/Al2O3 composite membrane

The permeation behavior of a 2.0 μm thick Pd95Ag5/ceramic composite membrane was investigated. The membrane exhibited a good stability during 20 temperature cycles between 473 K and 673 K in H2 atmosphere and 3 additional cycles down to room temperature in N2, resulting only in a slight increase of the N2 leak rate at 673 K. H2 desorption experiments showed that between 5 h at 673 K and 9 h at 523 K were required for a complete release of H2 from the composite membrane. Analysis of the released H2 volumes showed that the release was largely limited by the mass transport resistance of the porous ceramic support.