(699a) Palladium Membranes on Mesoporous Ceramic Supports: Effect of Metal-Support Interface on Hydrogen Permeation

Thin palladium membranes are synthesized on mesoporous ã-alumina/á-alumina and yttria stabilized zirconia (YSZ)/á-alumina composite supports by sputter deposition and electroless plating method. The effect of metal-substrate interaction on H2 permeation was investigated by comparing H2 fluxes through the Pd/γ-alumina/α-alumina and Pd/YSZ/α-alumina supprots in 633-713K. H2 fluxes through Pd/γ-alumina/α-alumina are lower than those through Pd/YSZ/α-alumina membrane of the same thickness under the same conditions. The permeation data are analyzed by a model considering hydrogen diffusion in the bulk of the Pd layer and surface reaction at the metal-support interface. The Pd-alumina interface provides much higher surface reaction resistance for hydrogen permeation than the Pd-zirconia interface due to formation of Pd-Al alloy at the Pd-alumina interface. The results show the importance of the selection of a chemically inert material as the support for thin metal membranes.