Effect of Pt layer on the hydrogen permeation property of La5.5W0.45Nb0.15Mo0.4O11.25-δ membrane

Catalytic Pt layers are coated on the surface of the mixed proton-electron conductive membranes based on La5.5W0.45Nb0.15Mo0.4O11.25-δ (LWNM) aiming to promote the hydrogen surface exchange, and effect of the Pt layer on the hydrogen permeation flux through the LWNM membrane has been investigated. A hydrogen permeation flux of 0.483 mL/min∙cm2 is achieved at 1000 °C fed with a mixture of 50% H2 − 50% He under wet condition with catalytic Pt layers on both sides of the LWNM membrane, which is twice as much as that of the uncoated membrane, indicating that the Pt layers on the membrane surface exhibit obvious positive effect on the hydrogen permeation. The increase of the hydrogen permeation flux is resulted from the enhancement of hydrogen dissociation/combination on the membrane surface by the Pt layer, which promotes the hydrogen surface exchange process. Moreover, it is more effective when the Pt layer is coated on the sweep side, which demonstrates that the hydrogen surface reaction on the sweep side of the membrane plays a predominant role compared with that on the feed side.