Effect of a Pt-ZrO₂ protection layer on the performance and morphology of Pd-Au alloy membrane during H₂S exposure

We prepared a disc-type Pd-Au alloy membrane, on which a Pt-ZrO₂ protection layer was deposited to protect the hydrogen membrane from H₂S poisoning. The effect of the protection layer on the performance and morphology of the Pd-Au alloy membrane during H₂S exposure was investigated. The hydrogen flux did not decrease significantly in the presence of the protection layer, which covered the surface of the membrane. When the membrane with the protection layer was exposed to a mixture of H₂S, the hydrogen flux decreased to 35% of the original value, which is half of the decrease observed with the bare Pd-Au membrane. The hydrogen flux of the poisoned membrane was almost completely recovered after changing back to pure H₂ gas. Under harsh conditions, the membrane with the protection layer was found to retain the hydrogen flux and selectivity, while the selectivity of the bare membrane decreased to zero, indicating that it was disintegrated. This means that the Pt-ZrO₂ layer prevents direct contact between Pd and H₂S, thus protecting the Pd membrane from poisoning.