Characterization of zirconia modified porous stainless steel supports for Pd membranes

Author： Gao Huiyuan Li Yongdan Lin Jerry Zhang Baoquan

ISSN： 1380-2224

Source： Journal of Porous Materials, Vol.13, Iss.3, 2006-08, pp. : 419-426

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Abstract

A thin well-bonded zirconia film was formed on a porous stainless steel support by a sol-gel dip-coating method followed by firing in hydrogen atmosphere. The zirconia layer has a cubic phase structure. The surface composition of the film was analyzed by X-ray photoelectron spectroscopy. A comparison between H₂-fired and air-fired samples indicated that the surface/interface composition of the sample fired in air was rich in Fe₂O₃, whereas that of the fired in H₂ contained more metastable cubic zirconia phase and spinel type iron chromate. Binding energy shifts of Zr and Fe in the mixed oxides, together with the presence of iron and chromium oxides suggests that interfacial reaction between the coating and the substrate occurred, which is favorable for a good adhesion of the layers. The average pore size of the support modified by multilayer zirconia coatings declined drastically from original 2 μm to the coated top-layer 0.4 μm. The ZrO₂ film showed a hydrogen selectivity of 2.7 for H₂/N₂, and a hydrogen flux of 1.159 × 10⁻³ mol/m².s at room temperature and with a pressure difference of 101 kPa across the film.