| A wet impregnation technique based on the evaporation-crystallisation method was used to prepare mono- and bi-metallic catalytic membranes, using Al2O3 or TiO2 multilayer porous tubes with a top-layer pore size of 5, 10, 25, 30 or 100 nm. The metal deposition was characterized by weight uptakes, chemical analyses, SEM-EDS and XPS analyses. In all tubes with a mesoporous top-layer bearing pores of 5, 10 or 25 nm, whatever the nature of the tube and the impregnation solvent (water or acetone), a strong metal enrichment was evidenced in the top-layer. This enrichment was less noticeable in tubes with a 30 or 100 nm top-layer pore size. A mathematical model describing the metal salts deposition during the drying step is proposed. This model is discussed in relation with the physical parameters involved in the drying of complex porous systems. |
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