Preparation and characterization of mesoporous ceria-zirconia-alumina nanocomposite with high hydrothermal stability

CeO₂-ZrO₂-γ-Al₂O₃ mixed oxides with different molar compositions have been synthesized by the sol-gel method using nitrate-alkoxide precursors. Some relationships between the molar composition of the ternary systems and their textural and structural properties are presented. CeO₂-ZrO₂ -γ-Al₂O₃ mixed oxides have been studied and characterized using x-ray diffraction, transmission electron microscopy, and Raman spectroscopic analyses. By complete porosity analyses of all samples before and after hydrothermal (up to 75% steam) treatment at 500 °C, we have been able to optimize a highly hydrothermally stable CeO₂-ZrO₂-γ-Al₂O₃ system with a molar ratio of 10:10:80 mol%. γ-Al₂O₃ alone and CeO₂-doped as well as ZrO₂-doped γ-Al₂O₃ were also investigated by the hydrothermal treatment, and their steam-sensitive properties have been compared with those of the ternary CeO₂-ZrO₂ -γ-Al₂O₃ system.