Effects of the post-synthesis treatment on the structural properties of alumina-doped zirconia

Zirconia doped by 5 wt% alumina was prepared by sol–gel processing of aluminum sec-butoxide and zirconium butoxide in the presence of acetic acid and a surfactant (Pluronic P123) as organic additives. The influence of different post-synthesis treatment methods, i.e., supercritical drying with CO2, aging in the mother liquor at 100°C or solvothermal treatment in ethanol or ethanol/water, on the textural properties of the mixed-oxide gels was investigated after calcination at 500°C. Solvothermal treatment or aging at elevated temperatures resulted in crystalline primary particles with diameters in the range 2–6 nm, while only partially crystalline particles (10–15 nm) were obtained by supercritical drying. The texture of the powders and the aluminum environment were rather independent of the kind of post-synthesis treatment. Solvothermal treatment resulted in significantly higher surface areas and pore volumes.