Synthesis of macroporous ZrO₂-Al₂O₃ mixed oxides with mesoporous walls, using polystyrene spheres as template

Macroporous ZrO₂-Al₂O₃ mixed oxides with mesoporous walls were synthesized. The three-dimensional interconnected macroporous structures, of inorganic zirconia-alumina mixed oxides containing different alumina compositions (25, 50, 100 wt%), were prepared by sol-gel method from inorganic precursors and using polystyrene microspheres with diameters of 685 and 1520 nm as templates. The final porous arrays with controllable pore size in the submicrometer range could be obtained by calcination of the organic template. The structural characteristics are discussed. The physicochemical characterization of the samples was carried out by N₂ physisorption (S_BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The shrinkage of pore diameter was approximately 35%, and the wall thickness of inorganic framework varied between 135 and 154 nm. The specific surface areas, of the samples, were between 123 and 287 m²/g, obtaining the largest surface area with the highest alumina contents and the smallest templates.