Synthesis of mesoporous zirconia with crystalline framework in super-critical ethanol

By using nonionic polyethylene oxide surface (PEO) as a template, mesoporou s zirconia was synthesized in super-critical ethanol under different condit ions(wide pH, various types of PEO and different chelates). XRD, N-2 adsorp tion-desorption isotherm, TEM and selected area electron diffraction confir med that the as-synthesized powder was mesoporous zirconia with tetragonal walls. Similar to MSU silica, mesoporous zirconia showed single XRD in smal l angle, spongy-like pore arrangement and nonmonotonic relation between the pore size and the surfactant length. Thus, the: analogous assembly mechani sm most likely took place for PEO as the template by forming micelles in th ermal ethanol, BET surface area and pore size could be modified by varying PEG, pH and chelate. The as-synthesized mesoporous zirconia had;poor therma l stability. It might be because the calcination caused further crystalliza tion and the deformation of crystalline framework, thus losing the meaoporo us structure. It is well known that some oxides such as SiO2, Al2O3 or TiO2 can effectively stabilize tetragonal zirconia. Therefore, incorporation wi th SiO2, Al2O3 or TiO2, the meso-structure of zirconia successfully retaine d on the calcination at 673 K, or even up to 723 K in some cases. The relat ed work will be published later.