Highly ordered porous zirconias from surfactant-controlled syntheses: Zirconium oxide-sulfate and zirconium oxo phosphate

The syntheses and characterization of mesostructured hexagonally ordered su rfactant composites using zirconium sulfate ions as inorganic precursor spe cies are described. On the basis of the mesostructured zirconium sulfate su rfactant composites, two porous MCM-41 analogues have been synthesized: zir conium oxide-sulfate and zirconium oxo phosphate. For the zirconium oxo pho sphates, a special postsynthetic treatment has been developed. The pore arr angements and wall structures were characterized by XRD, nitrogen adsorptio n, EXAFS, and TEM. The porous zirconia based materials show hexagonal arran gements of uniformly sized pores and amorphous pore walls. Both zirconium o xide-sulfate and zirconium oxo phosphate show remarkable thermal stability up to 500 degrees C. Therefore, the surfactant has been completely removed from the structures by calcination. So far, this is the highest thermal sta bility compared to other porous transition metal oxides prepared via surfac tant-controlled synthesis.