Formation of three-dimensional ordered hierarchically porous metal oxides via a hybridized epoxide assisted/colloidal crystal templating approach.

Three-dimensionally ordered hierarchically porous alumina, iron(III) oxide, yttria, and nickel oxide have been prepared through the hybridization of colloidal crystal-templating and a modified sol–gel method. Simply, highly ordered arrays of poly(methyl methacrylate) (PMMA) were infiltrated with a precursor solution of metal salt and epoxide. Calcination after solidification of the material removed the polymer template while forming the inverse replicas, simultaneously. These hierarchical structures possessing macropore windows and mesopore walls were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and N2 adsorption/desorption techniques to probe the structural integrity. It was revealed by PXRD that the prepared 3D frameworks were single-phase polycrystalline structures with grain sizes between 5 and 27 nm. The thermal stability as studied by TGA illustrates expected weight losses and full decomposition of the PMMA template. SEM reve...