A practical technique for the fabrication of highly ordered macroporous structures of inorganic oxides

Well-defined macroporous ceramics consisting of SiO2, TiO2 and ZrO2 have been fabricated via a template-assisted colloidal processing technique. Close-packed polymer spheres were first prepared as a template using centrifugation or gravitational sedimentation, followed by infiltration with alkoxide precursors. The centrifugation should be preferred because it is a less time-consuming process and the materials are better ordered. The removal of the template beads was achieved by calcination of the organic–inorganic hybrids at appropriate temperatures, yielding well-ordered macroporous ceramics. The arrangement of the porous structures could be changing the preparation of the packed polymer templates. Some novel arrangements of macropores were obtained in these macroporous ceramics: a simple square-packed arrangement for SiO2, the coexistence of hexagonal close-packed and simple close-packed arrangements for TiO2, and face-centered cubic packed arrangement for ZrO2. The resulting highly structured ceramics could have applications in areas ranging from quantum electronics to photocatalysis and battery materials.