Emulsion-Templated Hierarchically Porous Silica Beads Using Silica Nanoparticles as Building Blocks

Abstract

Uniform silica beads were produced using emulsion-templated polymer beads as templates and silica nanoparticles as building blocks. Hybrid silica/alumina and silica/titania beads were also prepared by immersing silica−polymer composite beads or silica beads in the corresponding precursor solutions. Inorganic beads were produced by calcining the polymer−inorganic composites at 520 °C in air. The resulting materials exhibited a hierarchical mesoporous−macroporous structure, with high pore volumes and high surface areas. The mechanical stability of the beads could be enhanced by sintering at 1450 °C under argon or by using sodium silicate as a precursor, but with a concomitant reduction in the total surface area of the materials.