Controlled one-step synthesis of hierarchically structured macroscopic silica spheres

Novel hierarchically structured macroscopic silica spheres have been synthesized using a biphasic oil-in-water system. The spheres are prepared in a one-step process by injection of the precursor solution into water. This leads to controlled hydrolysis and condensation of the silanes. The precursor solution contained three different silanes, a block copolymer acting as surfactant and a solvent. The spheres have a hierarchically layered morphology, high mechanical stability, specific surface areas up to 700 m2/g with mesopores in the range of 9–27 nm. The synthesis of such materials with a simultaneous control of the macroscopic and microscopic structure allows facile implementation in separation and catalysis.

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► One-step emulsion based synthesis of millimeter-sized silica spheres.
► Hierarchical core-shell morphology.
► Controlled macro- and mesopores via specific surfactant molecules.