Hollow Silica Spheres with a Novel Mesoporous Shell Perforated Vertically by Hexagonally Arrayed Cylindrical Nanochannels

Hollow silica spheres with a mesoporous shell perforated by hexagonally arrayed cylindrical nanochannels have been synthesized using one-pot sol-gel/emulsion approach. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) investigations reveal that the shells of the as-made hollow silica spheres are partially covered by amorphous silica particles, which can be eliminated to a great extent after an additional hydrothermal treatment in autoclave. The hollow core structure is most likely formed by the stable benzene-in-water emulsion which acts as the removable template. And surfactant P123 favors the assembly of silica to form the mesostructured shell under acidic conditions. Using these hollow silica spheres as the hard template, structurally stable hollow carbon can be obtained, indicating that the pores on the silica shell are interconnected.