A Unique Disintegration–Reassembly Route to Mesoporous Titania Nanocrystalline Hollow Spheres with Enhanced Photocatalytic Activity.

Abstract: A novel disintegration–reassembly route is reported for the synthesis of mesoporous TiO2 nanocrystalline hollow spheres with controlled crystallinity and enhanced photocatalytic activity. In this unique synthesis strategy, it is demonstrated that sol–gel‐derived mesoporous TiO2 colloidal spheres can be disintegrated into discrete small nanoparticles that are uniformly embedded in the polymer (polystyrene, PS) matrix by surface‐induced photocatalytic polymerization. Subsequent reassembly of these TiO2 nanoparticles can be induced by an annealing process after further coating of a resorcinol–formaldehyde (RF) resin, which forms self‐supported hollow spheres of TiO2 at the PS/RF interface. The abundant phenolic groups on the RF resin serve as anchoring sites for the TiO2 nanoparticles, thus enable the reassembly of the TiO2 nanoparticles and prevent their sintering during the thermal crystallization process. This unique disintegration–reassembly process leads to the formation of self‐supported TiO2 hollow spheres with relatively large surface area, high crystallinity, and superior photocatalytic activity in dye degradation under UV light irradiation. [ABSTRACT FROM AUTHOR]