Fabrication of TiO2 Binary Inverse Opals without Overlayers via the Sandwich-Vacuum Infiltration of Precursor

Abstract

A sandwich-vacuum method was demonstrated for the fabrication of titania (TiO2) binary inverse opals with an open surface. In this method, a moisture-stable TiO2 precursor was backfilled into the interstitial spaces of polystyrene binary colloidal crystals (PS bCCs), which served as a template. Removal of the template by calcination yielded TiO2 binary inverse opals with a 3D-ordered macroporous (3DOM) structure. Optical reflectance spectra revealed the existence of a pseudostop band gap in the 3DOM TiO2 samples. The position of the pseudostop band gap shifted to the low-wavelength region as the number ratio of small over large PS spheres was increased in the template. The sandwich-vacuum method proved to be simple and rapid for the fabrication of TiO2 binary inverse opals without overlayers in large domains. The 3DOM TiO2 materials were used as a photocatalyst for the degradation of benzoic acid. Results showed that in comparison to TiO2 nanoparticles prepared under the same sintering conditions, the 3DOM TiO2 materials displayed enhanced photocatalytic activity.No Full Tex