title: 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 (TiO(2)) binary inverse opals with an open surface. In this method, a moisture-stable TiO(2) 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 TiO(2) binary inverse opals with a 3D-ordered macroporous (3DOM) structure. Optical reflectance spectra revealed the existence of a pseudostop band gap in the 3DOM TiO(2) 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 TiO(2) binary inverse opals without overlayers in large domains. The 3DOM TiO(2) materials were used as a photocatalyst for the degradation of benzoic acid. Results showed that in comparison to TiO(2) nanoparticles prepared under the same sintering conditions, the 3DOM TiO(2) materials displayed enhanced photocatalytic activity.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576.
authors.forename: Zhongyu
authors.initials: Z
authors.lastname: Cai
authors.forename: Jinghua
authors.initials: J
authors.lastname: Teng
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Xiong
authors.forename: Yanqiang
authors.initials: Y
authors.lastname: Li
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: Xianmao
authors.initials: X
authors.lastname: Lu
authors.forename: X S
authors.initials: XS
authors.lastname: Zhao