title: The Critical Effect of Niobium Doping on the Formation of Mesostructured TiO2 : Single-Crystalline Ordered Mesoporous Nb-TiO2 and Plate-like Nb-TiO2 with Ordered Mesoscale Dimples.
abstract: Highly ordered mesoporous niobium-doped TiO2 with a single-crystalline framework was prepared by using silica colloidal crystals with ca. 30 nm in diameter as templates. The preparation of colloidal crystals composed of uniform silica nanoparticles is a key to obtain highly ordered mesoporous Nb-doped TiO2 . The XPS measurements of Nb-doped TiO2 showed the presence of Nb(5+) and correspondingly Ti(3+) . With the increase in the amount of doped Nb, the crystalline phase of the product was converted from rutile into anatase, and the lattice spacings of both rutile and anatase phases increased. Surprisingly, the increase in the amount of Nb led to the formation of plate-like TiO2 with dimpled surfaces on one side, which was directly replicated from the surfaces of the colloidal silica crystals.
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kitahara
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shimasaki
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Matsuno
authors.affiliation: Waseda Institute for Advanced Study, Nishiwaseda-1, Shinjuku-ku, Tokyo 169-8050 (Japan).
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kuroda
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shimojima
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Wada
authors.affiliation: Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199. kuroda@waseda.jp.|Kagami Memorial Research Institute for Materials Science and Technology, Nishiwaseda-2, Shinjuku-ku, Tokyo 169-0051 (Japan). kuroda@waseda.jp.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kuroda
keywords: niobium; oxides; porosity; template synthesis; titanium