title: In Situ Fluorine Doping of TiO2 Superstructures for Efficient Visible-Light Driven Hydrogen Generation.
abstract: With the aid of breakthroughs in nanoscience and nanotechnology, it is imperative to develop metal oxide semiconductors through visible light-driven hydrogen generation. In this study, TiOF2 was incorporated as an n-type F-dopant source to TiO2 mesocrystals (TMCs) with visible-light absorption during the topotactic transformation. The crystal growth, structural change, and dynamic morphological evolution, from the initial intermediate NH4 TiOF3 to HTiOF3, TiOF2, and F-doped TMCs, were verified through in situ temperature-dependent techniques to elucidate the doping mechanism from intermediate TiOF2. The visible-light efficiencies of photocatalytic hydrogen were dependent on the contents of the dopant as compared with the pure TMC and a controled reference. Using femtosecond time-resolved diffuse reflectance spectroscopy, the charge-transfer dynamics were monitored to confirm the improvement of charge separation after doping.
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Graduate School of Science, Kobe University. tachikawa@port.kobe-u.ac.jp.|PRESTO (Japan) Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan. tachikawa@port.kobe-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tachikawa
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Fujitsuka
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan. majima@sanken.osaka-u.ac.jp.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Majima
mesh_terms: D005461:Fluorine / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008027:Light; D046529:Microscopy, Electron, Transmission; D013056:Spectrophotometry, Ultraviolet; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D005461:Fluorine; D006859:Hydrogen; D014025:Titanium
keywords: charge-transfer; hydrogen generation; photocatalyst; titania; topotactic transformation