title: Unprecedentedly enhanced solar photocatalytic activity of a layered titanate simply integrated with TiO2nanoparticles.
abstract: We report a simple, low-cost methodology for unprecedentedly enhancing the photocatalytic activity of layered inorganic semiconductors. A layered titanate with a lepidocrocite-type structure scarcely showed photocatalytic activity for a test reaction, the oxidative decomposition of formic acid in water into CO2, under simulated solar light, but it showed highly enhanced photocatalytic activity upon mixing with a much smaller amount (approximately 10 wt%) of commercially available TiO2nanoparticles (P25) in water. The photocatalytic activity of the mixture was approximately 5 times that of P25, a benchmark photocatalyst. From various analyses, the enhancement resulted from the transfer of photoexcited electrons from the layered titanate to P25 at their particle interfaces and retardation of charge recombination. When applied to a photocatalyst for H2production from water containing methanol under simulated solar light, the layered titanate/P25 mixture showed considerably enhanced activity and the apparent quantum yield was 23% (at 320 nm). By replacing P25 with Pt co-catalyst-loaded P25, the apparent quantum yield of the mixture increased from 23 to 73%, although an extremely small amount (below 0.06%) of Pt was used in the system.
authors.affiliation: Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan and Department of Earth Sciences, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Earth Sciences, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Kozeni
authors.affiliation: Department of Earth Sciences, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Sohmiya
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Komaguchi
authors.affiliation: Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan and Department of Earth Sciences, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ogawa
authors.affiliation: Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan and Department of Applied Chemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan and Kagami Memorial Research Institute for Material Science and Technology, Waseda University, 2-8-26 Nishiwaseda, Shinjuku-ku, Tokyo 169-0054, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Sugahara
authors.affiliation: Graduate School of Creative Science and Engineering, Waseda University, 1-6-1 Nishiwaseda, Shinjuku-ku, Tokyo 169-8050, Japan and International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki Tsukuba, Ibaraki, 305-0044, Japan. IDE.Yusuke@nims.go.jp.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ide