Recursos de colección

Hokkaido University Collection of Scholarly and Academic Papers (136.044 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

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Mostrando recursos 161 - 171 de 171

  1. Fabrication and photoelectrochemical property of tungsten(VI) oxide films with a flake-wall structure

    Amano, Fumiaki; Li, Ding; Ohtani, Bunsho
    Efficient visible light-induced photoelectrochemical oxidation of water was achieved using a tungsten(IV) oxide (WO3) film composed of perpendicularly oriented plate-like crystallites, a flake-wall film, prepared on a transparent conductive substrate by controlling anisotropic crystal growth of tungsten oxide hydrate (WO3・H2O) followed by calcination.

  2. 非線形振動分光法によるリン脂質二分子膜の構造評価

    叶, 深

  3. Visible-light-induced photocatalysis through surface plasmon excitation of gold on titania surfaces

    Kowalska, Ewa; Mahaney, Orlando Omar Prieto; Abe, Ryu; Ohtani, Bunsho
    Fifteen commercial titania (titanium(IV) oxide; TiO2) powders were modified with gold by photodeposition to prepare photocatalysts that work under irradiation with light in the visible range (vis). The gold-modified titania (Au/TiO2) powders were characterized by diffuse reflectance spectroscopy (DRS), field-emission scanning electron microscopy (FE-SEM), scanning transmission microscopy (STEM) and X-ray powder diffraction analysis (XRD). It was shown that all tested powders could absorb visible light with an absorption maximum at localized surface plasmon resonance (LSPR) wavelengths (530-600 nm) and that the size and shape of gold nanoparticles determined absorption ranges. The photocatalytic activity of Au/TiO2 powders was examined both under...

  4. Action spectrum analyses of photoinduced superhydrophilicity of titania thin films on glass plates

    Yan, X.; Abe, R.; Ohno, T.; Toyofuku, M.; Ohtani, B.
    Samples of titania-thin-film-coated glass plates were prepared by spin coating of commercial titania-coating liquids using a home-made spin coater (1000 rpm, 30 s) and then calcined in air at 673 K for 2 h. In a part of experiments, samples were stored in an oven at 393 K overnight. A piece of sample was set in a 10-mm rectangular quartz cell, and monochromatic light (FWHM of ca. 17 nm, intensity of ca. 10^[8] einstein s^[-1]) was irradiated in ambient air using a grating multiple-wavelength photoirradiation instrument (Jasco CRM-FD). Water contact angle (WCA) of samples before and after monochromatic irradiation was...

  5. Two step water splitting into H2 and O2 under visible light by ATaO2N (A=Ca, Sr, Ba) and WO3 with IO3-/I- shuttle redox mediator

    Higashi, Masanobu; Abe, Ryu; Teramura, Kentaro; Takata, Tsuyoshi; Ohtani, Bunsho; Domen, Kazunari
    Two-step water splitting into H2 and O2 under visible light irradiation is examined combining Pt-ATaO2N (A=Ca, Sr, Ba) as a H2 evolution photocatalyst and Pt-WO3 as an O2 evolution photocatalyst by IO3-/I- shuttle redox-mediator. Overall water splitting proceeds when Pt-CaTaO2N or Pt-BaTaO2N is used for H2 evolution photocatalyst, whereas photo-induced self-oxidative decomposition is predominant for Pt-SrTaO2N. The onset wavelengths of H2 evolution almost accord with the absorption edges of CaTaO2N and BaTaO2N. The available wavelength of light for H2 evolution in the present two-step water splitting system has been extended to 660 nm by using BaTaO2N.

  6. 表面増強赤外分光でみた電極-電解液界面の水の構造と挙動

    大澤, 雅俊; 山方, 啓
    水は電極-電解液界面でどう振る舞うであろうか? これは電気化学で最も基本的でかつ重要な研究課題の一つである.Helmholtzによる1853年の電気二重層の提案から始まった電極界面構造の研究は, 1960年代になって, 水は界面の電場に沿って配列し, 電位(表面電荷)によってその配向を変化させる, という現在一般的に受け入れられているモデルに到達した.しかし, これを直接確認する手段がなく, 詳細は永年不明のままであった.最近の計算化学と電極界面のその場測定方法の進展により, 電極界面を分子レベルでより詳細に検討することが可能になり, 新しい知見が得られるようになってきている.本稿では, 表面増強赤外分光(SEIRAS)による解析を中心として, 最近の進展の一端を紹介する.

  7. What is Degussa (Evonik) P25? Crystalline composition analysis, reconstruction from isolated pure particles and photocatalytic activity test

    Ohtani, B.; Prieto-Mahaney, O. O.; Li, D.; Abe, R.
    Anatase and rutile crystallites were isolated from Degussa (Evonik) P25 by selective dissolution with a hydrogen peroxide-ammonia mixture and diluted hydrofluoric acid, respectively, and used as standard samples for calibration curves of X-ray diffraction analyses. The results showed that P25 contains more than 70% anatase with a minor amount of rutile and a small amount of amorphous phase. The composition anatase/rutile/amorphous could be determined by analysis of P25 mixed with an internal standard, nickel(II) oxide. However, it was also found that the composition of P25 used in this study was inhomogeneous and changed depending on the position of sampling from...

  8. Efficient and selective epoxidation of styrene with TBHP catalyzed by Au25 clusters on hydroxyapatite

    Liu, Yongmei; Tsunoyama, Hironori; Akita, Tomoki; Tsukuda, Tatsuya
    Au25 clusters supported on hydroxyapatite oxidized styrene in toluene with 100% conversion and 92% selectivity to the epoxide, under optimum conditions and using anhydrous tert-butyl hydroperoxide (TBHP) as an oxidant.

  9. Nanowire-structured titanate with anatase titania : Characterization and photocatalytic activity

    Amano, Fumiaki; Yasumoto, Taikei; Shibayama, Tamaki; Uchida, Satoshi; Ohtani, Bunsho
    Nanowire-structured titanate with titanium(IV) oxide (titania) was obtained by calcination of potassium ion-containing titanate nanowires prepared through alkali treatment of titania nanoparticles. The presence of potassium ions in the as-synthesized titanate nanowires was required for maintenance of the nanowire structure under the conditions of post heat treatment. The crystallite structure, composition, morphology, specific surface area, pore volume distribution, and optical properties were found to be dependent on the temperature at which titanate nanowires were calcined. Photocatalytic activity was examined using three probe reactions: oxidative decomposition of acetic acid in an aqueous solution, oxygen liberation from an aqueous silver sulfate solution,...

  10. Two-directional N2 desorption in thermal dissociation of N2O on Rh(110), Ir(110), and Pd(110) at low temperatures

    Horino, H.; Rzez'nicka, I.; Kokalj, A.; Kobal, I.; Ohno, Y.; Hiratsuka, A.; Matsushima, T.
    Two-directional N2 desorption was found in N2O dissociation on Rh(110), Ir(110), and Pd(110) below 160 K by angle-resolved thermal desorption. N2O(a) is mostly dissociated during heating procedures, emitting N2(g) and leaving O(a). N2 showed four desorption peaks in the temperature range of 110–200 K. One of them commonly showed a cosine distribution, whereas the others sharply collimated off the surface normal in the plane along the [001] direction. The collimation angle was about 70° on Rh(110), 65° on Ir(110), and 43°–50° on Pd(110). A high-energy-atom assisted desorption model was proposed for N2 inclined emission.

  11. CO2 desorption dynamics on specified sites and surface phase transitions of Pt(110) in steady-state CO oxidation

    Rzez'nicka, Izabela; Moula, Md. Goula; de la Garza, Leonard Morales; Ohno, Yuichi; Matsushima, Tatsuo
    The spatial and velocity distributions of desorbing product CO2 were studied in the steady-state CO oxidation on Pt(110) by cross-correlation time-of-flight techniques. The surface structure transformation was monitored by LEED in the course of the catalyzed reaction. In the active region, where the surface was highly reconstructed into the missing-row form, CO2 desorption split into two directional lobes collimated along 25° from the surface normal in the plane including the [001] direction, indicating the CO2 formation on inclined (111) terraces. The translational temperature was maximized at the collimation angle, reaching about 1900 K. On the other hand, CO2 desorption sharply...

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