研究者詳細 - 西本　俊介

論文 - 西本　俊介

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Superhydrophobic TiO2 surfaces: Preparation, photocatalytic wettability conversion, and superhydrophobic-superhydrophilic patterning 査読

Xintong Zhang, Min Jin, Zhaoyue Liu, Donald A. Tryk, Shunsuke Nishimoto, Taketoshi Murakami, Akira Fujishima

JOURNAL OF PHYSICAL CHEMISTRY C 111 ( 39 ) 14521 - 14529 2007年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

We report herein the preparation and UV-stimulated wettability conversion of superhydrophobic TiO2 surfaces, as well as the preparation of superhydrophilic-superhydrophobic patterns by use of UV irradiation through a photomask. A CF4 plasma was used to roughen smooth TiO2 sol-gel films to produce a nanocolumnar morphology, and subsequent hydrophobic modification with octadecylphosphonic acid (ODP) rendered the roughened surfaces superhydrophobic. The superhydrophobic properties of these surfaces were evaluated by both static and dynamic water contact angle (CA) measurements. It was found that the surface morphology of the TiO2 film, which was dependent on the etching time, has a great influence on the observed superhydrophobic properties. The nanocolumnar surface morphology exhibited large water CA and small contact angle hysteresis (CAH); this is discussed in terms of the Wenzel equation and the Cassie-Baxter equation. Under low-intensity UV illumination, (1 mW cm(-2)), the superhydrophobic TiO2 surface underwent a gradual decrease of water CA and finally became superhydrophilic, due to photocatalytic decomposition of the ODP monolayer. Readsorption of ODP molecules led to the recovery of the superhydrophobic state. This UV-stimulated wettability conversion was employed to prepare superhydrophilic stripes (50 and 500 mu m wide) on a superhydrophobic TiO2 surface. The pattern was able to guide water condensation, as well as the evaporation of a polystyrene microsphere suspension, due to the extremely large wettability contrast between superhydrophobic and superhydrophilic areas.

DOI： 10.1021/jp0744432

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Anatase TiO2 nanoparticles on rutile TiO2 nanorods: A heterogeneous nanostructure via layer-by-layer assembly 査読

Zhaoyue Liu, Xintong Zhang, Shunsuke Nishimoto, Ming Jin, Donald A. Tryk, Taketoshi Murakami, Akira Fujishima

LANGMUIR 23 ( 22 ) 10916 - 10919 2007年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

We report here the use of a layer-by-layer assembly technique to prepare novel TiO2 heterogeneous nanostructures in which anatase nanoparticles are assembled on rutile nanorods. The preparation includes assembling anatase nanoparticle multilayers on rutile nanorods via electrostatic deposition using poly(sodium 4-styrene sulfonate) as a bridging or adhesion layer, followed by burning off the polymeric material via calcination. The composition of the heterogeneous nanostructures (i.e., the anatase-to-rutile ratio) can be tuned conveniently by controlling the experimental conditions of the layer-by-layer assembly. It was found that, with the optimum preparation conditions, the heterogeneous nanostructures showed better photocatalytic activity for decomposing gaseous acetaldehyde than either the original anatase nanoparticles or the rutile nanorods. This is discussed on the basis of the synergistic effect of the existence of both rutile and anatase in the heterogeneous nanostructure.

DOI： 10.1021/la7018023

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Large-scale fabrication of Ag nanoparticles in PVP nanofibres and net-like silver nanofibre films by electrospinning 査読

Ming Jin, Xintong Zhang, Shunsuke Nishimoto, Zhaoyue Liu, Donald A. Tryk, Taketoshi Murakami, Akira Fujishima

NANOTECHNOLOGY 18 ( 7 ) 2007年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IOP PUBLISHING LTD

Heat treatment of various compositions of AgNO3-doped polyvinylpyrrolidone (PVP) composite nanofibres fabricated by electrospinning produced two kinds of silver species: (i) Ag nanoparticles dispersed in PVP nanofibres, when the loading of AgNO3 was 5 wt%, and (ii) a net-like silver nanofibre film when the loading of AgNO3 was five times greater than that of PVP in the composite nanofibres. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible absorption spectroscopy, FT-IR spectra, powder x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were used to characterize the silver nanoparticles and nanofibres. The formation mechanisms are discussed based on the redox reaction between AgNO3 and PVP during heat treatment; essentially, the weight ratios of AgNO3 to PVP determined the types of morphologies, from Ag nanoparticles to silver nanofibre film. The present results may find some potential application in the design of new composite materials in the dielectric and electronics areas.

DOI： 10.1088/0957-4484/18/7/075605

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Light-stimulated composition conversion in TiO2-based nanofibers 査読

Ming Jin, Xintong Zhang, Shunsuke Nishimoto, Zhaoyue Liu, Donald A. Tryk, Alexei V. Emeline, Taketoshi Murakami, Akira Fujishima

JOURNAL OF PHYSICAL CHEMISTRY C 111 ( 2 ) 658 - 665 2007年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Silver-TiO2 nanofibers (Ag/Ti = 1/50) were fabricated by the electrospinning method, followed by heat treatment at 200 degrees C and calcination at 550 degrees C. The electrospinning solution was comprised of AgNO3 and titanium tetraisopropoxide (TTIP) with polyvinylpyrrolidone (PVP). Alternating irradiation of the silverTiO(2) nanofibers with ultraviolet and visible light can interconvert the silver species on the TiO2-based nanofibers to yield Ag metal and Ag2O, respectively, and this process has been characterized by UV-visible spectra, TEM, XRD, and XPS. The interconversion process can be rationalized in terms of the photoreduction of Ag2O by TiO2 and the oxidization of Ag by visible light. Acetaldehyde photodecomposition measurements indicate that Ag2O has better mineralization ability than Ag-0 in this kind of silver-TiO2 nanofiber photocatalytic system. The photoinduced conversion of composition on TiO2-based nanofibers may find applications in photocatalysis, antibacterial technology, and other areas.

DOI： 10.1021/jp065590n

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Neutron diffraction study on protonated and hydrated layered perovskite 査読

Shunsuke Nishimoto, Motohide Matsuda, Stefanus Harjo, Akinori Hoshikawa, Toru Ishigaki, Takashi Kamiyama, Michihiro Miyake

JOURNAL OF SOLID STATE CHEMISTRY 179 ( 11 ) 3308 - 3313 2006年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE

A layered perovskite compound with Na+, D3O+ ions (H3O+) and D2O molecules (H2O) in the interlayer, DxNa1-xLaTiO4 center dot gamma D2O, has been prepared by an ion-exchange/intercalation reaction with dilute DCl solution, using an n = 1 Ruddlesden-Popper phase, NaLaTiO4. Its structure has been analyzed in order to clarify the interlayer structure by Rietveld method, using powder neutron diffraction data. The structure analysis revealed that the layered structure changed from the space group P4/nmm-14/mmm after the ion-exchange/intercalation reaction, and it induced the transformation of perovskite layers from staggered to an eclipsed configuration. The D2O molecules and D3O+ ions loaded in the interlayer statistically occupied the sites around a body center position of rectangular space surrounded by eight apical O atoms of TiO6 octahedra in upper and lower layers. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2006.06.019

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Preparation and photocatalytic wettability conversion of TiO2-based superhydrophobic surfaces 査読

Xintong Zhang, Ming Jin, Zhaoyue Liu, Shunsuke Nishimoto, Hidenori Saito, Taketoshi Murakami, Akira Fujishima

LANGMUIR 22 ( 23 ) 9477 - 9479 2006年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

We present here a facile method for the preparation of TiO2-based superhydrophobic surfaces. It consists of two steps: (1) roughening of the TiO2 surface with a rf (radio frequency) plasma with CF4 as an etchant and (2) modification of the roughened TiO2 surface with an octadodecylphosphonic acid (ODP) monolayer. Plasma etching caused the thinning of the TiO2 film but at the same time enhanced its surface roughness. A discontinuous wedgelike surface microtexture was formed after etching for 30 s, which, after modification with a monolayer of ODP, showed Cassie-type water super-repellency with a contact angle (CA) hysteresis smaller than 2. The state of water super-repellency (water CA > 165 degrees) could be converted to the state of superhydrophilicity (water CA similar to 0 degrees) by means of ultraviolet (UV) illumination as a result of the photocatalytic decomposition of the ODP monolayer by TiO2. Readsorption of ODP molecules leads directly to the recovery of water super-repellency.

DOI： 10.1021/la0618869

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Structural change in a series of protonated layered perovskite compounds, HLnTiO(4) (Ln = La, Nd and Y) (vol 179, pg 1892, 2006) 査読

Shunsuke Nishimoto, Motohide Matsuda, Stefanus Harjo, Akinori Hoshikawa, Takashi Kamiyama, Toru Ishigaki, Michihiro Miyake

JOURNAL OF SOLID STATE CHEMISTRY 179 ( 11 ) 3590 - 3590 2006年11月

Structural change in a series of protonated layered perovskite compounds, HLnTiO(4) (Ln = La, Nd and Y) 査読

S Nishimoto, M Matsuda, S Hario, A Hoshikawa, T Kamiyama, T Ishigaki, M Miyake

JOURNAL OF SOLID STATE CHEMISTRY 179 ( 6 ) 1892 - 1897 2006年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE

A deuterated n = 1 Ruddlesclen-Popper compound, DLnTiO(4) (HLnTiO(4), Ln = La, Nd and Y), was prepared by an ion-exchange reaction of Na+ ions in NaLnTiO(4) with D+ ions, and its structure was analyzed by Rietveld method using powder neutron diffraction data. The structure analyses showed that DLaTiO4 and DNdTiO4 crystallized in the space group P4/nmm with a = 3.7232(1) and c = 12.3088(1) angstrom, and a = 3.7039(1) and c = 12.0883(1) angstrom, respectively. On the other hand, DYTiO4 crystallized in the space group P2(1)/c with a = 11.460(1), b = 5.2920(4), c = 5.3628(5) angstrom and beta = 90.441(9)degrees. The loaded protons were found to statistically occupy the sites around an apical oxygen of TiO6 octahedron in the interlayer of these compounds, rather than Na atom sites in NaLnTiO(4). (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jssc.2006.03.015

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Hydrous protonated forms derived from n=3 Dion-Jacobson-type layered perovskite titanotantalate RbLa2Ti2TaO10: Interlayer reactivity with n-alkylamine 査読

Motohide Matsuda, Toshifumi Hioki, Keisuke Okada, Shunsuke Nishimoto, Michihiro Miyake

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 67 ( 5-6 ) 1325 - 1329 2006年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

Hydrous protonated forms of layered perovskite titanotantalate were derived from the n=3 Dion-Jacobson-type RbLa2Ti2TaO10 by ion-exchange of the interlayer Rb+ ions in aqueous HNO3, and their interlayer reactivity with n-alkylamine was investigated. Although all of the protonated forms thus derived were indexed as the same tetragonal cell with P4/mmm as the host, the interlayer reactivity with n-alkylamine was degraded with an increase in the ion-exchange treatment time. A significant difference was observed in dehydration behavior below 200 degrees C. The protonated forms synthesized with short ion-exchange time showed a large endothermic peak with weight loss around 60 degrees C, while those with prolonged treatment time did not. The intercalation of n-alkylamine was confirmed for the former, but not for the latter. From these results, it was considered that hydronium ions and/or H2O Molecules responsible for the dehydration around 60 degrees C play an important role in the intercalation of n-alkylamine into the protonated forms. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpcs.2006.01.065

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Photocatalytic activities of rh-doped CaTiO3 under visible light irradiation 査読

S Nishimoto, M Matsuda, M Miyake

CHEMISTRY LETTERS 35 ( 3 ) 308 - 309 2006年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：CHEMICAL SOC JAPAN

The effect of cation substitution into CaTiO3 has been investigated. Rh-doped CaTiO3 showed intense absorption in the visible light region (lambda > 420 nm), and was found to be a new photocatalyst for H-2 evolution from ail aqueous methanol Solution under visible light irradiation.

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Structure determination of n=1 Ruddlesden-Popper compound HLaTiO<inf>4</inf> by powder neutron diffraction

Shunsuke Nishimoto, Motohide Matsuda, Stefanus Harjo, Akinori Hoshikawa, Takashi Kamiyama, Toru Ishigaki, Michihiro Miyake

Journal of the European Ceramic Society 26 725 - 729 2006年1月

A protonated n = 1 Ruddlesden-Popper compound, HLaTiO4 (DLaTiO4), has been prepared by an ion-exchange reaction of Na+ ions in NaLaTiO4 with H+ (D+) ions, and its structure has been analyzed in order to clarify the location of protons in the interlayer space, using powder neutron diffraction data. The crystal structure of DLaTiO4 belongs to the same space group, P4/nmm, as that of parent NaLaTiO4, and the D atoms were found to statistically occupy eight equivalent sites around an apical O atom of a TiO6 octahedron in the interlayer, which are different from the Na atom sites in NaLaTiO4. A comparison between DLaTiO4 and NaLaTiO4 indicated that the protonation brought the shrinkage of the interlayer space and the distortion of the TiO6 octahedron. © 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jeurceramsoc.2005.07.001

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Novel protonated and hydrated n=1 Ruddlesden-Popper phases, HxNa1-xLaTiO4 center dot yH(2)O, formed by ion-exchange/intercalation reaction 査読

S Nishimoto, M Matsuda, M Miyake

JOURNAL OF SOLID STATE CHEMISTRY 178 ( 3 ) 811 - 818 2005年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE

New derivatives of layered perovskite compounds with H3O+ ions, W ions and water molecules in the interlayer, HxNa1-xLaTiO4 (.) yH(2)O, were successfully synthesized by an ion-exchange/intercalation reaction with dilute HCl solution, using an n = 1 member of Ruddlesden-Popper phase, NaLaTiO4. Powder X-ray diffraction revealed that the layered structure changed from space group P4/nmm with a = 3.776(1) and c = 13.028(5) angstrom to I4/mmm with a = 3.7533(3) and c = 28.103(4) angstrom after the ionexchange/intercalation reaction at pH 5. The change of space group indicates that the perovskite layers are transformed from staggered to an eclipsed configuration through the ion-exchange/intercalation reaction. Thermogravimetric analysis and high-temperature powder X-ray diffraction suggested the existence of the secondary hydrated phase by dehydrating HxNa1-xLaTiO4 (.) yH(2)O at 100 degrees C. (c) 2005 Elsevier Inc. All rights reserved.

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