豊島 遼 (トヨシマ リョウ)

Toyoshima, Ryo

写真a

所属(所属キャンパス)

理工学部 化学科 (矢上)

職名

助教

 

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  • XPS and HAXPES analyses for pre-sputtered InP surface and InP/Pt interface

    Saito Y., Uemura S., Kagiyama T., Toyoshima R.

    Japanese Journal of Applied Physics (Japanese Journal of Applied Physics)  61 ( 3 )  2022年03月

    ISSN  00214922

     概要を見る

    The state of the pre-sputtered indium phosphide (InP) surface was analyzed by X-ray photoelectron spectroscopy, employing synchrotron-based relatively low-energy X-ray. It was found that the pre-sputtering treatment induced the phosphorus vaporization and made the surface composition In-rich, which was thought to promote oxidation of InP surface in atmosphere. The state of the interface between InP and Pt was also investigated nondestructively, by using hard X-ray photoemission spectroscopy. As a result, it was demonstrated that the interfacial layer was composed of the native oxide (In-O, P-O) and metallic state (In-Pt or In-In, P-P) and that the pre-sputtering treatment increased significantly the amount of the P-O, In-Pt or In-In, and P-P. From a simplified calculation, assuming a Pt/In-Pt/In-P layer stacking structure and neglecting the In-O and P-O components, the thickness of the interfacial layer was estimated to be approximately 3.0 nm.

  • A newly designed compact CEY-XAFS cell in the soft X-ray region and its application to surface XAFS measurements under ambient-pressure conditions without photoinduced side effects

    Shimizu H., Toyoshima R., Isegawa K., Mase K., Nakamura J., Kondoh H.

    Physical Chemistry Chemical Physics (Physical Chemistry Chemical Physics)  24 ( 5 ) 2988 - 2996 2022年02月

    ISSN  14639076

     概要を見る

    We report a newly designed compact cell to measure XAFS spectra with the conversion electron yield (CEY) method in the soft X-ray region under ambient-pressure gas conditions. Secondary electrons generated from the gas and sample by collision of X-ray-absorption-induced Auger electrons are collected by a positively biased collector electrode to obtain XAFS spectra. It was confirmed that this cell is applicable to soft X-ray surface XAFS measurements for different types of materials such as insulating organic materials and metal oxides under 1 bar gas conditions. During the measurements, photoinduced side effects were observed; i.e. photoinduced degradation of organic materials and photoinduced reduction/oxidation of metal oxides. We found that these photoinduced side effects can be sufficiently suppressed by controlling the measuring conditions. The presented measuring approach will enable surface XAFS spectra to be obtained in the soft X-ray region for various types of functional materials under ambient-pressure working conditions. This journal is

  • Ligand effects on surface oxide at RhPd(100) alloy surfaces: A density functional theory calculation study

    Shirahata N., Toyoshima R., Yoshida M., Ueda K., Mase K., Mun B.S., Kondoh H.

    Surface Science (Surface Science)  716 2022年02月

    ISSN  00396028

     概要を見る

    Density functional theory calculations were applied to a study on ligand effects on a Pd surface oxide formed on RhPd(100) alloy surfaces. It was found that chemical composition of the topmost layer of alloy significantly influences on the electronic structure of the Pd surface oxide. Such interlayer ligand effects are originating from the Rh−O and Pd−O interactions between the topmost layer of alloy and the Pd surface oxide. These effects give rise to substantial changes in binding energies of adsorbates and could change catalytic activity depending on atomic fraction of the Rh−Pd alloy.

  • Materials Science Research by Ambient Pressure X-Ray Photoelectron Spectroscopy Systems at Synchrotron Radiation Facilities in Japan: Applications in Energy, Catalysis, and Sensors

    Yamamoto S., Takagi Y., Koitaya T., Toyoshima R., Horio M., Matsuda I., Kondoh H., Yokoyama T., Yoshinobu J.

    Synchrotron Radiation News (Synchrotron Radiation News)  2022年

    ISSN  08940886

  • In situ AP-XPS study on reduction of oxidized Rh catalysts under CO exposure and catalytic reaction conditions

    Toyoshima R., Ueda K., Koda Y., Kodama H., Sumida H., Mase K., Kondoh H.

    Journal of Physics D: Applied Physics (Journal of Physics D: Applied Physics)  54 ( 20 )  2021年05月

    ISSN  00223727

     概要を見る

    Reduction of oxidized Rh catalysts under carbon monoxide (CO) exposure and reaction conditions were studied by using ambient-pressure x-ray photoelectron spectroscopy. First, Rh powders pressed into a pellet were deeply oxidized and the reduction process under 100 mTorr CO environment was monitored in situ at different temperatures. The oxidized Rh surfaces are composed of Rh2O3 and RhO2, the latter of which is more segregated near the surface. Both oxide species are reduced simultaneously to the metallic state; kinetic analyses indicate that the activation energy of the reduction of the Rh oxides is 1.68 eV, which is a little larger than those for Pd oxides, probably due to a stronger Rh-O interaction. Reduction of oxidized Rh nano-particles deposited on SiO2 under two reaction conditions (CO + O2 and CO + NO + O2) was observed with increasing temperature. It was found that the reduction temperature shifts to the higher temperature in the presence of NO, even though the S-factors are almost the same. The NO molecule more strongly prevents the reduction of oxidized Rh catalyst compared to O2.

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担当授業科目 【 表示 / 非表示

  • 自然科学実験

    2022年度

  • 化学実験第1

    2022年度

  • 自然科学実験

    2021年度

  • 化学実験第1

    2021年度

  • 自然科学実験

    2020年度

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