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Investigation of hydrogen superoxide adsorption during ORR on Pt/C catalyst in acidic solution for PEFC by ${it in-situ}$ high energy resolution XAFS

山本 直生*; 松村 大樹; 萩原 悠人*; 田中 啓偉*; 長谷川 優太*; 石井 賢司*; 田中 裕久*

Journal of Power Sources, 557, p.232508_1 - 232508_10, 2023/02

Oxygen Reduction Reaction (ORR) is one of the key electrochemical reactions, especially in Polymer Electrolyte Fuel Cells (PEFCs). In this work, the reaction pathway and intermediate species such as molecular-type oxygen during ORR were discussed. High energy resolution X-ray absorption fine structure spectra at the Pt L$$_{3}$$-edge were obtained to observe the electronic structure of Pt catalyst. Carbon-supported Pt nanoparticles as powder catalysts were used for measurement as more realistic conditions, and the species adsorbed on the Pt nanoparticles were analyzed while controlling under the potentials in acidic electrolyte solution with N$$_{2}$$ or O$$_{2}$$ gas bubbling. Molecular-type oxygen adsorption species is observed only in the O$$_{2}$$-bubbled electrolyte solution. This intermediate adsorption species is assigned to a hydrogen superoxide.


Development of evaluation method for core deformation reactivity in sodium-cooled fast reactor; Verification of core deformation reactivity evaluation based on first-order perturbation theory

堂田 哲広; 加藤 慎也; 飯田 将来*; 横山 賢治; 田中 正暁

Proceedings of 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS12) (Internet), 8 Pages, 2022/10



Development of ARKADIA-Design for design optimization support; Application of coupling method using multi-level simulation technique for plant thermal-hydraulics analysis

堂田 哲広; 吉村 一夫; 浜瀬 枝里菜; 横山 賢治; 上羽 智之; 田中 正暁

Proceedings of Technical Meeting on State-of-the-art Thermal Hydraulics of Fast Reactors (Internet), 3 Pages, 2022/09




田中 正暁; 堂田 哲広; 横山 賢治; 森 健郎; 岡島 智史; 橋立 竜太; 矢田 浩基; 大木 繁夫; 宮崎 真之; 高屋 茂

第26回動力・エネルギー技術シンポジウム講演論文集(インターネット), 5 Pages, 2022/07



Development of numerical analysis codes for multi-level and multi-physics approaches in an advanced reactor design study

田中 正暁; 堂田 哲広; 森 健郎; 横山 賢治; 上羽 智之; 岡島 智史; 松下 健太郎; 橋立 竜太; 矢田 浩基

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03



Development of evaluation method for core deformation reactivity feedback in sodium-cooled fast reactor by coupled analysis approach

堂田 哲広; 上羽 智之; 横山 賢治; 根本 俊行*; 田中 正暁

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 14 Pages, 2022/03



Magnons and spinons in Ba$$_{2}$$CoTeO$$_{6}$$; A Composite system of isolated spin-$$frac{1}{2}$$ triangular Heisenberg-like and frustrated honeycomb Ising-like antiferromagnets

児島 佑樹*; 栗田 伸之*; 田中 秀数*; 中島 健次

Physical Review B, 105(2), p.L020408_1 - L020408_6, 2022/01

 被引用回数:2 パーセンタイル:66.83(Materials Science, Multidisciplinary)



High spatial resolution neutron transmission imaging using a superconducting two-dimensional detector

宍戸 寛明*; 西村 和真*; Vu, TheDang*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; et al.

IEEE Transactions on Applied Superconductivity, 31(9), p.2400505_1 - 2400505_5, 2021/12

 被引用回数:0 パーセンタイル:0(Engineering, Electrical & Electronic)

中性子イメージングは、重金属に対する高透過性、軽元素に対する高感度、同位体と中性子との特異な核反応による同位体選択性などの中性子ビームの特徴を活かした非破壊検査の有力な手段の一つである。本研究では、超伝導検出器である電流バイアス運動インダクタンス検出器(CB-KID)を用いて、パルス中性子源を用いた飛行時間法による波長分解中性子イメージングを行った。遅延時間型CB-KIDを用いて、GdAl$$_{3}$$単結晶を成長させたGd-Al合金試料の中性子透過像を取得した。その結果、単結晶はAl-Gd合金全体に渡って、形状,分布ともに良好に観察することができた。また、中性子の波長0.03nm以上でGdによる特徴的な中性子の吸収を確認した。さらに、15$$mu$$m$$ times$$ 12$$mu$$mという限られた検出面で、同位体と中性子の核反応によって生じる$$^{155}$$Gd共鳴ディップを観測することができた。また、$$^{155}$$Gdの共鳴ディップを用いてGd選択的イメージングを行ったところ、中性子の波長幅が1pmという限られた範囲で、明確なGd核の元素選択イメージング像を取得することに成功した。


Fe, Mn and $$^{238}$$U accumulations in ${it Phragmites australis}$ naturally growing at the mill tailings pond; Iron plaque formation possibly related to root-endophytic bacteria producing siderophores

中本 幸弘*; 土山 紘平*; 春間 俊克*; Lu, X.*; 田中 万也; 香西 直文; 福山 賢仁; 福嶋 繁; 小原 義之; 山路 恵子*

Minerals (Internet), 11(12), p.1337_1 - 1337_17, 2021/12

 被引用回数:1 パーセンタイル:0.02(Geochemistry & Geophysics)

坑水は、重金属の含有や低pHのため、世界中で鉱業の重要な水問題となっている。水生植物による「rhizofiltration」は、根系に重金属を蓄積することにより水中の重金属を除去する効果的な浄化方法のひとつである。ヨシは根の周囲に鉄プラークを形成して重金属を蓄積することから「rhizofiltration」に使用できる候補植物とされる。本研究調査地である人形峠ウラン鉱山の鉱さいたい積場には1998年からヨシが自然に繁茂している。本研究の結果から、ヨシはFe, Mn, Uを高濃度で節根に蓄積しており、また鉄プラークを形成する節根にもこれらの元素が高濃度蓄積していることが明らかになった。さらにヨシの節根から分離した細菌837株のうち88.6%にシデロフォア産生能が確認された。細菌のシデロフォアにはカテコール基を有するものが多く報告されているが、Feとカテコールあるいはフェノール性化合物の錯体はネットワークを形成することにより沈殿することが知られている。そこで本研究では、ヨシの根周囲の鉄プラーク形成に微生物の産生するシデロフォアが影響するという仮説を立てた。内生細菌${it Pseudomonas}$ spp.や${it Rhizobium}$ spp.の代謝産物にFeイオンを加えたところ沈殿が確認され、これらの細菌の代謝産物としてフェノール性化合物が検出された。以上より、ヨシの根から分離した内生細菌${it Pseudomonas}$ spp.及び${it Rhizobium}$ spp.が産生するシデロフォアはFeと沈殿することで、鉄プラーク形成に影響している可能性が考えられた。また、鉄プラークは植物体外の金属蓄積部位としてヨシの重金属耐性に関与すると考えられることから、内生細菌${it Pseudomonas}$ spp.と${it Rhizobium}$ spp.が間接的にヨシの耐性に貢献している可能性が考えられた。


Hybridization of Bogoliubov quasiparticles between adjacent CuO$$_2$$ layers in the triple-layer cuprate Bi$$_2$$Sr$$_2$$Ca$$_2$$Cu$$_3$$O$$_{10+delta}$$ studied by angle-resolved photoemission spectroscopy

出田 真一郎*; Johnston, S.*; 吉田 鉄平*; 田中 清尚*; 森 道康; 安齋 太陽*; 井野 明洋*; 有田 将司*; 生天目 博文*; 谷口 雅樹*; et al.

Physical Review Letters, 127(21), p.217004_1 - 217004_6, 2021/11

 被引用回数:0 パーセンタイル:0(Physics, Multidisciplinary)

Hybridization of Bogoliubov quasiparticles (BQPs) between the CuO$$_2$$ layers in the triple-layer cuprate high-temperature superconductor Bi$$_2$$Sr$$_2$$Ca$$_2$$Cu$$_3$$O$$_{10+delta}$$ is studied by angle-resolved photoemission spectroscopy (ARPES). In the superconducting state, an anti-crossing gap opens between the outer- and inner-BQP bands, which we attribute primarily to interlayer single-particle hopping with possible contributions from interlayer Cooper pairing. We find that the $$d$$-wave superconducting gap of both BQP bands smoothly develops with momentum without abrupt jump in contrast to a previous ARPES study. Hybridization between the BQPs also gradually increases in going from the off-nodal to the anti-nodal region, which is explained by the momentum-dependence of the interlayer single-particle hopping. As possible mechanisms for the enhancement of the superconducting transition temperature, the hybridization between the BQPs, as well as the combination of phonon modes of the triple CuO$$_2$$ layers and spin fluctuations are discussed.


Practical tests of neutron transmission imaging with a superconducting kinetic-inductance sensor

Vu, TheDang; 宍戸 寛明*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; 宮嶋 茂之*; et al.

Nuclear Instruments and Methods in Physics Research A, 1006, p.165411_1 - 165411_8, 2021/08

 被引用回数:0 パーセンタイル:0.02(Instruments & Instrumentation)

We found that the sizes of the Gd islands determined from the transmission image correlated strongly with those determined from the SEM image. We demonstrated the CB-KID could be used to identify (1) tiny voids in a thermally sprayed continuous Gd$$_2$$O$$_3$$ film in and (2) various mosaic morphologies and different eutectic microstructures in Wood's metal samples. The fact that the CB-KID system could be used to identify features of samples with a wide distribution of sizes and thicknesses is promising for real application of the device for imaging samples of interest to material scientists. Operating the CB-KID at higher temperatures appreciably improved the efficiency for simultaneously identifying the X and Y positions of hotspots. We also compared the detection efficiency with the PHITS simulations. We now plan to improve the detection efficiency by increasing the thickness of the $$^{10}$$B neutron conversion layer


Observation of adsorbed hydrogen species on supported metal catalysts by inelastic neutron scattering

吉田 寿雄*; 山本 旭*; 細川 三郎*; 山添 誠司*; 吉川 聡一*; 原 賢二*; 中村 充孝; 蒲沢 和也*; 田中 庸裕*

Topics in Catalysis, 64(9-12), p.660 - 671, 2021/08

 被引用回数:2 パーセンタイル:9.63(Chemistry, Applied)

Inelastic neutron scattering (INS) enables direct and selective observation of H species due to the extremely large incoherent neutron scattering cross section of a hydrogen atom. In the present study, the adsorbed H species on some heterogeneous precious metal catalysts supported by alumina and carbon black were investigated by in situ INS spectroscopy with a newly designed sample cell. Three alumina-supported metal catalysts having Pt, Pd, and Rh metal nanoparticles with different particle sizes exhibited different INS spectra in intensities and band distribution. Observation of the H species on the metal nanoparticles and the alumina surface revealed their properties. In addition, the H atoms stored in Pd nanoparticles were observed as palladium hydride. In contrast, the H species on a Pt catalyst supported by carbon black were found to be strongly adsorbed on the carbon support.



堂田 哲広; 上羽 智之; 根本 俊行*; 横山 賢治; 田中 正暁

計算工学講演会論文集(CD-ROM), 26, 4 Pages, 2021/05



Identification of hydrogen species on Pt/Al$$_{2}$$O$$_{3}$$ by ${it in situ}$ inelastic neutron scattering and their reactivity with ethylene

山添 誠司*; 山本 旭*; 細川 三郎*; 福田 良一*; 原 賢二*; 中村 充孝; 蒲沢 和也*; 佃 達哉*; 吉田 寿雄*; 田中 庸裕*

Catalysis Science & Technology, 11(1), p.116 - 123, 2021/01

 被引用回数:4 パーセンタイル:36.19(Chemistry, Physical)

Hydrogen (H) species adsorbed on catalyst surfaces are key intermediates in catalytic hydrogenation reactions over supported metal catalysts. However, individual identification of H species on the metal catalysts has not been established to date. Here, we elucidated the H species on Pt/Al$$_{2}$$O$$_{3}$$ by the combination of ${it in situ}$ inelastic neutron scattering (INS) and density functional theory (DFT). Several H species in the presence of H$$_{2}$$ were successfully identified at different sites on the Pt surface and Al$$_{2}$$O$$_{3}$$ support. The ${it in situ}$ INS and FT-IR measurements revealed that the hydride/atop Pt-H, bridged perimeter/terrace Pt-H-Pt, and threefold Pt$$_{3}$$-H are active intermediates in the C$$_{2}$$H$$_{4}$$ hydrogenation reaction, whereas the edge Pt-H-Pt is a rather inert species. In addition, the ${it in situ}$ measurements indicate that the Al$$_{2}$$O$$_{3}$$ itself acts as hydrogen storage material by mediating AlO-H and Al-H-Al species, which serve H species in the C$$_{2}$$H$$_{4}$$ hydrogenation reaction.


Formation of $$alpha$$ clusters in dilute neutron-rich matter

田中 純貴*; Yang, Z.*; Typel, S.*; 足立 智*; Bai, S.*; Van Beek, P.*; Beaumel, D.*; 藤川 祐輝*; Han, J.*; Heil, S.*; et al.

Science, 371(6526), p.260 - 264, 2021/01

 被引用回数:25 パーセンタイル:98.55(Multidisciplinary Sciences)



Homogeneity of neutron transmission imaging over a large sensitive area with a four-channel superconducting detector

Vu, TheDang; 宍戸 寛明*; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 宮嶋 茂之*; 奥 隆之; 曽山 和彦; 相澤 一也; et al.

Superconductor Science and Technology, 34(1), p.015010_1 - 015010_10, 2021/01

 被引用回数:3 パーセンタイル:42.13(Physics, Applied)

We demonstrated that a four-readout superconducting neutron imaging system shows good spatial heterogeneity and linearity using the delay-line method. We examined the precise pattern of a $$^{10}$$B-dot-array absorber and found the X-direction pitch (Px) = 250.7 um with a scatter of (Hx)= 5.4 um and the Y-direction pitch (Py)= 249.1 um with a scatter of (Hy)= 3.4 um while the $$^{10}$$B dot array was fully extended toward the X direction across the detector sensitive area. We consider that this demonstrates detection with good spatial homogeneity and conclude. The transmission-imaging system is suitable for use at pulsed neutron facilities. We also reported a clear transmission image of tiny screws and nuts, and ladybug (insect). We recognize that further efforts to improve the detection efficiency are necessary to make using the detector more practical.



堂田 哲広; 浜瀬 枝里菜; 横山 賢治; 田中 正暁

計算工学講演会論文集(CD-ROM), 25, 4 Pages, 2020/06



Localized magnetic excitations in the fully frustrated dimerized magnet Ba$$_{2}$$CoSi$$_{2}$$O$$_{6}$$Cl$$_{2}$$

栗田 伸之*; 山本 大輔*; 金坂 拓哉*; 古川 信夫*; 河村 聖子; 中島 健次; 田中 秀数*

Physical Review Letters, 123(2), p.027206_1 - 027206_6, 2019/07

 被引用回数:3 パーセンタイル:33.41(Physics, Multidisciplinary)

Magnetic excitations of the effective spin $$S$$ =1/2 dimerized magnet Ba$$_{2}$$CoSi$$_{2}$$O$$_{6}$$Cl$$_{2}$$ have been probed directly via inelastic neutron scattering experiments. We observed five types of excitation, which are all dispersionless within the resolution limits. The scattering intensities of the three low-lying excitations were found to exhibit different $$Q$$-dependences. Detailed analysis has demonstrated that Ba$$_{2}$$CoSi$$_{2}$$O$$_{6}$$Cl$$_{2}$$ is a two dimensional spin dimer system described only by a single dimer site, where the triplet excitations are localized owing to the almost perfect frustration of the interdimer exchange interactions and the undimerized spins, even in small concentration, make an essential contribution to the excitation spectrum.


Triplon band splitting and topologically protected edge states in the dimerized antiferromagnet

那波 和宏*; 田中 公人*; 栗田 伸之*; 佐藤 卓*; 杉山 晴紀*; 植草 秀裕*; 河村 聖子; 中島 健次; 田中 秀数*

Nature Communications (Internet), 10, p.2096_1 - 2096_8, 2019/05

 被引用回数:15 パーセンタイル:77.34(Multidisciplinary Sciences)



Electrochemical adsorption on Pt nanoparticles in alkaline solution observed using in situ high energy resolution X-ray absorption spectroscopy

草野 翔吾*; 松村 大樹; 石井 賢司*; 田中 裕久*; 水木 純一郎*

Nanomaterials (Internet), 9(4), p.642_1 - 642_14, 2019/04

 被引用回数:4 パーセンタイル:26.19(Chemistry, Multidisciplinary)

The oxygen reduction reaction (ORR) on Pt/C in alkaline solution was studied by in situ high energy resolution X-ray absorption spectroscopy. To discuss the X-ray absorption near-edge structure (XANES), this paper introduced the rate of change of the $$Delta mu$$ (RCD), which is an analysis method that is sensitive to surface adsorption. The surface adsorptions as hydrogen (below 0.34 V), superoxide anion (from 0.34 V to 0.74 V), hydroxyl species (from 0.44 V to 0.74 V), atomic oxygen (above 0.74 V), and $$alpha$$-PtO$$_{2}$$ (above 0.94 V) were distinguished. It is clarified that the catalytic activity in an alkaline solution is enhanced by the stability of atomic oxygen and the low stability of superoxide anion/peroxide adsorption on the platinum surface.

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