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Electrochemically driven specific alkaline metal cation adsorption on a graphene interface

保田 諭; 田村 和久; 加藤 優*; 朝岡 秀人; 八木 一三*

Journal of Physical Chemistry C, 125(40), p.22154 - 22162, 2021/10




米田 安宏; 吉越 章隆; 竹田 幸治; 塩飽 秀啓; 松村 大樹; 菖蒲 敬久; 田村 和久

まてりあ, 58(12), p.763 - 769, 2019/12



Controlled deuterium labelling of imidazolium ionic liquids to probe the fine structure of the electrical double layer using neutron reflectometry

阿久津 和宏*; Cagnes, M.*; 田村 和久; 金谷 利治*; Darwish, T. A.*

Physical Chemistry Chemical Physics, 21(32), p.17512 - 17516, 2019/08

 被引用回数:3 パーセンタイル:32.79(Chemistry, Physical)



Structure of active sites of Fe-N-C nano-catalysts for alkaline exchange membrane fuel cells

岸 浩史*; 坂本 友和*; 朝澤 浩一郎*; 山口 進*; 加藤 豪士*; Zulevi, B.*; Serov, A.*; Artyushkova, K.*; Atanassov, P.*; 松村 大樹; et al.

Nanomaterials (Internet), 8(12), p.965_1 - 965_13, 2018/12

 被引用回数:6 パーセンタイル:39.54(Chemistry, Multidisciplinary)

Platinum group metal-free catalysts based on transition metal-nitrogen-carbon nanomaterials have been studied by a combination of in situ X-ray spectroscopy techniques, high-resolution transmission electron microscope, M$"o$ssbauer spectroscopy, electrochemical methods and density functional theory. Fe-N-C oxygen reduction reaction electrocatalysts were synthesized by varying several synthetic parameters to obtain nanomaterials with different composition and morphology. Associated with Fe-N$$_x$$ motive and the presence of Fe metallic particles in the electrocatalysts showed the clear differences in the variation of composition; processing and treatment conditions of sacrificial support method. From the results of material characterization; catalytic activity and theoretical studies; Fe metallic particles (coated with carbon) are main contributors into the HO$$_{2}$$$$^{-}$$ generation.


Reversible structural changes and high-rate capability of Li$$_{3}$$PO$$_{4}$$-modified Li$$_{2}$$RuO$$_{3}$$ for lithium-rich layered rocksalt oxide cathodes

田港 聡*; 平山 雅章*; 鈴木 耕太*; Kim, K.-S.*; 田村 和久; 菅野 了次*

Journal of Physical Chemistry C, 122(29), p.16607 - 16612, 2018/07

 被引用回数:6 パーセンタイル:37.83(Chemistry, Physical)



Electrochemical reaction mechanisms under various charge-discharge operating conditions for Li$$_{1.2}$$Ni$$_{0.13}$$Mn$$_{0.54}$$Co$$_{0.13}$$O$$_{2}$$ in a lithium-ion battery

小西 宏明*; 平野 辰巳*; 高松 大郊*; 軍司 章*; Feng, X.*; 古月 翔*; 奥村 壮文*; 寺田 尚平*; 田村 和久

Journal of Solid State Chemistry, 262, p.294 - 300, 2018/06

 被引用回数:6 パーセンタイル:51.04(Chemistry, Inorganic & Nuclear)

Li$$_{1.2}$$Ni$$_{0.13}$$Mn$$_{0.54}$$Co$$_{0.13}$$O$$_{2}$$正極の充電過程において、各SOCでの電極電位は、放電過程より高い。この機構を明らかにするために、様々なSOCにおいて電気化学測定、XRD, XAFS測定を行った。その結果、Li$$_{1.2}$$Ni$$_{0.13}$$Mn$$_{0.54}$$Co$$_{0.13}$$O$$_{2}$$の格子状数や遷移金属の酸化状態が異なっていることが分かった。また、Li$$_{1.2}$$Ni$$_{0.13}$$Mn$$_{0.54}$$Co$$_{0.13}$$O$$_{2}$$中に、LiNi$$_{0.33}$$Mn$$_{0.33}$$Co$$_{0.33}$$O$$_{2}$$やLi$$_{2}$$MnO$$_{3}$$に類似した構造が存在することも明らかになった。


Mechanisms responsible for two possible electrochemical reactions in Li$$_{1.2}$$Ni$$_{0.13}$$Mn$$_{0.54}$$Co$$_{0.13}$$O$$_{2}$$ used for lithium ion batteries

小西 宏明*; 平野 辰巳*; 高松 大郊*; 軍司 章*; Feng, X.*; 古月 翔*; 奥村 壮文*; 寺田 尚平*; 田村 和久

Journal of Solid State Chemistry, 258, p.225 - 231, 2018/02

 被引用回数:7 パーセンタイル:57.15(Chemistry, Inorganic & Nuclear)



Study on the deterioration mechanism of layered rock-salt electrodes using epitaxial thin films; Li(Ni, Co, Mn)O$$_{2}$$ and their Zr-O surface modified electrodes

阿部 真知子*; 射場 英紀*; 鈴木 耕太*; 南嶋 宏映*; 平山 雅章*; 田村 和久; 水木 純一郎*; 齋藤 智浩*; 幾原 雄一*; 菅野 了次*

Journal of Power Sources, 345, p.108 - 119, 2017/03

 被引用回数:9 パーセンタイル:44.85(Chemistry, Physical)

Ni, Co, Mn三元系リチウムイオン電池正極材料について、その劣化機構について、電気化学測定、X線・中性子線測定により調べた。実験の結果、Ni, Co, Mn三元系正極は、層状岩塩型構造とスピネル構造で構成されており、充放電を繰り返すと、充放電に関与しないスピネル構造が表面を覆っていくことが分かった。一方で、Zr-Oで表面をコートした材料は劣化しないことが知られており、その原因を調べた結果、層状岩塩型構造が安定に存在し続けていることが分かった。さらに、電極/溶液界面のLi濃度を上昇していることも分かった。


NiO/Nb$$_{2}$$O$$_{5}$$/C hydrazine electrooxidation catalysts for anion exchange membrane fuel cells

坂本 友和*; 増田 晃之*; 吉本 光児*; 岸 浩史*; 山口 進*; 松村 大樹; 田村 和久; 堀 彰宏*; 堀内 洋輔*; Serov, A.*; et al.

Journal of the Electrochemical Society, 164(4), p.F229 - F234, 2017/01

 被引用回数:11 パーセンタイル:52.44(Electrochemistry)

NiO/ Nb$$_{2}$$O$$_{5}$$/C (8:1), (4:1), (2:1), NiO/C, and Ni/C catalysts for hydrazine electrooxidation were synthesized by an evaporation drying method followed by thermal annealing. Prepared catalysts were characterized by X-ray diffraction (XRD), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectrometry (EDS), and X-ray absorption fine structure (XAFS). The highest catalytic activity in mentioned above reactionwas found for Ni/C, followed by: NiO/Nb$$_{2}$$O$$_{5}$$/C (8:1), NiO/Nb$$_{2}$$O$$_{5}$$/C (4:1). NiO/Nb$$_{2}$$O$$_{5}$$/C (2:1) whiles NiO/C has almost no activity for hydrazine oxidation. It was explained by oxygen defect of NiO in NiO/ Nb$$_{2}$$O$$_{5}$$/C from XAFS analysis. The selectivity hydrazine electrooxidation as measured by ammonia production resulted in observation that metallic Ni surface facilitates N-N bond breaking of hydrazine, which was confirmed by density functional theory (DFT) calculations.


Mechanism study of hydrazine electrooxidation reaction on nickel oxide surface in alkaline electrolyte by in situ XAFS

坂本 友和*; 岸 浩史*; 山口 進*; 松村 大樹; 田村 和久; 堀 彰宏*; 堀内 洋輔*; Serov, A.*; Artyushkova, K.*; Atanassov, P.*; et al.

Journal of the Electrochemical Society, 163(10), p.H951 - H957, 2016/08

 被引用回数:21 パーセンタイル:75.3(Electrochemistry)

The catalytic process takes place on nickel oxide surface of a Ni oxide nano-particle decorated carbon support (NiO/C). In-situ X-ray absorption fine structure (XAFS) spectroscopy was used to investigate the reaction mechanism for hydrazine electrooxidation on NiO surface. The spectra of X-ray absorption near-edge structure (XANES) of Ni K-edge indicated that adsorption of OH$$^{-}$$ on Ni site during the hydrazine electrooxidation reaction. Density functional theory (DFT) calculations were used to elucidate and suggest the mechanism of the electrooxidation and specifically propose the localization of electron density from OH$$^{-}$$ to 3d orbital of Ni in NiO. It is found that the accessibility of Ni atomic sites in NiO structure is critical for hydrazine electrooxidation. Based on this study, we propose a possible reaction mechanism for selective hydrazine electrooxidation to water and nitrogen taking place on NiO surface as it is applicable to direct hydrazine alkaline membrane fuel cells.


Study on the behavior of halide ions on the Au(111) electrode surface in ionic liquids using surface X-ray scattering

田村 和久; 西畑 保雄

Journal of Physical Chemistry C, 120(29), p.15691 - 15697, 2016/07

 被引用回数:8 パーセンタイル:37.16(Chemistry, Physical)



Lithium intercalation and structural changes at the LiCoO$$_{2}$$ surface under high voltage battery operation

田港 聡*; 平山 雅章*; 鈴木 耕太*; 田村 和久; 湊 丈俊*; 荒井 創*; 内本 喜晴*; 小久見 善八*; 菅野 了次*

Journal of Power Sources, 307, p.599 - 603, 2016/03

 被引用回数:26 パーセンタイル:73.4(Chemistry, Physical)




坂本 友和*; 岸 浩史*; 山口 進*; 田中 裕久*; 松村 大樹; 田村 和久; 西畑 保雄

表面科学, 37(2), p.78 - 83, 2016/02




菅野 了次*; 平山 雅章*; 鈴木 耕太*; 田村 和久

表面科学, 37(2), p.52 - 59, 2016/02



Interfacial analysis of surface-coated LiMn$$_{2}$$O$$_{4}$$ epitaxial thin film electrode for lithium batteries

鈴木 耕太*; 平山 雅章*; Kim, K.-S.*; 田港 聡*; 田村 和久; Son, J.-Y.*; 水木 純一郎; 菅野 了次*

Journal of the Electrochemical Society, 162(13), p.A7083 - A7090, 2015/08

 被引用回数:8 パーセンタイル:33.81(Electrochemistry)



Operando XAFS study of carbon supported Ni, NiZn, and Co catalysts for hydrazine electrooxidation for use in anion exchange membrane fuel cells

坂本 友和*; 松村 大樹; 朝澤 浩一郎*; Martinez, U.*; Serov, A.*; Artyushkova, K.*; Atanassov, P.*; 田村 和久; 西畑 保雄; 田中 裕久*

Electrochimica Acta, 163, p.116 - 122, 2015/05

 被引用回数:43 パーセンタイル:81.3(Electrochemistry)

Carbon supported Ni, Ni$$_{0.87}$$Zn$$_{0.13}$$, and Co hydrazine electrooxidation catalysts were synthesized by an impregnation/freeze-drying procedure followed by thermal annealing for use as anode catalyst of direct hydrazine hydrate fuel cells (DHFCs). The cell performance of DHFCs changed significantly when different catalysts were used as anode. Ammonia generation from anode outlet at open circuit voltage (OCV) condition was higher for Co/C than for Ni-based catalysts. To better understand the cause of different performance and selectivity of each anode catalyst, extensive ex-situ and operando characterization was carried out. Operando XAFS measurement of Ni-K and Co-$$K$$ edge shows the potential dependence of atomic structure of Ni/C, Ni$$_{0.87}$$Zn$$_{0.13}$$/C, and Co/C during hydrazine electrooxidation reaction.


Mechanistic studies on lithium intercalation in a lithium-rich layered material using Li$$_{2}$$RuO$$_{3}$$ epitaxial film electrodes and ${{it in situ}}$ surface X-ray analysis

田港 聡*; 平山 雅章*; 鈴木 耕太*; Kim, K.-S.*; Zheng, Y.*; 田村 和久; 水木 純一郎; 菅野 了次*

Journal of Materials Chemistry A, 2(34), p.17875 - 17882, 2014/11

 被引用回数:20 パーセンタイル:60.96(Chemistry, Physical)



In situ XAFS and HAXPES analysis and theoretical study of cobalt polypyrrole incorporated on carbon (CoPPyC) oxygen reduction reaction catalysts for anion-exchange membrane fuel cells

朝澤 浩一郎*; 岸 浩史*; 田中 裕久*; 松村 大樹; 田村 和久; 西畑 保雄; Saputro, A. G.*; 中西 寛*; 笠井 秀明*; Artyushkova, K.*; et al.

Journal of Physical Chemistry C, 118(44), p.25480 - 25486, 2014/11

 被引用回数:13 パーセンタイル:44.39(Chemistry, Physical)

Non-noble metal electrocatalysts not only are a solution to limited resources but also achieve higher efficiency for fuel cells, especially in alkaline media such as alkaline membrane fuel cells. Co-polypyrrole-based electrocatalysts provide high oxygen reduction reaction (ORR) reactivity, but the active sites and reaction mechanism have yet to be elucidated fully. In this study, ex situ and in situ synchrotron characterization and theoretical study have been combined to evaluate the ORR mechanism on two possible active sites consisting of Co coordinated with pyrrolic nitrogen and Co coordinated with pyridinic nitrogen.


Origin of the enhancement of electrocatalytic activity and durability of PtRu alloy prepared from a hetero binuclear Pt-Ru complex for methanol oxidation reactions

大川 侑久*; 増田 卓也*; 上原 広充*; 松村 大樹; 田村 和久; 西畑 保雄; 魚崎 浩平*

RSC Advances (Internet), 3(35), p.15094 - 15101, 2013/09

 被引用回数:9 パーセンタイル:39.22(Chemistry, Multidisciplinary)

PtRu alloy, prepared by pyrolysis of hetero bi-nuclear PtRu complexes, showed a higher electrocatalytic activity and durability in the methanol oxidation reaction than PtRu alloy prepared by pyrolysis. The origin of this activity enhancement was investigated by XPS and Ru K edge XAFS measurements. Although both alloys were composed of metallic Pt and Ru oxide, the Ru oxide in the PtRu alloy prepared from the PtRu complex had greater oxygen deficiency than that in the PtRu alloy. XAFS measurements showed that the RuO distance of the former was longer than that of the latter, suggesting the presence of the weakly coordinated oxygen species, water, in the PtRu alloy prepared from the PtRu complex. The water coordinated to Ru can become an active oxidant, surface RuOH, under electrochemical conditions and enhance MOR activity and durability.


Structure of Pt(111)/ionomer membrane interface and its bias-induced change in membrane electrode assembly

増田 卓也*; 福満 仁志*; 近藤 敏啓*; 猶原 秀夫*; 田村 和久; 坂田 修身*; 魚崎 浩平*

Journal of Physical Chemistry C, 117(23), p.12168 - 12171, 2013/06

 被引用回数:14 パーセンタイル:48.56(Chemistry, Physical)


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