研究者詳細 - 川角　昌弥

論文 - 川角　昌弥

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Nitrogen-Containing Carbon-Encapsulated Platinum Electrocatalysts Supported by Single-Walled Carbon Nanotubes for Polymer Electrolyte Fuel Cells 招待有り査読有り

頁： 2500074 2025年

Improving the durability and anti-poisoning properties of platinum catalysts by carbon shell encapsulation: A promising approach for both cathode and anode catalysts for polymer electrolyte membrane fuel cells

Park, JH; Saito, N; Kawasumi, M

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 72 巻頁： 642 - 651 2024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：International Journal of Hydrogen Energy

Carbon shell encapsulation has emerged as an effective strategy for enhancing the durability of Pt-based electrocatalysts for polymer electrolyte membrane fuel cells (PEFCs). Here, a nitrogen-doped carbon shell-encapsulated Pt catalyst supported on Ketjen black (Pt@C/KB) was synthesized, and its catalytic performance was characterized. The oxygen reduction reaction (ORR) performance and anti-poisoning properties were investigated in 0.1 M HClO4 with and without H2SO4 or H3PO4 poisoning, using a rotating ring-disk electrode (RRDE) technique. Despite a decrease in the electrochemical surface area (ECSA), Pt@C/KB encapsulated by a thin graphene-like carbon shell (<1 nm thick) showed high selectivity for the four-electron reaction due to its superior anti-poisoning properties, as well as improved ORR activity and durability. The H2O2 yield of Pt@C/KB, the precursor of hydroxyl radicals, was decreased approximately one third compared to bare Pt catalyst and the gap was more pronounced in the low potential (E ≤ 0.1 V/RHE) where close to practical anode potential, suggesting that Pt@C/KB can be applied as a new anode catalyst. Applying carbon core-shell catalysts to both the cathode and anode is a prospectively effective approach for improving the cell performance by improving the ORR activity and anti-poisoning properties, as well as for extending the lifespan of PEFCs.

DOI： 10.1016/j.ijhydene.2024.05.394

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Single-Walled Carbon Nanotubes Supported Pt Electrocatalyst as a Cathode Catalyst of a Single Fuel Cell with High Durability against Start-up/Shut-down Potential Cycling

Huda, M; Kawahara, T; Park, JH; Kawasumi, M; Matsuo, Y

ACS APPLIED ENERGY MATERIALS 6 巻 ( 24 ) 頁： 12226 - 12236 2023年12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：ACS Applied Energy Materials

Carbon nanotubes (CNTs) have remarkable properties such as high conductivity, high porosity, and high oxidation resistance, which make them excellent candidates for supporting electrocatalysts in proton exchange membrane fuel cells (PEMFCs). In this study, high-crystallinity, high-purity single-walled carbon nanotubes (SWCNTs), which were prepared by enhanced direct injection pyrolytic synthesis (e-DIPS), were used as a support for a metal electrocatalyst. Platinum (Pt) nanoparticles of uniform size were synthesized by a facile solvothermal method and distributed evenly on the surface of the SWCNTs (Pt/SWCNT). Electrochemical measurements using cyclic voltammetry and linear sweep voltammetry showed that the Pt/SWCNT exhibited higher mass activity and specific activity compared to commercial Pt nanoparticles supported on graphitized carbon (Pt/C). A PEMFC membrane electrode assembly (MEA) utilizing Pt/SWCNT as the cathode layer (Pt/SWCNT-MEA) with low Pt loading demonstrated high-efficiency performance with power density per gram of Pt that was three times higher than that of Pt/C. Furthermore, in a durability test using a high-voltage triangular wave between 1.0 and 1.5 V to induce corrosion of the catalyst and carbon support, simulating harsh conditions of actual repeated start-up/shut-down cycles during long-term use, the Pt/SWCNT-MEA retained high performance even after 10,000 potential cycles. These results indicate that SWCNTs show promise as an excellent support material for electrocatalysts, offering high performance and durability, and thus can contribute to realizing PEMFCs with superior performance.

DOI： 10.1021/acsaem.3c01919

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Highly durable graphene-encapsulated platinum-based electrocatalyst for oxygen reduction reactions synthesized by solution plasma process

Park, JH; Kim, K; Wang, XY; Huda, M; Sawada, Y; Matsuo, Y; Saito, N; Kawasumi, M

JOURNAL OF POWER SOURCES 580 巻 2023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：Journal of Power Sources

Though expensive platinum (Pt) is used as catalyst for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs), insufficient durability remains as a bottleneck for commercialization of PEFCs. Improving both catalytic performance and durability by graphene encapsulation is an attractive strategy to solve this problem. In this study, graphene-encapsulated PtFe core-shell catalyst is synthesized with dimethyl formamide (DMF) and a pair of Pt and Fe electrodes without using any metal salts by utilizing the solution plasma (SP) process. TEM and EELS results show synthesized PtFe nanoparticles are encapsulated with close to single-layered highly crystallized graphene. Although commercial Pt/C showed significant performance degradation (ECSA −33%, MA −68%) after 50,000 cycles of accelerated durability test (ADT), PtFe core-shell catalyst shows remarkably improved durability (ECSA −13%, MA −19%) while graphene shell clearly remains. The improved durability is more prominent in the single cell test, the decrease in maximum power density after 6000 cycles of ADT was significantly lower as −1.2%, compared to that of Pt/C (−52.1%). This study introduces a novel and attractive catalyst synthesis process by the SP method followed by heat treatments and suggests graphene encapsulation can improve long-term durability of catalyst while maintaining ORR activity.

DOI： 10.1016/j.jpowsour.2023.233419

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Novel solution plasma synthesis of highly durable carbon shell encapsulated platinum-based cathode catalyst for polymer electrolyte membrane fuel cells

Park, JH; Saito, N; Kawasumi, M

CARBON 214 巻 2023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：Carbon

Developing an effective method for synthesizing high-performance and durable catalysts for the oxygen reduction reaction is of great importance for cost reduction and the wide application of fuel cells. This study presents a simple and effective strategy using a plasma reaction in the liquid phase to synthesize carbon-shell-encapsulated Pt and PtFe catalysts. A carbon-shell-encapsulated PtFe catalyst alloyed with up to 29 at.% Fe exhibits a mass activity of 730 mA·mgpt−1 and a specific activity of 1772 μA cm−1, which are 2.4 and 5 times higher than that of commercial Pt/C, respectively. The carbon shell effectively maintained the low oxidation state of Pt by suppressing the formation of Pt–OH and significantly improved the durability of the catalyst in accelerated durability tests, increasing the gap in mass activity with Pt/C by a factor of up to six after 50,000 cycles. In addition, the decrease in the electrochemical surface area by the carbon shell enabled a more stable 4-electron reaction over a wide potential range. This study may provide fascinating insights into the effect of the carbon shell contributing to the improvement of the catalytic activity and durability of fuel cells as well as the novel plasma-based synthesis strategy of core-shell catalyst.

DOI： 10.1016/j.carbon.2023.118364

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Efficient CO2/Electrochemical Reduction by a Robust Electrocatalyst Fabricated by Electrodeposition of Indium and Zinc over Copper Foam

Sirisomboonchai, S; Machida, H; Tran, KVB; Kawasumi, M; Norinaga, K

ACS APPLIED ENERGY MATERIALS 5 巻 ( 8 ) 頁： 9846 - 9857 2022年8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：ACS Applied Energy Materials

Electrochemical reduction of CO2comprising the CO2reduction reactuib (CO2RR) and oxygen evolution reaction (OER) is one of the most promising technologies for electrification of the chemical process industry. Here, the performance of a electrocatalyst with a three-dimensional structure of InZnCu on Cu foam (CF) is presented. This electrocatalyst was fabricated by electrodeposition of In and Zn over Cu and exhibited a superior reduction of CO2to CO at a Faradaic efficiency of 93.7% at -0.7 V and an excellently long duration of 100 h. Due to the synergy of the thin In layer, the Zn nanosheets provided a high surface-active area and strong mechanical robustness during the reaction. Additionally, a two-electrode system was constructed based on the CF-modified surface, which provided valuable guidelines on the overall CO2RR-OER system for further evolution. Furthermore, due to the facile synthesis, the bimetal-layer double hydroxide (LDH) exhibited high conductivity and high OER performance. Hence, the two-electrode system assembled excellent electrocatalysts for the CO2RR-OER (InZnCu/CF||Cu(OH)2NWs@NiCo-LDH/CF) with high conversions of CO2to CO of 67% and 88% at 2 and 50 mA cm-2, respectively. Notably, the CO2RR-OER system exhibited excellent stability in a 40 h CO2conversion with a constant current density of 2 mA cm-2at an ultralow voltage of 1.59 V. Moreover, the calculation of the energy input converting CO per ton of CO2resulted in a low energy input range for further development in scalability. This overall CO2RR-OER proposes development in electrochemical CO2reduction for industrial applications.

DOI： 10.1021/acsaem.2c01564

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Synthesis and Properties of Fluorocarbon–Hydrocarbon Hybrid Block Copolymers with Perfluorosulfonimide Acid 査読有り

5 巻 ( 43 ) 頁： 27766 - 27773 2020年10月

Nanocomposites Based on Organic and Inorganic Materials and Their unique Properties and Functions

川角　昌弥

R&D Review of Toyota CRDL 50 巻 ( 2 ) 頁： 45 - 61 2019年

Properties of a Novel Imide Network Polymer Electrolyte and Fuel Cell Performance of Its Composite Membrane

Kyoko Tsusaka, Naoki Kitano, Takashi Yamamoto, Naoki Hasegawa, Akihiko Koiwai, Masaya Kawasumi

R&D Review of Toyota CRDL 49 巻 ( 4 ) 頁： 21 - 31 2018年

Imide Crosslinked Perfluorinated Proton Exchange Membranes by Gas Treatment

Tsusaka Kyoko, Yamamoto Takashi, Asano Takashi, Muto Atsuko, Hasegawa Naoki, Kawasumi Masaya

JOURNAL OF THE ELECTROCHEMICAL SOCIETY 163 巻 ( 5 ) 頁： F372 - F376 2016年

スルホン酸修飾メソポーラスシリカ(乾燥状態)のプロトンダイナミクス

蒲沢和也, 藤田悟, 荒木暢, 長谷川直樹, 川角昌弥, Madhusudan Tyagi, 杉山純

日本物理学会講演概要集 69.2.4 巻 2014年8月

Ion Conductive Organic-inorganic Hybrid Electrolyte with Meso-scale Proton Channels for Fuel Cells

Satoru Fujita, Kazuya Kamazawa, Satoru Yamamoto, Akihiko Koiwai, Shinji Inagaki, Jun Sugiyama, Masaya Kawasumi

R&D Review of Toyota CRDL 44 巻 ( 4 ) 頁： 59 - 69 2014年

Non-crosslinked perfluoro-polymer electrolytes with two acid groups and their properties

Akihiro Shinohara, Kenji Kudo, Masaya Kawasumi, Yu Morimoto, Naoki Hasegawa

ECS Transactions 58 巻 ( 1 ) 頁： 253 - 259 2013年8月

Enhancement of Proton Transport by High Densification of Sulfonic Acid Groups in Highly Ordered Mesoporous Silica

Fujita Satoru, Koiwai Akihiko, Kawasumi Masaya, Inagaki Shinji

CHEMISTRY OF MATERIALS 25 巻 ( 9 ) 頁： 1584 - 1591 2013年5月

Proton conductivity under dry conditions for mesoporous silica with highly dense sulfonic acid groups

Fujita S., Kamazawa K., Yamamoto S., Tyagi M., Araki T., Sugiyama J., Hasegawa N., Kawasumi M.

Journal of Physical Chemistry C 117 巻 ( 17 ) 頁： 8727 - 8736 2013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：Journal of Physical Chemistry C

Highly dense sulfonic acid-functionalized mesoporous electrolytes with high proton conductivity under dry conditions were prepared using tetramethoxysilane and 3-mercaptopropyltrimethoxysilane in the presence of surfactants. Impedance spectroscopy and quasielastic neutron scattering measurements showed that the proton conductive properties of the mesoporous electrolytes depended significantly on the sulfonic acid densities on the surface of the mesoporous walls. This finding was also supported by molecular dynamics simulations. The proton conductivity of the mesoporous electrolyte with the highest acid density of 3.1 SO3H molecules/nm2 showed a value of 0.3 mS/cm at 433 K even under dry conditions. This value was higher than that for Nafion by about 2 orders of magnitude. Such high proton conductivity is thought to be induced by proton hopping in the hydrogen-bonded networks that were predominantly formed by neighboring sulfonic acid groups. © 2013 American Chemical Society.

DOI： 10.1021/jp307058s

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Development and applications of polyolefin- and rubber-clay nanocomposites

Kato M., Usuki A., Hasegawa N., Okamoto H., Kawasumi M.

Polymer Journal 43 巻 ( 7 ) 頁： 583 - 593 2011年7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：Polymer Journal

A nylon 6-clay hybrid (nanocomposite, NCH) was developed by Toyota CRDL group. In the NCH, the silicate layers of clay mineral are dispersed on a nanometer level and are strongly interacted with the matrix, and then significant improvements in the mechanical properties of the material or the discovery of unexpected new properties were realized. Polypropylene (PP) is the most widely used polymer, and then an appearance of a PP-clay nanocomposite has been desired for a long time. As a PP does not include any polar groups in its backbone, it was thought that the homogeneous dispersion of the silicate layers would not be realized. But we have developed successfully PP-clay nanocomposite using organoclay and modified PP. That is, organophilic clay, PP oligomer carrying polar groups and PP were melt-blended. This is a direct polymer intercalation process for preparing polymer nanocomposites by melt compounding, a useful process from an industrial standpoint. We have also developed successfully other polyolefin polymers (polyethylene), polyolefin rubbers (ethylene-propylene elastomer, ethylene-propylene diene monomer) and nanocomposites by this direct polymer intercalation process or by techniques based on direct polymer intercalation process. These prepared polyolefin nanocomposites exhibit superior mechanical, thermal and gas barrier properties. © The Society of Polymer Science, Japan (SPSJ) All rights reserved.

DOI： 10.1038/pj.2011.44

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フッ素・炭化水素ブロック共重合電解質膜の合成と評価

星川尚弘，篠原朗大，細川洋一，長谷川直樹，川角昌弥

高分子学会予稿集頁： 4686 - 4686 2010年

Angular distribution of elemental composition of films deposited by laser ablation of a SrZrO3 target

Konomi I., Motohiro T., Horii M., Kawasumi M.

Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films 26 巻 ( 6 ) 頁： 1455 - 1461 2008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：Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films

The angular distributions of elemental composition of films prepared by laser ablation of perovskite oxide SrZrO3 have been investigated using electron probe microanalysis with wavelength-dispersive spectroscopy. Each constituent element showed two modal distribution composed of a broad cos m θ (m=2-3) distribution and a sharp cosn θ (n=8-23) distribution. Oxygen showed a broader distribution than that of Sr and Zr. At the polar angle close to surface normal direction (polar angle <12°), Zr concentration was higher than that of Sr in vacuum whereas in oxygen-containing atmosphere their concentrations were about the same. Below oxygen pressure of 1.3 Pa, Sr and Zr concentration increased and decreased with the increase in polar angle, respectively, whereas in oxygen partial pressure of 10 Pa, both elements showed no angular dependences. Broadening of angular distribution of all the elements was observed when deposition was performed under oxygen partial pressure of 10 Pa, which is considered to be caused by collisional scatterings of more than ten times with ambient gas molecules. © 2008 American Vacuum Society.

DOI： 10.1116/1.2987952

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Electrode and Membrane Durability Issues of PEFCs

Hatanaka Tatsuya, Takeshita Tomohiro, Murata Hajime, Hasegawa Naoki, Asano Takashi, Kawasumi Masaya, Morimoto Yu

PROTON EXCHANGE MEMBRANE FUEL CELLS 8, PTS 1 AND 2 16 巻 ( 2 ) 頁： 1961 - 1965 2008年

Degradation of Perfluorinated Membranes Having Intentionally Formed Pt-Band

Hasegawa Naoki, Asano Takashi, Hatanaka Tatsuya, Kawasumi Masaya, Morimoto Yu

PROTON EXCHANGE MEMBRANE FUEL CELLS 8, PTS 1 AND 2 16 巻 ( 2 ) 頁： 1713 - 1716 2008年

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