Carbon Reports
Online ISSN : 2436-5831
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Displaying 1-6 of 6 articles from this issue
Editorial Board
Review
  • Masayasu Nishi, Shih-Yuan Chen, Takehisa Mochizuki
    2024 Volume 3 Issue 1 Pages 2-10
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
    JOURNAL OPEN ACCESS

    Ammonia has garnered attention as a desired hydrogen carrier because of its high hydrogen content, ease of storage and transportation, and mature infrastructure. With the growing interest in H2 utilization, H2 production by ammonia decomposition has been recognized as a potential approach for a sustainable hydrogen society. There is therefore room for the development of a novel catalyst for low-temperature and highly efficient ammonia decomposition. Ru is considered the most active metal because of its strong interaction with nitrogen atoms. To achieve efficient ammonia decomposition, Ru-based catalysts have been investigated using various types of supports and promoters to modify the electronic and structural properties of Ru. Carbon materials, such as carbon nanotubes, carbon nanofibers, and graphene, have a high surface area, offering high Ru dispersion, which results in the formation of active sites for ammonia decomposition. Furthermore, recent research has speculated that carbon materials with highly graphitic structures, good electroconductivity, and nitrogen doping can improve the catalytic performance of the resulting Ru-based catalysts in ammonia decomposition by electron transfer from the carbon to the Ru.

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Research Papers
  • Yurika Taniguchi, Shinya Kokuryo, Ryuji Takada, Xinran Yang, Koji Miya ...
    2024 Volume 3 Issue 1 Pages 11-17
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
    Advance online publication: December 05, 2023
    JOURNAL OPEN ACCESS
    Supplementary material

    In recent years, N-doped carbon has emerged as an important electrode material because of its cost-effectiveness, high durability, and environmentally friendly characteristics. The catalytic activity of carbon atoms adjacent to nitrogen is contingent upon the position of nitrogen within the graphene lattice. Among various nitrogen species, pyridinic nitrogen is considered particularly effective in establishing an excellent active site for electrocatalytic applications. Nevertheless, achieving selective nitrogen doping poses challenges, given the high-temperature heat treatment required for carbon material synthesis. This study used pyridine, containing inherent pyridinic nitrogen with basicity, as the deposition source. The catalyst was synthesized using the zeolite template method, which allows adsorption on zeolite acid sites. The resulting catalysts showed a substantial presence of pyridinic N and high activity in oxygen reduction reactions (onset potential: 0.92 V vs. RHE).

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  • Da He, Koji Saito, Toru Kato, Chika Kosugi, Takaaki Shimohara, Koji Na ...
    2024 Volume 3 Issue 1 Pages 18-28
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
    Advance online publication: December 28, 2023
    JOURNAL OPEN ACCESS
    Supplementary material

    In the pursuit of carbon neutrality, marine biomass (MB) has emerged as a promising alternative to traditional carbon sources. This study endeavors to establish an economically viable pathway to derive porous carbon materials from MB. Simple pyrolysis of MB resulted in a MB-based carbon (MBC) characterized by a negligible open-pore structure. However, subsequent water washing transformed it into a porous material. N2 adsorption tests revealed that the pyrolysis temperature and washing method substantially influenced the specific surface area (SSA) and pore volume of the MBC. While the catalytic activation function of elements inherent in MB, such as Na, Mg, K, Ca, and Cl, rendered MBC inherently porous, these elements also induced an initial pore-blocking effect that concealed the pores. Subsequent washing with water nearly eradicated Na, K, and Cl from MBC, making a number of the concealed pores accessible. Furthermore, a CO2 aeration washing method effectively eliminated Mg and Ca elements from MBC, resulting in a substantial increase in SSA (>1000 m2/g) without the need for additional activation processes. Based on an understanding of the dual role of the elements naturally present in MB, this study demonstrates a potential strategy for environmentally friendly and cost-effective porous carbon production.

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  • Tomoya Takada, Yuuto Morikawa, Yasuki Kikuchi, Daiki Miyamoto, Yuuki H ...
    2024 Volume 3 Issue 1 Pages 29-36
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
    Advance online publication: December 28, 2023
    JOURNAL OPEN ACCESS

    The tensile elastic modulus and swelling of polyacrylamide/polyacrylic acid hydrogels was investigated to evaluate the effects of the gel structure (random copolymer and interpenetrating network) and reinforcement with multiwall carbon nanotubes (MWCNTs) on their mechanical properties. The tensile modulus of the interpenetrating network gels was significantly higher than that of random copolymer gels when compared at the same amount of swelling. This disparity can be explained by the difference in stiffness between the respective crosslinked polymers. The tensile modulus of both hydrogels increased when reinforced with MWCNTs, whereas the maximum amount of swelling decreased. The change in the mechanical and swelling properties after reinforcement with MWCNTs could be explained by the spatial distribution of hydrogen bonds between the MWCNT, acrylamide, and acrylic acid moieties.

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  • Yangzhou Zhao, Yasushi Ishiguro, Kousuke Nakamura, Hiroki Yoshimoto, T ...
    2024 Volume 3 Issue 1 Pages 37-46
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
    Advance online publication: December 29, 2023
    JOURNAL OPEN ACCESS

    Graphene in its isolated form is a promising material for applications in next-generation electronic devices; however, a strategy for modifying graphene to tune its carrier transport properties to meet requirements related to carrier density, electron mobility, and spin-orbit coupling is needed. We have modified graphene by irradiating it with a Au- or I-ion beam at 200 keV with doses of 1013–1014 cm−2 using a NaCl sacrificial layer as a quantitative chemical modification method. Ion-irradiated graphene was evaluated by Raman spectroscopy, electrical conductivity measurements, and Rutherford backscattering spectrometry after removing the sacrificial layer. Both carbon vacancies and heavy atoms (Au, I) are introduced into graphene by ion-beam irradiation; the introduced heavy atoms act as charged impurities, which results in the Raman D′ band and a downshift of the Fermi energy caused by hole carrier doping. Clearer knowledge of the influence of heavy-ion beam irradiation of graphene on electron transport properties will lead to the development of a new class of materials for electronics and spintronics.

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