Updated on 2024/05/08

写真a

 
ANDO Atsushi
 
Organization
Center for Low-temperature Plasma Sciences (cLPS) Designated lecturer
Title
Designated lecturer
 

Papers 5

  1. In-Liquid Plasma Synthesis of Nanographene with a Mixture of Methanol and 1-Butanol

    Ando, A; Ishikawa, K; Takeda, K; Ohta, T; Ito, M; Hiramatsu, M; Kondo, H; Sekine, M; Hori, M

    CHEMNANOMAT   Vol. 6 ( 4 ) page: 604 - 609   2020.4

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    Publisher:ChemNanoMat  

    Nanometer-size graphene sheets (nanographene) were synthesized by the in-liquid plasma method employing a mixture of alcohols. Pure methanol in-liquid plasma was found to not synthesize any nanographene. Pure ethanol synthesized nanographene with high crystallinity. Highly crystalline nanographene with a narrow full width-half maximum of the Raman scattering G-band (FWHMG) was obtained by mixing 1-butanol with methanol. This is due to the formation of carbon ring structures being inhibited by the addition of methanol. The ratio of added methanol determined the nanographene crystallinity and yield under a trade-off relationship, allowing the crystallinity and nanographene yield to be controlled by controlling the ratio. Gas chromatography-mass spectrometric analysis of by-products in the liquids’ supernatant showed that the crystallinity of the synthesized nanographene correlated with the ratio of carbon over oxygen of the alcohol precursors (C/O), i. e., the amount of hydroxyl groups in the liquids, and hence controlling the C/O ratio can be used to control the graphene crystallinity in the in-liquid plasma synthesis.

    DOI: 10.1002/cnma.201900676

    Web of Science

    Scopus

  2. Impact of helium pressure in arc plasma synthesis on crystallinity of single-walled carbon nanotubes

    Ando, A; Takeda, K; Ohta, T; Ito, M; Hiramatsu, M; Ishikawa, K; Kondo, H; Sekine, M; Suzuki, T; Inoue, S; Ando, Y; Hori, M

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 57 ( 6 )   2018.6

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    Publisher:Japanese Journal of Applied Physics  

    Single-walled carbon nanotubes (SWNTs) were synthesized with a high growth rate by an arc plasma method employing the electrodes made from a Ni–Y mixture catalyst. In a previous study, it was reported that the monitoring of high-crystallinity SWNT growth enabled the evaluation of the results of the optical emission spectroscopy (OES) of C2, Ni, and Y. Here, the impact of helium pressure of arc plasma on the high crystallinity of SWNTs was determined by considering the high intensity ratios of catalytic metals over C2 emissions at low helium pressures in the arc plasma.

    DOI: 10.7567/JJAP.57.06JF01

    Web of Science

    Scopus

  3. Nanographene synthesis employing in-liquid plasmas with alcohols or hydrocarbons

    Ando, A; Ishikawa, K; Kondo, H; Tsutsumi, T; Takeda, K; Ohta, T; Ito, M; Hiramatsu, M; Sekine, M; Hori, M

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 57 ( 2 )   2018.2

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    Publisher:Japanese Journal of Applied Physics  

    Graphenes of nanometer-scale grain size (nanographenes) were synthesized using in-liquid plasmas with alcohols or hydrocarbons. This method of nanographene synthesis showed a trade-off relationship between crystallinity and synthesis rate. The high crystallinity of nanographenes synthesized with alcohols was evaluated from the small full width at half maxima (FWHM) of the G band in Raman scattering spectra. On the other hand, in the case of using hydrocarbons such as n-hexane and benzene, a significantly high synthesis rate was obtained but the crystallinity of nanographenes was low. It was found that hydroxyl groups and oxygen atoms of liquid sources play important roles in determining the crystallinity of synthesized nanographenes.

    DOI: 10.7567/JJAP.57.026201

    Web of Science

    Scopus

  4. Laser diagnostics of properties of atmospheric pressure plasmas

    Lin YuChun, Ando Atsushi, Ishikawa Kenji, Hori Masaru, Wang Meng-Jiy

    JSAP Annual Meetings Extended Abstracts   Vol. 2017.2 ( 0 ) page: 1701 - 1701   2017.8

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    Language:English   Publisher:The Japan Society of Applied Physics  

    DOI: 10.11470/jsapmeeting.2017.2.0_1701

    CiNii Research

  5. Characteristics of optical emissions of arc plasma processing for high-rate synthesis of highly crystalline single-walled carbon nanotubes

    Ando, A; Takeda, K; Ohta, T; Ito, M; Hiramatsu, M; Ishikawa, K; Kondo, H; Sekine, M; Suzuki, T; Inoue, S; Ando, Y; Hori, M

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 56 ( 3 )   2017.3

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    Publisher:Japanese Journal of Applied Physics  

    Single-walled carbon nanotubes (SWNTs) were synthesized with a high growth rate using an arc plasma employing carbon electrodes with a Ni-Y mixture catalyst. However, the mechanism of growth of highly crystalline SWNTs has not been clarified. Reactions between carbon and catalyst are considered to be one of the crucial factors in SWNT growth. Optical emission spectroscopy (OES) provides the information about the species in the plasma. C2, Ni, and Y emissions in the arc plasma at different currents were measured to investigate the relationship between active species in the arc plasma and the SWNTsynthesis. On the basis of OES results, it was found that the balance between catalytic metal atoms and C2 radical emissions indicated the crystallinity ratio of SWNTs in thin graphitic or amorphous carbon layers. These results are useful for controlling the growth of SWNTs employing arc plasmas.

    DOI: 10.7567/JJAP.56.035101

    Web of Science

    Scopus