イオン交換樹脂膜修飾白金マイクロ電極を用いるメタノール酸化反応における塩化物イオンの影響  [in Japanese] Influence of Cl^- ion additional on methanol electrooxidation at Nafion-modified Pt microelectrode  [in Japanese]

Search this Article

Author(s)

Abstract

直接メタノール形燃料電池の燃料極に,極微量のCl<sup>-</sup>イオンが混入した際の電極反応に及ぼす影響について研究を行った.これをモデル化するため,Pt電極にNafionを修飾したサンプルを作製し,Cl<sup>-</sup>イオンがメタノール酸化反応に及ぼす影響について電気化学測定による検討を行った.測定はNafion修飾Ptマイクロ電極(φ 50 μm)を用いた3電極式電位走査法により行った.マイクロ電極は,電極上に均質な膜を被覆させる目的で使用した.電解質溶液にはメタノールを含む硫酸溶液を使用し,これにKClを任意の濃度で溶解させた.電気化学測定の結果,(1)Cl<sup>-</sup>イオンはPt上で起こるPt表面酸化物(PtOH,PtO)の形成並びにメタノールの電極酸化反応を阻害し,プロトン伝導膜であるNafion膜はその阻害を抑制する,(2)しかし,Cl<sup>-</sup>イオンの一部はNafion膜を透過し,Pt触媒を被毒する,(3)Pt表面酸化物の形成が阻害されるとメタノールの酸化反応が起こりにくくなる,ことが明らかとなった.<br>

We have studied the influence of Cl<sup>−</sup>ion for methanol electrooxidation in direct methanol fuel cells (DMFCs) by using a Nafion-modified Pt microelectrode(φ 50 μm). The microelectrode was employed to form a uniform-thick Nafion overlayer on the Pt surface. Hg/Hg<sub>2</sub>SO<sub>4</sub> and Pt wire were used as a reference and a counter electrode, respectively. Current-potential curves were measured in a 0.5 M H<sub>2</sub>SO<sub>4</sub> or 0.5 M CH<sub>3</sub>OH + 0.5 M H<sub>2</sub>SO<sub>4</sub> solution. KCl was added into the solution at arbitrary rates. As a result, we have observed that (i)Cl<sup>−</sup>ion adsorbs on the Pt surface, which prohibited not only Pt oxide formation but also Methanol electrooxidation. The Nafion membrane prevented Cl<sup>−</sup>adsorption, because of it’s cation exchange property. (ii)However, a small part of Cl<sup>−</sup>ion was able to pass throughout Nafion membrane and adsorbs on the Pt surface. (iii) It has been known that a strong correlation exists between Pt surface oxide formation and methanol electrooxidation at a Pt electrode.<br>

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 53(10), 1055-1059, 2004-10-05

    The Japan Society for Analytical Chemistry

References:  20

  • <no title>

    APPLEBY A. J.

    Fuel Cell Handbook, 1989

    Cited by (13)

  • <no title>

    LARMINIE J.

    Fuel Cell Systems Explained, 2000

    Cited by (5)

  • <no title>

    CHEN J.

    J. Electroanal. Chem. 463, 93, 1999

    Cited by (3)

  • <no title>

    XIAO L.

    J. Electroanal. Chem. 495, 27, 2000

    Cited by (2)

  • <no title>

    FLEISCHMANN M.

    Ultra microelecttrodes, 1987

    Cited by (1)

  • <no title>

    BARD A. J.

    Electrochemical Methods, 2001

    Cited by (6)

  • <no title>

    OGUMI Z.

    J. Electrochem. Soc. 132, 2601, 1985

    Cited by (4)

  • <no title>

    GILMAN S.

    J. Phys. Chem. 67, 78, 1963

    Cited by (1)

  • <no title>

    BREITER M. W.

    Electrochim. Acta 8, 973, 1963

    Cited by (1)

  • <no title>

    GINER J.

    Electrochim. Acta 9, 63, 1964

    Cited by (1)

  • <no title>

    BARD Allen. J.

    Encyclopedia of Electrochemistry of the Elements VI, 170, 1976

    Cited by (1)

  • <no title>

    電気化学会

    電気化学便覧, 2000

    Cited by (5)

  • <no title>

    WATANABE M.

    J. Electroanal. Chem. 60, 259, 1975

    Cited by (4)

  • <no title>

    ZHU Y.

    Langmuir 17, 146, 2001

    Cited by (4)

  • <no title>

    UMEDE M.

    Electrochim. Acta 48, 1367, 2003

    Cited by (1)

  • <no title>

    MACROVIC N. M.

    Surface Science Reports 45, 117, 2002

    DOI  Cited by (1)

  • <no title>

    TU W. Y.

    J. Electroanal. Chem. 43, 3731, 1998

    Cited by (1)

  • <no title>

    WIGHTMAN R. M.

    Electroanalytical Chemistry 15, 267, 1989

    Cited by (11)

  • <no title>

    KOTER S.

    Separation and Purification Technology 22-23, 643, 2001

    Cited by (1)

  • <no title>

    IWASITA T.

    Electrochimi. Acta 47, 3663, 2002

    Cited by (3)

Codes

  • NII Article ID (NAID)
    110002905312
  • NII NACSIS-CAT ID (NCID)
    AN00222633
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    05251931
  • NDL Article ID
    7120966
  • NDL Source Classification
    ZP4(科学技術--化学・化学工業--分析化学)
  • NDL Call No.
    Z17-9
  • Data Source
    CJP  NDL  NII-ELS  J-STAGE  NDL-Digital 
Page Top