Topics in Catalysis

, Volume 46, Issue 3–4, pp 263–275 | Cite as

XPS Structural Studies of Nano-composite Non-platinum Electrocatalysts for Polymer Electrolyte Fuel Cells

  • Kateryna Artyushkova
  • Stephen Levendosky
  • Plamen Atanassov
  • Julia Fulghum
Original Paper

Abstract

The chemical structure of non-platinum electrocatalysts obtained from cobalt porphyrins (CoTMPP or CoTPP) by pyrolysis is investigated by X-ray Photoelectron Spectroscopy (XPS). The catalysts represent highly dispersed, self-supported nano-composites that demonstrate electrocatalytic performance for oxygen reduction and practically no activity in methanol electro-oxidation. High-resolution Co2p, C1s, N1s and O1s XPS spectra acquired from precursors and electrocatalysts pyrolyzed at various experimental conditions were curve-fit using (a) individual peaks of constrained width and shape as well as (b) experimentally obtained photopeaks from the precursor with additional peaks required for a complete curve fit. Principal Component Analysis (PCA) applied to quantitative results from the curve-fits of both types of spectra facilitates visualization and identification of the chemical species that are formed or destroyed, and simplifies evaluation of critical correlations. As a result of these studies it is established that the catalyst is a nano-composite of highly dispersed pyropolymer with some remaining Nx-centers inserted into a graphite-like matrix. Approximately 50% of the metal is distributed as Co2+, associated with N4-centers. The remaining cobalt is present in crystallites of metallic Co. A thin layer of CoO coats these metallic cobalt phases. The developed methodology, described herein, combines model curve-fits and principal component analysis (PCA), resulting in a quantitative and unambiguous understanding of the chemical composition and structure of complex electrocatalysts.

Keywords

Non-platinum electrocatalysts Structural studies XPS Multivariate analysis PCA 

References

  1. 1.
    Levendosky S, Atanassov P, Davey J, Zelenay P (2004) The Electrochemical Society, Meeting Abstracts, abs. 321, 205th meetingGoogle Scholar
  2. 2.
    Gouerec IP, Savy M (1999) Electrochim Acta 44:2653CrossRefGoogle Scholar
  3. 3.
    Gojkovic SJ, Gupta S, Savinell RF (1999) J Electroanal Chem 462:64CrossRefGoogle Scholar
  4. 4.
    Sun GQ, Wang JT, Savinell RF (1999) J Appl Electrochem 28:1087CrossRefGoogle Scholar
  5. 5.
    Chu D, Jiang R (2002) Solid State Ionics 148:591CrossRefGoogle Scholar
  6. 6.
    Biloul A, Contamin O, Scarbeck G, Savy M, Vandenham D, Riga J, Verbist JJ (1992) J Electroanal Chem 335:163CrossRefGoogle Scholar
  7. 7.
    Ladouceur M, Lalande G, Guay D, Dodelet JP, Dignardbailey L, Trudeau ML, Schulz R (1993) J Electrochm Soc 140:1974CrossRefGoogle Scholar
  8. 8.
    Lalande G, Cote R, Tamizhmani G, Guay D, Dodelet JP, Dignardbailey L, Wengands LT, Bertrand P (1995) Electrochim Acta 40:2635CrossRefGoogle Scholar
  9. 9.
    Biloul A, Gouerec P, Savy M, Scarbeck G, Besse S, Riga J (1996) J Appl Electrochem 26:1139CrossRefGoogle Scholar
  10. 10.
    Gouerec P, Savy M, Riga J (1998) J Electrochim Acta 43:743CrossRefGoogle Scholar
  11. 11.
    Gojkovic SL, Gupta S, Savinell RF (1998) J Electrochm Soc 145:3493CrossRefGoogle Scholar
  12. 12.
    Gouerec P, Savy M (1999) Electrochim Acta 44:2653CrossRefGoogle Scholar
  13. 13.
    He P, Lefevre M, Faubert G, Dodelet JP (1999) J New Mater Electrochem Syst 2:243Google Scholar
  14. 14.
    Jiang DE, Zhao BY, Huang HZ, Xie YC, Pan GC, Ran GP, Min EZ (2000) Appl Catalysis A-General 192:1CrossRefGoogle Scholar
  15. 15.
    Wei G, Wainright JS, Savinell RF (2000) J New Mater Electrochem Syst 3:121Google Scholar
  16. 16.
    Bron M, Radnik J, Fieber-Erdmann M, Bogdanoff P, Fiechter S (2002) J Electroanal Chem 535:113CrossRefGoogle Scholar
  17. 17.
    Villers D, Jacques-Bedard X, Dodelet JP (2004) J Electrochm Soc 151:A1507CrossRefGoogle Scholar
  18. 18.
    Sawai K, Suzuki N (2004) J Electrochm Soc 151:A682CrossRefGoogle Scholar
  19. 19.
    Yeager EJ (1986) Mol Catal 38:5CrossRefGoogle Scholar
  20. 20.
    Van Veen JA, van Baar J, Kroese K (1981) J Chem Soc Faraday I 77:2827CrossRefGoogle Scholar
  21. 21.
    Faubert G, Cote R, Guay D, Dodelet JP, Denes G, Poleunis C, Bertrand B (1998) Electrochim Acta 43:1959Google Scholar
  22. 22.
    Scherson DA, Tanaka AA, Gupta SL, Tryk D, Fiert C, Yeager EB (1992) The Electrochemical Society Proceedings Series. Pennington, PV 92/11, New Jersey, p 555Google Scholar
  23. 23.
    Jaouen F, Marcotte S, Dodelet JP, Lindbergh G (2003) J Phys Chem B 107:1376CrossRefGoogle Scholar
  24. 24.
    Wojtowicz MA, Pels JR, Moulijn JA (1995) Fuel 74:507CrossRefGoogle Scholar
  25. 25.
    Kelemen SR, Gorbaty ML, Kwiatek PJ (1995) Energia 6Google Scholar
  26. 26.
    PLS_Toolbox 2.0. Eigenvector Research, Inc., Manson, WashingtonGoogle Scholar
  27. 27.
    Dignard-Bailey L, Trudeau ML, Joly A, Schulz R, Lalande G, Guay D, Dodelet JP (1994) J Material Res 9:3203CrossRefGoogle Scholar
  28. 28.
    Hair JF, Tatham RL, Anderson RE, Black W (1998) Multivariate data analysis. Prentice Hall, Upper Saddle River, NJGoogle Scholar
  29. 29.
    Malinowski ER (2002) Factor analysis in chemistry. Wiley, New YorkGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Kateryna Artyushkova
    • 1
  • Stephen Levendosky
    • 1
  • Plamen Atanassov
    • 1
  • Julia Fulghum
    • 1
  1. 1.Chemical & Nuclear Engineering DepartmentUniversity of New MexicoAlbuquerqueUSA

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