Catalysis Letters

, Volume 12, Issue 1–3, pp 213–225 | Cite as

STM studies of the effect of pretreatment on the morphology and aspect ratio distribution of crystallites on Pt/HOPG

  • King Lun Yeung
  • E. E. Wolf


STM studies of chemically impregnated model Pt catalysts supported on HOPG substrate reveal the dynamics of morphological transformation from catalyst-intermediate to metal crystallites of near-equilibrium shape. Both the morphology and aspect ratio distribution of the crystallites undergo significant changes for catalysts reduced for 0.5, 2, and 60 h at similar pretreatment conditions. The aspect ratio distribution shows that majority (60–70%) of the crystallites have metastable shapes. Another model Pt catalyst was prepared by vacuum deposition of Pt metals onto the graphite substrate. Prior to H2 pretreatment, the Pt particles have random, irregular morphologies which transform to regular spherical shapes after H2 treatment at 250 °C for 30 min.


STM Pt/graphite pretreatment effect 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [1]
    G. Binnig, H. Rohrer, Ch. Gerber and E. Weibel, Phys. Rev. Lett. 50 (1983) 120.Google Scholar
  2. [2]
    A. Baratoff, G. Binnig, H. Fuchs, F. Salvan and E. Stoll, Surf. Sci. 168 (1986) 734.Google Scholar
  3. [3]
    R.J. Hamers and J.E. Demuth, Phys. Rev. Lett. 60 (1988) 2527.Google Scholar
  4. [4]
    Y. Kuk, P.J. Silverman and F.M. Chua, J. of Microscopy 152 (1988) 449.Google Scholar
  5. [5]
    Y. Kuk and P.J. Silverman, J. Vac. Sci. Technol. A 8 (1990) 289.Google Scholar
  6. [6]
    S. Rousset, S. Gauthier, O. Siboulet, W. Sacks, M. Belin and J. Klein, J. Vac. Sci. Technol. A 8 (1990) 302.Google Scholar
  7. [7]
    F.M. Chua, Y. Kuk and P.J. Silverman, J. Vac. Sci. Technol. A 8 (1990) 305.Google Scholar
  8. [8]
    R.J. Behm, W. Hosler, E. Ritter and G. Binnig, Phys. Rev. Lett. 56 (1986) 228.Google Scholar
  9. [9]
    L. Vazquez, J.M. Gomez Rodriguez, J. Gomez Herrero, A.M. Baro, N. Garcia, J.C. Canullo and A.J. Arvia, Surf. Sci. 181 (1987) 98.Google Scholar
  10. [10]
    J. Wintterlin, J. Wiechers, H. Brune, T. Gritsch, H. Hofer and R.J. Behm, Phys. Rev. Lett. 62 (1989) 59.Google Scholar
  11. [11]
    R. Nishitani, A. Kasuya, S. Kubota and Y. Nishina, J. Vac. Sci. Technol. B 9 (1991) 806.Google Scholar
  12. [12]
    A. Humbert, M. Dayez, S. Granjeaud, P. Ricci, C. Chapon and C.R. Henry, J. Vac. Sci. Technol. B 9 (1991) 802.Google Scholar
  13. [13]
    R. Moffat Kennedy, X. Yang and D. Fennel Evans, J. Vac. Sci. Technol. B 9 (1991) 735.Google Scholar
  14. [14]
    C. Becker, Th. Fries, K. Wandelt, U. Kreibig and G. Schmid, J. Vac. Sci. Technol. B 9 (1991) 810.Google Scholar
  15. [15]
    A.M. Baro, A. Bartolome, L. Vazquez, N. Garcia, R. Reifenberger, E. Choi and R.P. Andres, Appl. Phys. Lett. 51 (1987) 1594.Google Scholar
  16. [16]
    M. Komiyam, S. Morita and N. Mikoshiba, J. Microscopy 152 (1988) 197.Google Scholar
  17. [17]
    M. Komiyama, J. Kobayashi and S. Morita, J. Vac. Sci. Technol. A 8 (1990) 608.Google Scholar
  18. [18]
    King Lun Yeung and E.E. Wolf, J. Vac. Sci. Technol. B 9 (1991) 798.Google Scholar
  19. [19]
    J. Colchero, O. Marti, J. Mlynek, A. Humbert, C.R. Henry and C. Chapon, J. Vac. Sci. Technol. B. 9 (1991) 794.Google Scholar
  20. [20]
    U. Muller, K. Satter, J. Xhie, N. Venkateswaran and G. Raina, J. Vac. Sci. Technol. B. 9 (1991) 829.Google Scholar
  21. [21]
    W.L. Winterbottom, Acta Metall. 15 (1967) 303.Google Scholar
  22. [22]
    A.K. Datye, A.D. Logan and N.J. Long, J. Catal. 109 (1988) 76.Google Scholar
  23. [23]
    S. Chakraborti, A.K. Datye and N.J. Long, J. Catal. 108 (1987) 444.Google Scholar
  24. [24]
    J.C. Heyraud and J.J. Metois, J. Crystal Growth 50 (1980) 571.Google Scholar
  25. [25]
    T.G. Smith, Jr., W.B. Marks, G.D. Lange, W.H. Sheriff Jr. and E.A. Neale, J. Neurosci. Methods 27 (1989) 173.Google Scholar
  26. [26]
    D. Avnir,The Fractal Approach to Heterogeneous Chemistry;Surfaces;Colloids, Polymers (John Wiley & Sons, New York, 1989).Google Scholar

Copyright information

© J.C. Baltzer A.G. Scientific Publishing CompanyJ.C. Baltzer A.G. Scientific Publishing Company 1992

Authors and Affiliations

  • King Lun Yeung
    • 1
  • E. E. Wolf
    • 1
  1. 1.Department of Chemical EngineeringUniversity of Notre DameNotre DameUSA

Personalised recommendations