Journal of Materials Science

, Volume 42, Issue 18, pp 7667–7672 | Cite as

Hydrogen adsorption studies in micro-size cobalt dots

  • Christian P. Romero
  • Jonathan I. Avila
  • Edgardo Cisternas
  • Guerau B. Cabrera
  • Alejandro L. CabreraEmail author
  • Kristiaan Temst
  • Margriet J. Van Bael


Hydrogen desorption curves were obtained from a sample composed of a square arrangement of Co dots with average diameter of 4.4 μm, separated by a distance of 11.6 μm. A macroscopic sample of Co dots grown on a 2.5 × 2.5 cm Si substrate was made by standard lithographic techniques and used in these experiments. Thermal programmed desorption (TPD) was performed under ultra-high vacuum conditions. Hydrogen TPD curves were obtained from a 1 × 1 cm Co dots samples displaying a maximum of intensity at 425 K. Hydrogen TPD curve was also obtained from 1 cm× 1 cm samples of Co films and Co foils for comparison. The hydrogen TPD curves have decreasing intensity from the Co foils to the Co dots and finally to the Co films. This indicates that there are more sites for hydrogen adsorption on the Co dots than in the Co films. This is a surprising result because there is approximately 8.7 times less Co atoms exposed in the Co dots that in the Co film sample. A desorption energy of 27 kcal/mol was obtained for the Co dots suggesting that hydrogen is adsorbed on an hcp hollow site of the Co dot crystalline structure.


Atomic Force Microscopy High Resolution Transmission Electron Microscopy Hydrogen Adsorption Hydrogen Desorption Desorption Energy 



This research was partially supported by grants from the Chilean Government (FONDECYT 1030642 and 1060634), Fundacion Andes and MECESUP PUC0006 and UCh0205. We thank M. Moreno for SEM analyses, A. Zuñiga for HR-TEM analyses, M. Pino for XRD analyses, J. P. Staforelli and A. Pernas for helping with the TDS experiments and optical characterization of the Co dots.


  1. 1.
    Gryaznov VM (1986) Vestn Akad Nauk SSSR 21Google Scholar
  2. 2.
    Gryaznov VM (1986) Platinum Met Rev 30:68Google Scholar
  3. 3.
    Shu J, Grandjean BPA, Van Neste A, Kaliaguine S (1991) Can J Chem Eng 69:1036CrossRefGoogle Scholar
  4. 4.
    Klose F, Rehm Ch, Nagengast D, Maletta H, Weidinger A (1997) Phys Rev Lett 78:1150CrossRefGoogle Scholar
  5. 5.
    Rehm Ch, Fritzsche H, Maletta H, Klose F (1999) Phys Rev B 59:3142CrossRefGoogle Scholar
  6. 6.
    Lagos M (1982) Surf Sci Lett 122:L601Google Scholar
  7. 7.
    Lagos M, Schuller IK (1984) Surf Sci 138:L161CrossRefGoogle Scholar
  8. 8.
    Lagos M, Martinez G, Schuller IK (1985) Phys Rev B 29:5979CrossRefGoogle Scholar
  9. 9.
    Rieder KH, Baumberger M, Stocker W (1983) Phys Rev Lett 51:1799CrossRefGoogle Scholar
  10. 10.
    Vannice MA (1975) J Catal 37:449CrossRefGoogle Scholar
  11. 11.
    Somorjai GA (1981) Catal Rev Sci Eng 23:189CrossRefGoogle Scholar
  12. 12.
    Cabrera AL (1993) J Vac Sci Technol A 11(1):205CrossRefGoogle Scholar
  13. 13.
    Li Y, Erskine JL, Diebold AC (1986) Phys Rev B 34:5951CrossRefGoogle Scholar
  14. 14.
    Rieder KH, Stocker W (1986) Phys Rev Lett 57:2548CrossRefGoogle Scholar
  15. 15.
    Pick MA, Davenport JW, Strongin M, Dienes GJ (1979) Phys Rev Lett 43:286CrossRefGoogle Scholar
  16. 16.
    Pick MA (1981) Phys Rev B 24:4287CrossRefGoogle Scholar
  17. 17.
    Cabrera AL, Morales E, Altamirano L, Espinoza P (1993) Rev Mex Fis 39:932Google Scholar
  18. 18.
    Tarrach G, Lagos P, Hermans R (2001) Acta Microsc 10(Supplement 1):185Google Scholar
  19. 19.
    Cabrera AL (1993) J Vac Sci Technol A 11:205CrossRefGoogle Scholar
  20. 20.
    Somorjai GA (1994) Introduction to surface chemistry and catalysis. John Wiley & Sons, Inc., New York, p 313Google Scholar
  21. 21.
    Redhead PA (1962) Vacuum 12:203CrossRefGoogle Scholar
  22. 22.
    Cabrera AL, Espinosa-Gangas J, Jonsson-Akerman J, Schuller IK (2002) J Mater Res 17:2698CrossRefGoogle Scholar
  23. 23.
    Bridges M, Comrie C, Lambert R (1979) J Catal 58:28CrossRefGoogle Scholar
  24. 24.
    Klinke DJ II, Broadbelt LJ (1999) Surf Sci 429:169CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Christian P. Romero
    • 1
    • 3
  • Jonathan I. Avila
    • 1
  • Edgardo Cisternas
    • 1
  • Guerau B. Cabrera
    • 1
    • 4
  • Alejandro L. Cabrera
    • 1
    Email author
  • Kristiaan Temst
    • 2
  • Margriet J. Van Bael
    • 2
  1. 1.Facultad de FisicaPontificia Universidad Catolica de ChileCasilla 306Chile
  2. 2.Laboratorium voor Vaste-Stoffysica en MagnetismeK.U. LeuvenLeuvenBelgium
  3. 3.K.U. LeuvenLeuvenBelgium
  4. 4.Physics DepartmentWest Virginia UniversityMorgantownUSA

Personalised recommendations