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Kinetics of hydrogen desorption from palladium and ruthenium-palladium foils

Published online by Cambridge University Press:  03 March 2011

A.L. Cabrera ,
Erie Morales  and
J.N. Armor
A.L. Cabrera*
Affiliation:
Pontificia Universidad Catolica de Chile, Facultad de Fisica, Casilla 306, Santiago 22, Chile
Erie Morales
Affiliation:
Pontificia Universidad Catolica de Chile, Facultad de Fisica, Casilla 306, Santiago 22, Chile
J.N. Armor
Affiliation:
Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, Pennsylvania 18195
*
a)Author to whom correspondence should be addressed.
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Abstract

The absorption of hydrogen and carbon monoxide at room temperature by palladium and 5% ruthenium-palladium foils was studied using thermal desorption spectroscopy. It was found that hydrogen readily diffused in the palladium and desorbed as one broad peak at about 650 K. Plots of the In (rate) versus inverse absolute temperature indicate that the desorption order is n = 1.25 and the activation energy is about 8.5 Kcal/mol. Carbon monoxide is adsorbed, as two different states, on the surface of the foil and complete coverage is quickly reached below 100 L. Hydrogen also diffuses in 5% ruthenium-palladium foil but to a lesser degree. Two hydrogen desorption peaks are observed in the Ru-Pd alloy. The desorption traces can be fitted with two peaks and the desorption orders are n = 2 for the first peak and n = 1.25 for the second peak. Activation energies of 10.7 and 5.6 Kcal/mol are obtained for the first and second hydrogen peaks, respectively. The first hydrogen desorption peak is regarded as hydrogen desorbing from the surface sites while the second peak is regarded as hydrogen diffusing from below the surface. Activation energies for bulk diffusion were obtained from hydrogen uptake measurements using a sensitive microbalance. These energies corresponded to 4.4 Kcal/mol for Pd foil and 4.9 Kcal/mol for the Ru-Pd alloy. Discussion about the relation between these results with prior studies of hydrogen adsorption on Pd single crystal is included. The appearance of a fractional order for hydrogen desorption is also discussed.

Type
Articles
Information
Journal of Materials Research , Volume 10 , Issue 3 , March 1995 , pp. 779 - 785
Copyright
Copyright © Materials Research Society 1995

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References

REFERENCES

1Gryaznov, V. M., Vestn. Akad. Nauk SSSR, 21 (1986).Google Scholar
2Gryaznov, V. M., Platinum Met. Rev. 30, 68 (1986).CrossRefGoogle Scholar
3Shu, J., Grandjean, B.P. A., Van Neste, A., and Kaliaguine, S., Can. J. Chem. Eng. 69, 1038 (1991).CrossRefGoogle Scholar
4Lagos, M., Surf. Sci. Lett. 122, L601 (1982).Google Scholar
5Lagos, M. and Schuller, I. K., Surf. Sci. 138, L161 (1984).CrossRefGoogle Scholar
6Lagos, M., Martinez, G., and Schuller, I. K., Phys. Rev. B 29, 5979 (1985).CrossRefGoogle Scholar
7Li, Y., Erskine, J. L., and Diebold, A. C., Phys. Rev. B 34, 5951 (1986).CrossRefGoogle Scholar
8Rieder, K. H. and Stacker, W., Phys. Rev. Lett. 57 (20), 2548 (1986).CrossRefGoogle Scholar
9Rieder, K. H., Baumberger, M., and Stacker, W., Phys. Rev. Lett. 51 (19), 1799 (1983).CrossRefGoogle Scholar
10VanHove, M.A. and Hermann, K., Surface Architecture and Latuse, a PC-based program, Version 2.0, Lawrence Berkeley Lab. Berkeley, CA 1988.Google Scholar
11Daw, M. S. and Baskes, M. I., Phys. Rev. B 29 (12), 6443 (1985).CrossRefGoogle Scholar
12Conrad, H., Ertl, G., and Latta, E. E., Surf. Sci. 41, 435 (1974).CrossRefGoogle Scholar
13Behm, R. J., Christmann, K., and Ertl, G., Surf. Sci. 99, 1320 (1980).CrossRefGoogle Scholar
14Cattania, M. G., Penka, V., Behm, R. J., Christmann, K., and Ertl, G., Surf. Sci. 126, 382 (1983).CrossRefGoogle Scholar
15Nyberg, C., Westerlund, L., Jonsson, L., and Andersson, S., J. Electron Spectrosc. Rel. Phenom. 54/55, 639 (1990).CrossRefGoogle Scholar
16He, J-W. and Norton, P. R., Surf. Sci. 195, L199 (1988).CrossRefGoogle Scholar
17Lynch, J. F. and Flanagan, T. B., J. Phys. Chem. 77, 2628 (1973).CrossRefGoogle Scholar
18Behm, R. J., Penka, V., Cattania, M. G., Christmann, K., and Ertl, G., J. Chem. Phys. 78 (12), 7486 (1983).CrossRefGoogle Scholar
19Gdowski, G. E., Felter, T. E., and Stulen, R. H., Surf. Sci. 181, L147 (1987).CrossRefGoogle Scholar
20Auer, W. and Grabke, H. J., Ber. Bunsenges. 78, 58 (1974).CrossRefGoogle Scholar
21Kay, B. D., Peden, C. H. F., and Goodman, D. W., Phys. Rev. B 34, 817 (1986).CrossRefGoogle Scholar
22Armor, J. N. and Farris, T. S., Proceedings of the 13th International Congress on Catalysis, Budapest (1992).Google Scholar
23Behm, R. J., Christmann, K., Ertl, G., VanHove, M. A., Thiel, P. A., and Weinberg, W. H., Surf. Sci. 88, L59 (1979).CrossRefGoogle Scholar
24Behm, R. J., Christmann, K., Ertl, G., and VanHove, M. A., J. Chem. Phys. 73, 2984 (1980).CrossRefGoogle Scholar
25Noordermeer, A., Kok, G. A., and Niuwenhuys, B. E., Surf. Sci. 165, 375 (1986).CrossRefGoogle Scholar
26Cabrera, A. L., J. Vac. Sci. Technol. A 8 (4), 3229 (1990).CrossRefGoogle Scholar
27Cabrera, A. L., J. Vac. Sci. Technol. A 11 (1), 205 (1993).CrossRefGoogle Scholar
28Cabrera, A. L., J. Chem. Phys. 93 (4), 2854 (1990).CrossRefGoogle Scholar
29Cabrera, A. L., Morales, E., Altamirano, L., and Espinoza, P., Rev. Mex. Fis. 39 (6), 932 (1993).Google Scholar
30Cabrera, A. L. and Kirner, J. F., Oxid. Metals 35 (5/6), 471 (1991).CrossRefGoogle Scholar
31Cabrera, A. L., Spencer, N. D., Kozak, E., Davis, P. W., and Somorjai, G. A., Rev. Sci. Instrum. 53, 1888 (1982).CrossRefGoogle Scholar
32Cabrera, A. L., Zehner, J. E., and Armor, J. N., Oxid. Metals 36 (3/4), 265 (1991).CrossRefGoogle Scholar