Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-12-04T10:53:50.135Z Has data issue: false hasContentIssue false

The Role of Effective Rate Constants in Interfacial Kinetics

Published online by Cambridge University Press:  10 February 2011

Joachim Maier*
Affiliation:
Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany, weiglein@chemix.mpistuttgart.mpg.de
Get access

Abstract

A brief excerpt of a more comprehensive quantitative theoretical analysis on the role of effective rate constants in interfacial processes is given (in particular [1], see also [2,3]). Chemical incorporation, tracer incorporation and steady state electrical experiments are considered. It is shown that besides experimental differences there are mechanistic and conceptual differences between the three effective rate constants (kδ, k*, Qq). The treatment based on irreversible thermodynamics and chemical kinetics shows similarities and differences with respect to the analogous situation in the bulk. As special cases adsorption and transfer limited kinetics are considered. Having related the k-values to the exchange rates of the rate determining step and to the chemical capacitance outside the boundary zone, the characteristic dependencies on controlling parameters and also the correlation with diffusion coefficients can be derived. This is done for electron-rich materials such as SOFC cathodes. A further point which is briefly mentioned in this context is the fact that flux constriction effects may lead to apparent surface rate constants. The role of space charges is briefly discussed for the case of grain boundary kinetics [4]. In electron-poor materials such as SrTiO3(Fe2O3) or Zr02(Y203) additional mechanistic differences should occur, since in the tracer case mechanisms are possible at the surfaces which do not have to involve electrons directly. Here also discrepancies with respect to electrical experiments are predicted (leading to a surface analogue of a Haven ratio). Some experimental results obtained with SrTiO3 are discussed in this context.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Maier, J., Solid State Ionics 112, 197 (1998).Google Scholar
2. Jamnik, J. and Maier, J., Ber. Bunsenges. Phys. Chem. 101 (1), 23 (1997).Google Scholar
3. Leonhardt, M., Fleig, J. and Maier, J., in preparation; M. Leonhardt, Ph D thesis Stuttgart, to be published; M. Leonhardt, J. Jamnik and J. Maier, to be published.Google Scholar
4. Kilner, J. A., DeSouza, R. A., Fullaxton, I. C., Solid State Ionics 86–88, 703 (1996); H. J. Bouwmeester, H. Kruidhof, A. J. Burggraaf, Solid State Ionics 72, 184 (1994).Google Scholar
5. Kawada, T., Masuda, K., Suzuki, J., Kaimai, A., Kawamura, K., Nigara, Y., Mizusaki, J., Yugami, H., Arashi, H., Sakai, N. and Yokokawa, H., Proc. llth Int. Conf. Solid State Ionics, Hawaii, 1997, in press; B. C. H. Steele, Solid State Ionics 75, 157 (1995); H. J. Bouwmeester, H. Kruidhof, A. J. Burggraaf, Solid State Ionics 72, 184 (1994).Google Scholar
6. Denk, I., Traub, U., Noll, F., and Maier, J., Ber. Bunsenges. Phys. Chem. 99 (6), 798 (1995); I. Denk, F. Noll and J. Maier, J. Am. Ceram. Soc. 80 (2), 279 (1997); I. Denk, J. Claus and J. Maier, J. Electrochem. Soc. 144 (10), 3526 (1997).Google Scholar
7. Wagner, C., Progress Solid State Chemistry, Vol. 6, edited by Reiss, H. (Pergamon Press, Oxford, 1971).Google Scholar
8. Heyne, L., in Solid Electrolytes, edited by Geller, S. (Springer-Verlag, Berlin, 1977) pp. 169221.Google Scholar
9. Maier, J., J. Am. Ceram. Soc. 76 (5), 12121232 (1993).Google Scholar
10. Maier, J., Solid State Phenomena 39–40, 35 (1994); J. Jamnik, J. Maier, in preparation.Google Scholar
11. Jamnik, J. and Maier, J., unpublished.Google Scholar
12. Leonhardt, M. and Maier, J., to be published.Google Scholar
13. Sasaki, K. and Maier, J., in preparation.Google Scholar