Mössbauer Spectroscopy of Supported Bimetallic Catalysts
In recent years there has been renewed interest in catalysis by alloys from both the fundamental and practical points of view. Much of this interest has been stimulated by the advent of bimetallic catalysts in catalytic reforming. Recent studies of Sinfelt and co-workers (1) have demonstrated that alloying can have a marked effect on catalytic specificity. For example, the specific activity of bulk CuNi alloys for carbon-hydrogen bond breaking (dehydrogenation) is nearly independent of composition up to ~80 atomic percent Cu whereas the specific activity for carbon-carbon bond breaking (hydrogenolysis) is decreased by about four orders of magnitude when ~30 atomic percent Cu is added to Ni. Similar results obtained by Sinfelt (2) for SiO2-supported CuRu and CuOs catalysts strongly point to the formation of bimetallic clusters in these well-dispersed metal catalysts. The term bimetallic cluster is preferred to alloy for well-dispersed particles where surface effects dominate since catalytic evidence indicates that bimetallic clusters may be formed even for cases where no corresponding bulk alloy is known (2).
KeywordsIsomer Shift Quadrupole Splitting Bimetallic Catalyst Bulk Alloy Mossbauer Spectrum
Unable to display preview. Download preview PDF.
- 3.R. L. Garten, J. Catal., in press.Google Scholar
- 4.For example see J. R. Anderson, “Structure of Metallic Catalysts”, Academic Press, New York, 1975.Google Scholar
- 8.a) M. C. Hobson, Jr. and H. M. Gager, J. Colloid and Interface Sci., 34, 357 (1970). (b) H. M. Cager, J. F. Lefelhoez and M. C. Hobson, Jr., Chem. Phys. Lett., 23 386 (1973). (c) T. Tachibana, T. Ohya, T. Yoshioka, J. Koezuka and H. Ikoma, Bull. Chem. Soc. Japan, 42, 2180 (1969).Google Scholar
- 10.R. L. Garten, unpublished results.Google Scholar