IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS1-ThP

Paper SS1-ThP10
LITD-FTMS Study of Dehydrogenation of Cyclohexane on Al@sub 2@O@sub 3@-supported Pt Clusters

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Catalysis on Model Systems Poster Session
Presenter: M.M. Ivey, University of California, Irvine
Authors: M.M. Ivey, University of California, Irvine
M.F. Luo, University of California, Irvine
J.C. Hemminger, University of California, Irvine
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We present a study of the adsorption and subsequent thermally activated dehydrogenation of cyclohexane on oxide-supported Pt clusters by use of Fourier transform mass spectrometry (FTMS) in combination with laser-induced thermal desorption (LITD).@footnote 1@ Pt clusters were generated by thermal evaporation of Pt onto an Al@sub 2@O@sub 3@ ultra thin film of 10 Å thickness that was grown on a NiAl(001) surface through oxygen adsorption at high temperature.@footnote 2@ Both cyclohexane desorption and dehydrogenation are observed. The branching between the desorption and dehydrogenation paths was monitored using a combination of AES, TDS and LITD. The cyclohexane dehydrogenation on Pt clusters behaves in a manner significantly different from that on Pt(111) single crystal surfaces. We will show the reactivity/desorption behaviour for this system for a range of Pt surface loadings. This will be discussed in the light of the dependence on Pt average cluster size which was determined by an AES quantitative analysis of CO chemisorption, assuming hemispherical cluster shapes. @FootnoteText@ @footnote 1@ D.P. Land, C.L. Pettiette-Hall, J.C. Hemminger and R.T. McIver, Acc. Chem. Res. 24 (1991) 42. @footnote 2@ M.M. Ivey, H.C. Allen, A. Avoyan, K.A. Martin and J.C. Hemminger, J. Am. Chem. Soc. 120 (1998) 10980.