AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM5
Coverage Dependent Selectivity and a New Approach to Tayloring Nanostructures on Single Crystal Surfaces

Wednesday, October 4, 2000, 9:40 am, Room 208

Session: Chemical Interactions and Surface Reactivity
Presenter: A.V. Teplyakov, University of Delaware
Authors: A.V. Teplyakov, University of Delaware
H. He, University of Delaware
A.T. Mathauser, University of Delaware
Correspondent: Click to Email
Here we report a remarkable chemistry exhibited by 6-bromo-1-hexene on a Cu@sub 3@Pt(111) surface. The dehydrocyclization reaction leading to the formation of benzene takes place at very low coverage; as the surface fills up the decomposition becomes a predominant pathway. Similar behavior was reported for other linear hydrocarbons on metals and metal alloys previously. However, further increase of surface concentration of 6-bromo-1-hexene leads to a different type of chemistry. The hydrogenation of 5-hexenyl produced as a result of C-Br bond dissociation leads to the formation of 1-hexene which is stable on a surface until the molecular desorption of this compound starts at 230 K. Molecular desorption from the monolayer becomes significant at even higher dose. All these processes occur within a specific coverage very cleanly making the 6-bromo-1-hexene on a Cu@sub 3@Pt(111) surface extremely attractive to analyze the kinetics of coverage dependent processes. Steric requirements for each of the processes described here and the availability of the adsorption sites on the alloy surface are believed to govern the predominant reaction. Thermodynamics and potential applications of these chemical processes for masking and production of nanoscale features will be discussed.