AVS 47th International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuA

Paper SS1-TuA7
Alkylidenes on Molybdenum Carbide; Stable Carbenes on the Surface of a Catalytically Active Material

Tuesday, October 3, 2000, 4:00 pm, Room 208

Session: Mechanisms and Control of Surface Reactions
Presenter: P.H. McBreen, Laval University, Canada
Authors: E.M. Zahidi, Laval University, Canada
H. Oudghiri-Hassani, Laval University, Canada
P.H. McBreen, Laval University, Canada
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Molybdenum carbide competes well with platinum and ruthenium as a catalyst for various hydrocarbon transformation reactions. This reactive material can activate both CC and CH bonds. Yet, the present study shows that it is possible to form a layer of thermally stable carbenes on the carbide surface. Dissociative chemisorption of ketones leads to the formation of surface alkylidene groups which are stable to above 900 K. Extensive RAIRS, photoemission and XPS results will be used to describe the mechanism for the formation of these groups, and to outline their stability and their high temperature surface chemistry. This novel method for coupling relatively complex organic species to reactive surfaces may find application in the preparation of tailored catalysts, such as chiral modified systems. The observation of surface alkylidenes is also of direct interest for heterogeneous metathesis chemistry.