AVS 53rd International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM11
Pinpointing where CO Molecules Reside and React on Stepped Surfaces

Wednesday, November 15, 2006, 11:20 am, Room 2002

Session: Reactions on Metal & Bimetallic Surfaces
Presenter: J.N. Andersen, Lund University, Sweden
Authors: J.N. Andersen, Lund University, Sweden
A. Resta, Lund University, Sweden
E. Lundgren, Lund University, Sweden
A. Mikkelsen, Lund University, Sweden
Correspondent: Click to Email
The geometrical as well as the electronic structure in the vicinity of steps differs from that on the flat parts of the surface. These differences often significantly influence the adsorption of and reactions amongst adsorbate molecules and atoms. As small particles used for instance in catalysis has a high concentration of steps, step induced reactions may be dominant for such particles. In the present contribution we demonstrate that the C1s binding energy as measured by high resolution core level spectroscopy (HRCLS) can be used to pinpoint if CO molecules are adsorbed at steps on a number of vicinal surfaces and discuss why this is so. We give a number of examples of how this can be utilized for obtaining information related to the CO adsorption and to oxidation reactions of the CO molecules. We demonstrate how HRCLS measurements on a Pt(332) surface in thermodynamic equilibrium with an in-situ CO background pressure directly demonstrate a higher CO adsorption energy at the steps. Measurements from different vicinal Rh surfaces show that the specific facet present at the steps has a significant influence on the adsorption sites taken by CO molecules on the terraces at higher CO coverage. Finally, we show that this methodology allows pinpointing that oxidation of CO on a vicinal Pt(332) surface proceeds via the reaction with a 1D oxide exclusively found at the steps.