AVS 51st International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM8
Interaction of CO, Au, and O on Ru(0001)

Thursday, November 18, 2004, 10:40 am, Room 210B

Session: Metal Oxide and Clusters III: Supported Cluster Formation and Reactivity
Presenter: Q. Wu, Brookhaven National Laboratory
Authors: Q. Wu, Brookhaven National Laboratory
J. Hrbek, Brookhaven National Laboratory
Correspondent: Click to Email
The coadsorption of O, Au, and CO is studied on the Ru(0001) surface using temperature programmed desorption, Auger electron spectroscopy, and low energy electron diffraction. For low oxygen coverage (O(2x1) or @theta@@sub O@ = 0.5 ML), Au is found to compress the surface oxygen, and contributes to two first-order-like desorption peaks of O@sub 2@ (e.g. ~1150K and ~1200K). The double-peak structure of O@sub 2@ desorption is also observed when Au compresses the "O-rich" Ru(0001) surface (O(1x1) or @theta@@sub O@ ~1 ML excluding subsurface oxygen); the desorption of subsurface oxygen occurs at ~1050K. Desorption is a dynamic process: after subsurface O desorption, compressed surface oxygen starts to desorb and gold spreads on the Ru surface. Au desorption (0.5 ML to 5 ML) from the oxygen modified Ru surface (both O(2x1) and O(1x1)) is consistent with the presence of 3D Au islands. The majority of CO coadsorbed on Au/O/Ru(0001) surface desorbs at low temperatures around 200K; a small fraction reacts with the compressed oxygen to form CO@sub 2@ that desorbs at ~300K.