AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP37
Reactivity of CO over Au Surfaces at Elevated Pressure

Wednesday, October 4, 2000, 11:00 am, Room Exhibit Hall C & D

Session: Poster Session
Presenter: K.F. Peters, European Synchrotron Radiation Facility, France
Authors: K.F. Peters, European Synchrotron Radiation Facility, France
P. Steadman, European Synchrotron Radiation Facility, France
O. Robach, European Synchrotron Radiation Facility, France
J. Alvarez, European Synchrotron Radiation Facility, France
S. Ferrer, European Synchrotron Radiation Facility, France
Correspondent: Click to Email
The "Pressure Gap" in surface science separates the well-studied UHV regime from the near-atmospheric pressure regime, where gas-phase catalysis is typically employed. We present first results from a new UHV/HiP surface x-ray diffraction chamber that is capable of spanning the pressure gap over 13 orders of magnitude up to 5 bars or higher.@footnote 1@ The UHV/HiP chamber is employed here to study gas-surface reactivity of carbon monoxide over metals. The Au(111) and Pt(111) surfaces are investigated because of their known inertness to carbon monoxide in vacuum studies. Moreover, CO/Pt(111) is an archetypal model of catalysis, whereas gold is among the most inert metals and is only known to adsorb CO at cryogenic temperatures. The observed gas-surface reactions are unexpectedly strong, owing to the elevated pressures. Both CO/Au(111) and CO/Pt(111) become reactive at near-atmospheric pressures and elevated temperatures. On Au(111), the Herringbone reconstruction can be lifted under certain conditions.@footnote 2,3@ The Pt(111) surface reacts with CO to form a new structure that has never previously been observed in vacuum studies. An important feature of these two examples is that the metal atoms are displaced significantly from their natural positions, which is uncommon in traditional examples of gas adsorption. @FootnoteText@ @footnote 1@P.Bernard, K.F.Peters, J.Alvarez, S.Ferrer, Rev.Sci.Instr., 70, 2, 1999, 1478-1480. @footnote 2@Steadman et al, accepted to Phys.Rev.B @Footnote 3@Peters et al, submitted.