AVS 60th International Symposium and Exhibition
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS+AS+EN+SS-TuA

Paper NS+AS+EN+SS-TuA3
Oxygen Adsorption and Dissociation on Ag(110) and Au-Ag(110) Surfaces

Tuesday, October 29, 2013, 2:40 pm, Room 203 B

Session: Nanoscale Catalysis and Surface Chemistry
Presenter: M. Schmid, Harvard University
Authors: M. Schmid, Harvard University
J. Klobas, Harvard University
R.J. Madix, Harvard University
C.M. Friend, Harvard University
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We have investigated the adsorption and dissociation of molecular oxygen on thin film Au-Ag alloys because of their potential for selective oxidation catalysis. Our work is motivated by an interest in fundamental understanding of nanoporous gold catalysts, which are a dilute Au-Ag alloy, typically containing 3-10% Ag; nevertheless, this dilute alloy is active for O2 dissociation and for selective oxidation of CO and primary alcohols. We selected pure Ag(110) as a starting material because it strongly binds O2 by donation of substantial charge density into the O=O bond. This species undergoes competing desorption of O2 and dissociation to O atoms on the surface at ~170 K. We have investigated the effects of alloying with gold on the bonding and activity of O2 using a combination of Scanning Tunneling Microscopy (STM), Temperature Programmed Reaction Spectroscopy (TPRS), and X-ray Photoelectron Spectroscopy (XPS). There is a rich morphology that develops on the surface depending on the Au content, and a substantially different reactivity towards oxygen as compared to pure Ag and Au substrates. Further investigations of selective oxidation processes on this surface are also planned.