AVS 52nd International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM5
The Nature of Water on Oxygen Covered Pt: Low Temperature Activation and Unexpected Structure

Thursday, November 3, 2005, 9:40 am, Room 200

Session: Water-Surface Interactions
Presenter: T. Schiros, Stanford Synchrotron Radiation Laboratory
Authors: T. Schiros, Stanford Synchrotron Radiation Laboratory
H. Ogasawara, Stanford Synchrotron Radiation Laboratory
L.-Å. Näslund, Stockholm University, Sweden
M. Odelius, Stockholm University, Sweden
L.G.M. Pettersson, Stockholm University, Sweden
A. Nilsson, Stanford Synchrotron Radiation Laboratory
Correspondent: Click to Email
The nature of the adsorbed water layer on surfaces has been a topic of interest due to its relevance for many practical fields, including corrosion, electrochemistry, environmental science and heterogeneous catalysis. Recently the behavior of adsorbed water under the presence of oxygen has garnered increasing interest in connection to the triple phase boundaries problem in fuel cell catalysis. Here, we studied the co-adsorption of water and oxygen on Pt(111) with X-ray photoemission and X-ray absorption spectroscopy in an ultra high vacuum environment combined with electronic structure calculations in the frame work of density functional theory. While water absorbs intact on clean metal surfaces at low temperature,@footnote 1-3@ an oxidized Pt surface activates and splits adsorbed water even at low temperature. We propose a new structure model for the activated water on Pt(111). We find that the activated water aligns the molecular axis perpendicular to the surface and is hydrated in the equatorial plane. @FootnoteText@ @footnote 1@ H. Ogasawara et al, Phys. Rev. Lett. 89 (2002) 276102.@footnote 2@ K. Andersson et al, Phys. Rev. Lett. 93 (2004) 196101.@footnote 3@ K. Andersson et al, Surf. Sci. Lett. In press (2005). .