Fritz-Haber-Institut / Chemical Physics |
|Formation of interface and surface oxides on supported Pd nanoparticles|
|Authors:||Schalow, Tobias; Brandt, Björn; Laurin, Mathias; Schauermann, Swetlana; Guimond, Sebastien; Kuhlenbeck, Helmut; Libuda, Jörg; Freund, Hans-Joachim|
|Date of Publication (YYYY-MM-DD):||2006-06-15|
|Title of Journal:||Surface Science|
|Journal Abbrev.:||Surf. Sci.|
|Issue / Number:||12|
|Copyright:||© 2006 Elsevier B.V. All rights reserved|
|Abstract / Description:||We have quantitatively studied the interaction between oxygen and an Fe3O4-supported Pd model catalyst by molecular beam (MB) methods, time resolved IR reflection absorption spectroscopy (TR-IRAS) and photoelectron spectroscopy (PES) using synchrotron radiation. The well-shaped Pd particles were prepared in situ by metal evaporation and growth under ultrahigh vacuum (UHV) conditions on a well-ordered Fe3O4 film on Pt(1 1 1).
It is found that for oxidation temperatures up to 450 K oxygen predominantly chemisorbs on metallic Pd whereas at 500 K and above (10−6 mbar effective oxygen pressure) large amounts of Pd oxide are formed. These Pd oxide species preferentially form a thin layer at the particle/support interface, stabilized by the iron-oxide support. Their formation and reduction is fully reversible. Upon decomposition, oxygen is released which migrates back onto the metallic part of the Pd surface. In consequence, the Pd interface oxide layer acts as an oxygen reservoir, the capacity of which by far exceeds the amount of chemisorbed oxygen on the metallic surface.
|Free Keywords:||Palladium; Iron-oxide; Oxidation; Surface oxide; CO; Model catalyst; Molecular beam; IR reflection absorption spectroscopy; Photoelectron spectroscopy|
|External Publication Status:||published|
|Communicated by:||Hans-Joachim Freund|
|Affiliations:||Fritz-Haber-Institut/Chemical Physics/Molecular Beam|
Fritz-Haber-Institut/Chemical Physics/Spectroscopy / Spectro-Microscopy
Fritz-Haber-Institut/Chemical Physics/Chemical Physics
|External Affiliations:||Libuda J, Corresponding author. Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße 3, D-91058 Erlangen, Germany|
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