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The reactivity of gold and platinum metals in their cluster phase

  • U. Heiz
  • A. Sanchez
  • S. Abbet
  • W.-D. Schneider
Conference paper

Abstract

Platinum surfaces are known to he among the moss active ones for the oxidation of carbon monoxide, whereas gold surfaces are completely inert for this reacticsr. The question remains: Do small clusters of these two metals maintain these distinct differences? To answer this question, we have employed temperature-programmed reaction (TPR) and Fourier transform infrared (FTIR,) spectroscopy to investigate the reactivity of small platinum and gold clusters consisting of up to 20 atoms. These dusters are generated in the gas phase by a laser evaporation source and, after mass selection, are deposited with low kinetic energy onto thin MgO films. The oxidation of CO is studied for the octamer and the icosamer under UHV conditions. Surprisingly; all investigated cluster sizes are catalytically active. Pt20 shows the highest reactivity and oxidizes almost 6 CO molecules, whereas Pt8, Au20, and Aus oxidize just one CO molecule under identical experimental conditions.

PACS

36.40.Jn Reactivity of clusters 82.65.Jv Heterogeneous catalysis at surfaces 82.80.Ch Ultraviolet, visible, infrared, Raman, microwave, and magnetic resonance spectroscopic analysis methods, spectrophotometry; colorimetry 

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Copyright information

© Springer-Verlag Italia 1999

Authors and Affiliations

  • U. Heiz
    • 1
  • A. Sanchez
    • 1
  • S. Abbet
    • 1
  • W.-D. Schneider
    • 1
  1. 1.Institut de Physique de hi Matière CondenséeUniversité de LausanneLausanneSwitzerland

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