Topics in Catalysis

, Volume 10, Issue 3, pp 157–165

An atomic X-ray absorption fine structure study of the influence of hydrogen chemisorption and support on the electronic structure of supported Pt particles

  • D.E. Ramaker
  • G.E. van Dorssen
  • B.L. Mojet
  • D.C. Koningsberger
Article

DOI: 10.1023/A:1019157327060

Cite this article as:
Ramaker, D., van Dorssen, G., Mojet, B. et al. Topics in Catalysis (2000) 10: 157. doi:10.1023/A:1019157327060

Abstract

The physical principles of atomic XAFS (AXAFS) are presented along with important details on how to isolate the AXAFS contribution from the experimental XAFS data. Intuitive illustrations are given showing how various interactions of the absorber atom with its neighbours influence the AXAFS contribution. Hydrogen chemisorbed on the surface of the supported metal particles is shown to have a strong influence on the amplitude of the Fourier transform AXAFS peak. The effect of the support (with different amounts and types of charge compensating ions (H+, K+), different Si/Al ratio and extra-framework Al) on the experimental AXAFS spectra of Pt dispersed in zeolites (LTL,Y) and on flat supports (Al2O3–SiO2, MgO–Al2O3) are summarised. It is shown that the essence of the metal–support interaction, as revealed in the AXAFS, is a shift in the ionisation potential of the valence d-orbital electrons brought about by the polarisation induced primarily by the changing charge on the support oxygen atoms.

atomic XAFS spectroscopysupported platinum catalystsmetal–support interactionPt electronic structurehydrogen chemisorptionparticle size effects

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • D.E. Ramaker
    • 1
  • G.E. van Dorssen
    • 2
  • B.L. Mojet
    • 2
  • D.C. Koningsberger
    • 2
  1. 1.Department of Chemistry and Materials Science InstituteGeorge Washington UniversityUSA
  2. 2.Department of Inorganic Chemistry and CatalysisDebye Institute, Utrecht UniversityUtrechtThe Netherlands