Nuclear magnetic resonance study of Pt-Rh bimetallic clusters

Zhiyne Wang, Jean Philippe Ansermet, Charles P. Slichter, J. H. Sinfelt

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The use of pulsed nuclear magnetic resonance to study supported Pt-Rh bimetallic clusters is described. Using energy-dispersive spectroscopy it has been shown that each individual cluster contains both Pt and Rh. For lower-dispersion samples (larger metal particles) the centre of the particles is pure Pt. For higher-dispersion samples (smaller metal particles) the Pt concentration in the surface layer of the clusters has been measured from observation of the dependence of the height of the Pt spin echo on the time, τ, between pulses of the echo sequence. For clusters on which 13CO has been adsorbed, the 13CO resonance frequency varies with the Pt-Rh ratio. 195Pt-13C spin-echo double resonance (SEDOR) has been employed to measure the fraction of Pt atoms in the surface layer of the cluster. By studying how the SEDOR signal depends on the frequency of the 13CO exciting pulse, it has been shown that the resonance frequency of 13CO is independent of whether the CO is bonded to Pt or Rh in a given sample. This result shows that the frequency shift of the 13CO is a non-local rather than a local phenomenon. The 13CO shift corresponds to that of pure Rh particles, even for surfaces which contain a substantial Pt content. The significance of this result is explained in terms of the mixing of the molecular and metallic wave-functions.

Original languageEnglish (US)
Pages (from-to)3785-3802
Number of pages18
JournalJournal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
Volume84
Issue number11
DOIs
StatePublished - 1988

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metal particles
Metals
Nuclear magnetic resonance
echoes
nuclear magnetic resonance
surface layers
Carbon Monoxide
Wave functions
Energy dispersive spectroscopy
pulses
frequency shift
Atoms
wave functions
shift
spectroscopy
atoms
energy

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Nuclear magnetic resonance study of Pt-Rh bimetallic clusters. / Wang, Zhiyne; Ansermet, Jean Philippe; Slichter, Charles P.; Sinfelt, J. H.

In: Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases, Vol. 84, No. 11, 1988, p. 3785-3802.

Research output: Contribution to journalArticle

Wang, Zhiyne ; Ansermet, Jean Philippe ; Slichter, Charles P. ; Sinfelt, J. H. / Nuclear magnetic resonance study of Pt-Rh bimetallic clusters. In: Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases. 1988 ; Vol. 84, No. 11. pp. 3785-3802.
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