Study of supported PtCu and PdAu bimetallic nanoparticles using in-situ X-ray Tools

Sean M. Oxford, Peter L. Lee, Peter J. Chupas, Karena W. Chapman, Mayfair C. Kung, Harold H Kung

Research output: Contribution to journalArticle

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Abstract

A combination of two synchrotron X-ray techniques, X-ray absorption spectroscopy (XAS), and pair distribution function analysis (PDF) with complementary Fourier transform infrared (FTIR) spectroscopy measurement, was used to characterize the composition distributions of PdAu and PtCu bimetallic particles after treatment in H2 or CO and in the presence of these gases. This is the first reported application of PDF to the study of supported bimetallic nanoparticles. We found that XAS was informative in determining the component distribution of an initial sample, but PDF was better suited to following changes in the distribution upon changing the gas environment. Thus, the surface of a PtCu bimetallic particle of about 2.5 nm after treatment in H2 was found to be enriched in Cu, while the core was bimetallic. There was no evidence of a component-segregated core-shell structure. Treatment in CO caused enrichment of Pt to the surface layer, with a concomitant migration of Cu to the core. The average particle size remained the same. For the PdAu bimetallic particles, the surface and core compositions were similar after H2 treatment, and Pd was enriched in the surface after CO treatment. The X-ray results compared favorably to infrared spectroscopy results. The results demonstrated that the two X-ray techniques in combination can generate new information not available with either technique alone or other techniques, about the elemental distribution of bimetallic particles under conditions relevant to catalysis. They could provide new insight into structure-function relationships and time-on-stream behavior of bimetallic catalysts.

Original languageEnglish
Pages (from-to)17085-17091
Number of pages7
JournalJournal of Physical Chemistry C
Volume114
Issue number40
DOIs
Publication statusPublished - Oct 14 2010

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Carbon Monoxide
Nanoparticles
Distribution functions
X rays
nanoparticles
X ray absorption spectroscopy
distribution functions
x rays
Gases
absorption spectroscopy
infrared spectroscopy
Chemical analysis
Synchrotrons
Catalysis
Fourier transform infrared spectroscopy
Infrared spectroscopy
gases
Particle size
catalysis
surface layers

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Study of supported PtCu and PdAu bimetallic nanoparticles using in-situ X-ray Tools. / Oxford, Sean M.; Lee, Peter L.; Chupas, Peter J.; Chapman, Karena W.; Kung, Mayfair C.; Kung, Harold H.

In: Journal of Physical Chemistry C, Vol. 114, No. 40, 14.10.2010, p. 17085-17091.

Research output: Contribution to journalArticle

Oxford, Sean M. ; Lee, Peter L. ; Chupas, Peter J. ; Chapman, Karena W. ; Kung, Mayfair C. ; Kung, Harold H. / Study of supported PtCu and PdAu bimetallic nanoparticles using in-situ X-ray Tools. In: Journal of Physical Chemistry C. 2010 ; Vol. 114, No. 40. pp. 17085-17091.
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