The Structure and Activity of Silica-Supported Palladium-Cobalt Alloys I. Alloy Homogeneity, Surface Composition, and Activity for Neopentane Conversion

W. Juszczyk, Z. Karpinski, D. Lomot, J. Pielaszek, Z. Paál, A. Y. Stakheev

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Chemisorption of H2 and CO, temperature-programmed reduction (TPR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and neopentane conversion show that differences in preparation method and overall metal loading lead to the formation of different Pd-Co bimetallic materials (changes in reducibility, metal particle size, and lateral homogeneity). Well-homogenized Pd-Co particles exhibit a very pronounced minimum in the plot of catalytic activity versus Pd-Co alloy composition. At the same time, a maximum exists in the isomerization selectivity vs the alloy composition. These deviations from the catalytic behavior of physical mixtures of the monometallic (Pd and Co) catalysts provide a basis for the estimation of how two metals interact with each other in a supported catalyst. Incipient wetness impregnation of silica by considerable amounts (10 wt%) of metal salts leads to the formation of catalyst precursors which are fully reduced at 380°C yielding good dispersion and lateral homogeneity. Chemisorption and in situ XRD studies are compatible with the kinetic investigations, but information on metal interaction by these methods is less clear. For high metal-loaded Pd-Co/SiO, catalysts, comparison of H2 chemisorption and XRD data suggests surface enrichment in palladium, which is confirmed by XPS.

Original languageEnglish
Pages (from-to)617-629
Number of pages13
JournalJournal of Catalysis
Volume142
Issue number2
DOIs
Publication statusPublished - Aug 1993

Fingerprint

Palladium alloys
palladium alloys
neopentane
cobalt alloys
Cobalt alloys
Surface structure
Silicon Dioxide
homogeneity
Metals
Silica
silicon dioxide
chemisorption
Chemisorption
catalysts
metals
x rays
X ray diffraction
Catalysts
diffraction
photoelectron spectroscopy

ASJC Scopus subject areas

  • Process Chemistry and Technology
  • Catalysis

Cite this

The Structure and Activity of Silica-Supported Palladium-Cobalt Alloys I. Alloy Homogeneity, Surface Composition, and Activity for Neopentane Conversion. / Juszczyk, W.; Karpinski, Z.; Lomot, D.; Pielaszek, J.; Paál, Z.; Stakheev, A. Y.

In: Journal of Catalysis, Vol. 142, No. 2, 08.1993, p. 617-629.

Research output: Contribution to journalArticle

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