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1 2008

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Metal Dispersion and Alloy Homogeneity in Highly Dispersed Pt-Au/Al2O3 Catalysts

Yurkiv V., Legawiec-Jarzyna M., Juszczyk W., Kowalczyk Z., Karpiński Z.

Polish Journal of Chemistry

2008

Vol. 82, nr 9

1711-1711

Although hydrogen chemisorption performed in a pulse-flow system allows for a reliable determination of platinum dispersion in Pt/Al2O3 catalysts, it fails in the case when platinum is alloyed with gold. Much weaker hydrogen adsorption on mixed Pt-Au sites is not detected by this method which measures only instantaneous irreversible chemisorption. On the other hand, the static chemisorption method givestrustworthy values of metal dispersion. So, a combination of these two methods (pulse-flow and static) probes effectively both the metal dispersion as well as the d gree of alloying in supported Pt-Au catalysts. Obtained characterization data for the series of Pt-Au/Al2O3 catalysts prepared by incipient wetness impregnaion suggest that in this case Pt and Au remain intimately mixed in the form of Pt–Au bimetallic particles.