XPS study on the effects of treatments on Pt2+ and Co2+ exchanged into NaY zeolite

Zoltán Zsoldos, Gábor Vass, Gemnin Lu, László Guczi

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Abstract

X-ray photoelectron spectroscopy was applied to investigate Pt/NaY, Co/NaY and Pt-Co/NaY zeolites prepared by ion exchange (IE) and impregnation (IM). Changes in the electronic states and surface distribution of sodium and silicon were followed in NaY and in Pt and Co containing NaY in the as prepared (AP), calcined (OX) and reduced (RE) states. Decoration of the zeolite surface by alumina detected, is attributed to the local processes during ion exchange. Introduction of Co2+ ions into the Pt-containing samples influences the electronic states of platinum both in calcined and reduced state. Pt° facilitates reduction of Co2+ ions and formation of bimetallic Pt-Co particles within the zeolite supercages could also be evidenced. The results support earlier TPR measurements indicating the presence of very small Pt-Co bimetallic particles for (IE) samples. On the other hand, in the impregnated NaY no sodium exchange occurs and the transition-metal species are located at the external surface of NaY zeolites.

Original languageEnglish
Pages (from-to)467-475
Number of pages9
JournalApplied Surface Science
Volume78
Issue number4
DOIs
Publication statusPublished - Aug 1994

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ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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