Structure and catalytic activity of Co-based bimetallic systems in NaY zeolite: Low temperature methane activation

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Dissociative chemisorption of methane over cobalt, platinum, ruthenium particles and over their bimetallic combinations inserted into NaY by ion exchange, as well as sequential hydrogenation of the CHx species formed have been investigated. Temperature programmed reduction (TPR), X-ray diffraction (TRD), X-ray photoelectron spectroscopy (XPS) and CO chemisorption indicated that reduction of Co2+ ions in Co/NaY can significantly be facilitated by the presence of platinum and ruthenium. In Co-Pt/NaY bimetallic Co-Pt particles were formed, whereas in Co-Ru/NaY no direct evidence is available for the formation of Co-Ru bimetallic particles. It is established that Co/NaY sample modified by platinum and ruthenium exhibits a superior behavior in methane activation and in its sequential hydrogenation to higher hydrocarbon. This is interpreted by two factors: (i) enhanced reduction of cobalt and (ii) stabilization of small bimetallic particles inside the zeolite supercage. Calcination in oxygen promotes migration of ruthenium particles to the external surface, but in the case of cobalt-ruthenium bimetallic particles this process is hampered by cobalt. Nevertheless, in both systems a synergistic effect exists and the amount of CHx species considerably increase at the temperature lower than those applied for e.g. Co-Ru/Al2O3. For the formation of higher hydrocarbons the CHx surface species with a value of 1<x<2 is required.

Original languageEnglish
Pages (from-to)861-868
Number of pages8
JournalStudies in Surface Science and Catalysis
Volume105 B
Publication statusPublished - Jan 1 1997


ASJC Scopus subject areas

  • Catalysis
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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