High Zn/Al ratios enhance dehydrogenation vs hydrogen transfer reactions of Zn-ZSM-5 catalytic systems in methanol conversion to aromatics

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  • Irene Pinilla-Herrero, University of Oslo, Haldor Topsøe A/S
  • ,
  • Elisa Borfecchia, Haldor Topsøe A/S, University of Turin
  • ,
  • Julian Holzinger
  • ,
  • Uffe V. Mentzel, Haldor Topsøe A/S
  • ,
  • Finn Joensen, Haldor Topsøe A/S
  • ,
  • Kirill A. Lomachenko, European Synchrotron Radiation Facility
  • ,
  • Silvia Bordiga, University of Turin
  • ,
  • Carlo Lamberti, Southern Federal University, University of Turin
  • ,
  • Gloria Berlier, University of Turin
  • ,
  • Unni Olsbye, University of Oslo
  • ,
  • Stian Svelle, University of Oslo
  • ,
  • Jørgen Skibsted
  • Pablo Beato, Haldor Topsøe A/S
Abstract Two series of Zn-ZSM-5 catalysts were prepared by ion exchanging two commercial zeolites with different Si/Al ratios (40 and 15) with increasing Zn loadings. The nature of the Zn sites in the zeolite was studied by spectroscopy using laboratory and synchrotron techniques. All the evidences suggest that catalytic activity is associated with [Zn(H2O)n(OH)]+ species located in the exchange positions of the materials with little or no contribution of ZnO or metallic Zn. The effect of Zn/Al ratio on their catalytic performance in methanol conversion to aromatics has been investigated. In all cases, higher Zn content causes an increase in the yield of aromatics while keeping the production of alkanes low. For similar Zn contents, high densities of Al sites favour the hydrogen transfer reactions and alkane formation whereas in samples with low Al contents, and thus higher Zn/Al ratio, the dehydrogenation reactions in which molecular hydrogen is released are favoured.
Original languageEnglish
JournalJournal of Catalysis
Volume362
Pages (from-to)146-163
Number of pages18
ISSN0021-9517
DOIs
Publication statusPublished - Jun 2018

    Research areas

  • Zn-ZSM-5, Methanol to aromatics, Acidity, Zn sites, Ion exchange

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