Structure analysis of supported disordered molybdenum oxides using pair distribution function analysis and automated cluster modelling

Troels Lindahl Christiansen, Emil T. S. Kjær, Anton Kovyakh, Morten L. Röderen, Martin Høj, Tom Vosch, Kirsten M. Ø. Jensen*

*Corresponding author for this work

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Abstract

Molybdenum oxides and sulfides on various low-cost high-surface-area supports are excellent catalysts for several industrially relevant reactions. The surface layer structure of these materials is, however, difficult to characterize due to small and disordered MoOit $sb x$ domains. Here, it is shown how X-ray total scattering can be applied to gain insights into the structure through differential pair distribution function (d-PDF) analysis, where the scattering signal from the support material is subtracted to obtain structural information on the supported structure. MoOx catalysts supported on alumina nanoparticles and on zeolites are investigated, and it is shown that the structure of the hydrated molybdenum oxide layer is closely related to that of disordered and polydisperse polyoxometalates. By analysing the PDFs with a large number of automatically generated cluster structures, which are constructed in an iterative manner from known polyoxometalate clusters, information is derived on the structural motifs in supported MoOx.
Original languageEnglish
JournalJournal of Applied Crystallography
Volume53
Issue number1
Pages (from-to)148-158
ISSN0021-8898
DOIs
Publication statusPublished - 2020

Keywords

  • Molybdenum oxides
  • Nanostructure
  • Pair distribution function analysis
  • Supported catalysts
  • Automated modelling

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