Characterization of Silica-Supported Tungsten Bis- and Tris-hydrides by Advanced Solid-State NMR

Wiebke Wackerow, Zeynabou Thiam, Edy Abou-Hamad, Walid Almaksoud, Mohamed N. Hedhili, Jean-Marie Basset

Research output: Contribution to journalArticlepeer-review

Abstract

Tungsten-hydrides supported on oxide supports are unique catalysts regarding the direct transformation of ethylene to propylene, alkane metathesis, and the low-temperature hydrogenolysis of waxes to lower molecular paraffins. The number of hydrides coordinated to the tungsten center and their structure on the siliceous support with very high surface silica (KCC-1) is unknown. KCC-1(700) silica of extremely high surface area allows for a high tungsten metal loading of 14 wt %. We show here the full characterization of supported tungsten bis- and tris-hydrides, which, after reaction with N2O gas, yield well-defined tungsten bis- and tris-hydroxide species on KCC-1(700). The obtained tungsten-hydroxide species are perfectly suitable for a detailed NMR study. The obtained tungsten hydroxo complexes are proven to be a tungsten bis-hydroxo and tungsten tris-hydroxo species. This analysis supports the conclusion that supported tungsten-hydride complexes coexist on the support as bis-hydride and tris-hydride species. They are, respectively, in close proximity to the silicon bis-hydride and the silicon mono-hydride. This proximity is explained by the mechanism of the formation of tungsten-hydride on the silica surface.
Original languageEnglish (US)
JournalThe Journal of Physical Chemistry C
DOIs
StatePublished - Jun 3 2021

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials

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