Characterization of Silica-Supported Tungsten Bis- and Tris-hydrides by Advanced Solid-State NMR
Hedhili, Mohamed N.
KAUST DepartmentChemical Science Program
Physical Science and Engineering (PSE) Division
Imaging and Characterization Core Lab
KAUST Catalysis Center (KCC)
KAUST Grant NumberBAS/1/1326-01-01.
Online Publication Date2021-06-03
Print Publication Date2021-06-17
Embargo End Date2022-06-03
Permanent link to this recordhttp://hdl.handle.net/10754/669399
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AbstractTungsten-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.
CitationWackerow, W., Thiam, Z., Abou-Hamad, E., Al Maksoud, W., Hedhili, M. N., & Basset, J.-M. (2021). Characterization of Silica-Supported Tungsten Bis- and Tris-hydrides by Advanced Solid-State NMR. The Journal of Physical Chemistry C. doi:10.1021/acs.jpcc.1c03625
SponsorsWe would like to acknowledge King Abdullah University of Science and Technology for funding. We also acknowledge KAUST NMR core lab for their continuous help. We acknowledge as well the KAUST Imaging Core Lab, particularly Dr. Alessandro Genovese.
King Abdullah University of Science and Technology: BAS/1/1326-01-01.
PublisherAmerican Chemical Society (ACS)