ISSN:
1572-879X
Schlagwort(e):
tungsten heteropoly acids
;
determination of proton sites
;
heteropoly acids supported on carbon
;
31P29Si and17O MAS NMR
;
FT-IR
;
XRD
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract 17O MAS NMR spectra for solid heteropoly acid (HPA) H3PW12O40 are reported. Comparison of solid-state and solution17O resonances shows that in the solid dehydrated H3PW12O40 terminal W=O oxygen atoms are the predominant protonation sites. H3PW12O40 and H4SiW12O40 supported on chemically activated carbon have been studied by means of NMR, FT-IR and XRD. The carbon-supported HPA's retain their Keggin structure and form finely dispersed HPA species. No HPA crystal phase is developed even at an HPA loading as high as 45 wt%.31P,29Si and17O MAS NMR spectra for bulk and carbon-supported HPA's indicate interaction of the HPA Keggin units with the carbon surface, causing large line broadening in the NMR spectra.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00806992
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