1H, 51V and 15N nuclear magnetic resonance studies of structure and properties of vanadia supported on TiO chi/SiO2.
1H magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra of TiO chi/SiO2 catalysts suggest the interaction of surface TiO chi species with Si-OH groups of the silica. Simultaneously, Ti-OH groups from surface titania species appear. The distribution of TiO chi species over SiO2 is non-uniform, since a considerable part of surface OH groups remains unreacted with supported titania. Supported vanadia species interact both with Si-OH and Ti-OH groups. 51V NMR spectra suggest the interaction of vanadia with supported titania species and show the non-uniform distribution of titania over the SiO2 surface. Deposition of titania as well as vanadia produces strong electron-accepting (Lewis) sites which interact with the terminal N atom of adsorbed N2O molecules, resulting in a downfield shift of the resonance in 15N NMR spectra. The acid strength of electron-accepting sites is similar in both cases. Only about 10% of the total amount of supported titania and vanadia create Lewis sites.
Mastikhin
V M
VM
Boreskov Institute of Catalysis, Novosibirsk, Russia.
Terskikh
V V
VV
Lapina
O B
OB
Filimonova
S V
SV
Seidl
M
M
Knözinger
H
H
D000327:Adsorption; D002384:Catalysis; D004579:Electron Transport; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009587:Nitrogen Isotopes; D011522:Protons; D012822:Silicon Dioxide; D013329:Structure-Activity Relationship; D014025:Titanium; D014639:Vanadium
D009587:Nitrogen Isotopes; D011522:Protons; D014639:Vanadium; C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium