CHARACTERIZATION OF V2O5-ALPO4 CATALYSTS BY V-51 AND H-1 MAGIC-ANGLE-SPINNING SOLID-STATE NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY

Amorphous aluminum orthophosphate is used as a carrier for preparing a series of V2O5-AIPO(4) catalysts with varying vanadia content. The ca talysts were characterized by solid-state V-51 and H-1 magic-angle spi nning nuclear magnetic resonance (MAS NMR), electron spin resonance (E SR) and X-ray diffraction (XRD). The XRD patterns of the catalysts rem ained amorphous at all loadings studied. V-51 Solid-state NMR spectra revealed the presence of V2O5 microcrystallites at higher vanadia load ings. The H-1 MAS NMR spectra of the catalysts showed a maximum consum ption of support hydroxyl groups at 6 wt.-% V2O5 indicating the comple tion of a monolayer at this composition.