Characterization of V2O5-AlPO4 catalysts by 51V and 1H magic-angle spinning solid-state nuclear magnetic resonance spectroscopy

Abstract

Amorphous aluminum orthophosphate is used as a carrier for preparing a series of V2O5-AlPO4 catalysts with varying vanadia content. The catalysts were characterized by solid-state 51V and 1H magic-angle spinning nuclear magnetic resonance (MAS NMR), electron spin resonance (ESR) and X-ray diffraction (XRD). The XRD patterns of the catalysts remained amorphous at all loadings studied. 51V Solid-state NMR spectra revealed the presence of V2O5 microcrystallites at higher vanadia loadings. The 1H MAS NMR spectra of the catalysts showed a maximum consumption of support hydroxyl groups at 6 wt.-% V2O5 indicating the completion of a monolayer at this composition.