Synthesis and characterization of supported vanadium oxides by adsorption of the acetylacetonate complex

Abstract

Supported vanadium oxide catalysts are prepared by adsorption and calcination of vanadium acetylacetonate complexes on the surfaces of silica and alumina. The interaction of the complex with the support is studied by FTIR, XRD, TGA and chemical analysis. The synthesis parameters are optimized in order to obtain a well dispersed layer on the surface. After calcination, the acetylacetonate complexes decompose and form a surface layer of VO_x species. These surfaces have been studied with ⁵¹V NMR, UV–VIS diffuse reflectance and XRD spectroscopies. The method of acetylacetonate adsorption on silica enables the creation of supported VO_x catalysts with a V loading of 0.5 mmol g^–1(2.5 wt.% V), with all species in a strictly tetrahedral configuration and no formation of microcrystallites. On the alumina surface, vanadium loadings that are 5 times higher can be achieved without induced crystallinity.