Effect of vanadium loadings in the textural and structural properties of Mg–Al–V mixed oxides

The synthesis of magnesium–aluminum oxides by precipitation method was carried out and the resulted powders were modified at the surface by addition of ammonium metavanadate by impregnation, in order to obtain 5, 10, 15, 20, and 30% of VO₃. After calcination, the resulting powders were characterized by physisorption of N₂, X-ray diffraction, Fourier Transform Infrared spectroscopy, Raman spectroscopy, and Temperature Programmed Reduction. The samples with 5- and 10-wt.% vanadia content exhibited the larger textural properties, while samples with higher vanadium loading possessed lower surface area, pore volume, and mean pore diameter; the later samples required higher temperatures to reduce them during TPR characterization, because the formation of crystals of detectable size by XRD. The prevailing detected vanadium species were VO₃ and V₂O₅ established by XRD, FTIR, and Raman spectra, while it was found by the absence of undesirable V=O in samples.