CHARACTERIZATION OF ALPO SYSTEMS, PRECURSORS OF THE NOVEL BASIC CATALYST FAMILY ALPON

XPS and DRIFTS (diffuse reflectance infrared spectroscopy) spectra of AlPO systems, formally AlPO4-Al2O3, obtained by the sol-gel method hav e been studied in order to understand their geometric and electronic s tructure. Both DRIFTS and XPS demonstrate that the acid-base character of these samples depends on a structural modification. For low phosph orus content an amorphous spinel-like solid is proposed. This geometri c arrangement alters the electronic density of oxide ions and phosphor us cations and hence their Lewis acid-base properties with respect to the amorphous solid having aluminium and phosphorus only in tetrahedra l arrangement.