Tuning of the acid-base properties of primary Me2O3 (Me = Al, Ga, In) and binary (ZrO2-Me2O3) (Me = B, Al, Ga, In) oxides by adding WO3: A calorimetric study

In this work two series of samples were prepared by impregnation of Me (Me = Al, Ga, In) hydroxides and Zr-Me (Me = B, Al, Ga, In) mixed hydroxides with an ammonium metatungstate hydrate solution followed by calcination at 400 °C. The obtained WO3/Me2O3 and WO3/(ZrO2-Me2O3) samples have been characterized in terms of their structural, textural, and surface properties, including the acid features, by a variety of techniques (BET, XRD, TG) and microcalorimetry. The acid-base properties were estimated by the adsorption of NH3 and SO2 as probe molecules, respectively. The prepared mixed oxide samples showed very different properties in terms of surface area and X-ray diffractograms. All obtained samples showed a specific acidic-basic character influenced by the relative amounts of each oxide, the most acidic samples being WO3/ZrO2 and WO3/Al2O3 and WO3/(Al2O3-ZrO2).