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).