A structural analysis of W–Sb mixed oxide catalyst

An investigation on the structure of W–Sb mixed oxide catalyst, W 12Sb x O y ( x = 1, 3, 5), is proposed. The W–Sb mixed oxide powders were prepared by the calcination of aqueous precursors, antimony tartrate and ammoniummetatungstate, and characterized with scanning electron microscope, X-ray diffractometer, and transmission electron microscope. At low content of Sb ( x = 1), the W–Sb mixed oxide powder consisted of polyhedral particles, and their crystal structure was triclinic WO 3. At higher content ( x = 3, 5), majority of the oxide powders were bar-shaped particles, consisting of triclinic WO 3 and tetragonal WO 3. With electron diffraction pattern and simulation, Sb incorporation into the cuboctahedral sites of perovskite-like WO 3 was proved and its effect on the phase transition from triclinic to tetragonal was discussed.