Structure stabilizing effect of tungsten in mixed molybdenum oxides with Mo5O14-type structure

Bulk structural properties of single phase crystalline (Mo0.91V0.09)5O14 and (Mo0.68V0.23W0.09)5O14 materials were investigated using in situ X-ray diffraction and in situ X-ray absorption spectroscopy at three metal edges. Temperature programmed experiments in reducing (propene) and oxidizing (oxygen) atmosphere and isothermal redox experiments at 773 K revealed differences in the bulk properties of the two phases studied. A structure stabilizing effect of tungsten in (MoVW)5O14 under oxidizing conditions was found. Moreover, tungsten centers in a (MoVW) dioxide material exert a structure-directing effect towards re-oxidation to a Mo5O14-type structure.