Studies of architecture of MoO3–TiO2 catalysts

Abstract

X-Ray diffraction, F.t.i.r., scanning electron microscopy (SEM) and ion-scattering spectroscopy (ISS) have been applied to characterize a series of MoO3–TiO2(anatase) samples prepared by the grafting and impregnation methods. The sample prepared with the grafting method exhibits good dispersion of MoO3, whereas the impregnation technique leads to a poorer dispersion of molybdena on the surface of titania. The poorer dispersion of MoO3 is due to the clustering of molybdena when the MoO3 loading does not exceed the theoretical monolayer coverage (6.3 wt% MoO3). At higher MoO3 loading, crystals of MoO3 of morphology different from pure MoO3 crystals, appear. A possible explanation of this phenomenon is discussed.