SOLID-STATE REACTION IN THE IRON-MOLYBDENUM-ANTIMONY OXIDE SYSTEM

This work deals with the evolution of a mechanical mixture of Fe2(MoO4 )3 and alpha-Sb2O4 (prepared separately) during calcination in air at 500-degrees-C over a period of six days. The samples were studied by X -ray diffraction, X-ray photoelectron spectroscopy, BET surface area, CTEM, analytical electron microscopy and selected area electron diffra ction. A reaction occurs between the two phases, leading to a mixture of Fe2 (MoO4)3, Sb2O4, FeSbO4 and MoO3 with a significant increase of the surface area. Taking into account previous results, the present wo rk suggests that the ability of alpha-Sb2O4 to produce oxygen spillove r facilitates the oxidation of Sb3+ to Sb5+ allowing the solid state t ransformation to FeSbO4 to take place.