The catalytic oxidation of propylene: V. X-ray characterization of iron-containing bismuth molybdate catalysts

Abstract

The effects on phase composition and structure of adding iron to bismuth molybdate catalysts were investigated by X-ray diffraction methods. Structural and phase transformations were observed to be functions of the calcination temperature and composition. In addition, ternary compounds containing bismuth, molybdenum, and iron were identified. These ternary compounds were formed when the calcination temperature was greater than 550 °C and were characterized by a monoclinic unit cell which was derived from and closely related to a scheelite unit cell. At calcination temperatures of 450 °C or less, a poorly crystallized compound with a scheelite structure was identified.