Study on the effects of Cr2O3 on the reduction behavior of γ-Fe2O3

XRD and TG reduction analysis show that gamma-Fe2O3 Fe-Cr catalysts, which contains 0.0 to 14.0 wt %. Cr2O3 and prepared by coprecipitating method, consist of crystalline gamma-Fe2O3 and non-crystalline Fe2O3. Between 150-450 degrees C, three reduction stages are observed in the catalyst. The first stage is non-crystalline Fe2O3 reduced to non-crystalline Fe3O4, the second is crystalline gamma-Fe2O3 to crystalline Fe3O4 and the third is non-crystalline Fe2O3 reduced to non-crystalline FeO. About 5 wt %. Cr2O3 can enter the lattices of gamma-Fe2O3 to form solid solution. With the increasing of Cr2O3 content, the relative abundance of non-crystalline Fe2O3 and the amount of soluble Cr2O3 in non-crystalline increases, while the crystalline size of gamma-Fe2O3 decreases. (C) 1999 Kluwer Academic Publishers.