Different oxygen parameters of Fe~3O~4 which were reduced from α-Fe~2O~3 and γ-Fe~2O~3 with water-gas at 400℃ were observed by means of X-ray powder diffraction Rietveld structure refinement. Using bond-valence calculation method, the electrovalences of tetrahedra site A and octahedra site B of Fe~3O~4 reducing from γ-Fe~2O~3 are obviously different from that reducing from α-Fe~2O~3, but they can change into the normal ones after being aged at 600℃ in reducing atmosphere. There are also different in Mossbauer spectra of two types of Fe~3O~4. The first peak and Mossbauer spectrum of Fe~3O~4 reducing from α-Fe~2O~3 occurs splitting. The electrovalence changing directions of Fe deduced from the changes of isomer shift of A site and B site are the same as that bond-valence calculating method. A metastable Fe~3O~4 was obtained from γ-Fe~2O~3, having different electrovalence from normal Fe~3O~4 and having correlating with low-temperature catalytic activity of water-gas shift reaction.

Key words: CATALYST, IRON OXIDE, CATALYTIC ACTIVITY, MOSSBAUER SPECTROSCOPY