In this study we investigated the microstructure characteristic of Fe3O4 water-gas shift catalyst prepared by different crystalline forms of Fe2O3 with the method of line-profile analysis based on the Voigt function. We found a relationship which exists between the lattice distortions of Fe3O4 and their catalytic activities. Fe3O4 reduced from γ-Fe2O3 has larger lattice distortion than that from α-Fe2O3. At the temperature of 325℃, the conversion percentage of water-gas shift catalyst of Fe3O4 reduced from γ-Fe2O3 is 30% higher than that of Fe3O4 reduced from α-Fe2O3. Under industrial reacting conditions, such a distortion structure can keep stable for a long time. However, after being aged at 600℃ for 2h, its distortion and low temperature activity obviously decreases. The various wet-methods are important technique to obtain high activity water-gas shift catalyst. But only γ-Fe2O3 which is analogy to Fe3O4 in structure can keep its high activity state during reduction process.

Key words: X-RAY DIFFRACTION ANALYSIS, IRON OXIDE, WATER GAS, MICRO-STRUCTURE, CATALYTIC ACTIVITY