THE RELATIONSHIP BETWEEN XRD MICROSTRUCTU RE CHARACTERISTIC AND CATALYTIC ACTIVITY OF FE3O4

In this study we investigated the microstructure characteristic of Fe3 O4 water-gas shift catalyst prepared by different crystalline forms of Fe2O3 with the method of line-profile analysis based on the Voigt fun ction. We found a relationship which exists between the lattice distor tions of Fe3O4 and their catalytid activities. Fe3O4 reduced from gamm a-Fe2O3 has larger lattice distortion than that from alpha-Fe(2)O3. At the temperature of 325 degrees C, the conversion percentage of water- gas shift catalyst of Fe3O4 reduced from gamma-Fe2O3 is 30% higher tha n that of Fe3O(4) reduced from alpha-Fe2O3. Under industrial reacting conditions, such a distortion structure can keep stable for a long tim e. However, after being aged at 600 degrees C for 2h, its distortion a nd low temperature activity obviously decreases. The various wet-metho ds are important technique to obtain high activity water-gas shift cat alyst. But only gamma-Fe2O3 which is analogy to Fe3O4 in structure can keep its high activity state during reduction process.