摘要
湿法工艺制备的不同晶型Fe_2O_3,经水煤气还原后Fe_3O_4的X射线衍射微结构特征,用分析微应变和晶粒尺寸的Voigt函数单峰分析法进行了测定Fe_3O_4微应变大小同催化活性间存在一种对应关系.γ-Fe_2O_3还原的Fe-3O_4比α型还原的有更大的晶格畸变,在325℃,500空速条件下,CO转化率达97%以上,比后者高出30%多,这种畸变结构在工业催化反应条件下能长期稳定,但经600℃高温处理后,畸变减小,活性下降.湿法工艺可以获得具有不同活性的Fe_3O_4前身,γ-Fe_2O_3与Fe_3O_4晶体结构上的类似,使它在还原过程中,能把这种高活性的结构状态保留下来.
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*-Fe2O3 which is analogy to Fe3O4 in structure can keep its high activity state during reduction process.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1995年第10期966-971,共6页
Acta Chimica Sinica
基金
浙江省自然科学基金资助的项目.
