摘要
由铁锰羰基簇混合制备的高分散Ｆｅ－Ｍｎ催化剂，对低碳烯烃来说，比簇衍生的铁催化剂表现出较高的ＣＯ加氢选择性，和较长的寿命。本文用Ｍｎ、Ｆｅ的Ｋ边ＸＡＮＥＳ谱研究了加入到铁体系中的锰组分的作用。结果表明，锰的存在不仅有利于提高铁分散度，而且也易于保持和恢复铁的零价特征。在催化剂的氧化还原过程中，观察到锰的价态在Ｍｎ（Ⅱ）－Ｍｎ（Ⅳ）－Ｍｎ（Ⅲ）间变化。在所有的过程中，没有观察到零价锰存在。
Highly dispersed Fe-Mn catalysts prepared from a mixed iron-manganese cluster has shown higher activity than that of cluster derived iron catalyst for the selective production of lower olefins in CO hydrogenation.A longer life is also observed.The features of the manganese added to iron are investigated in this work using Mn and Fe K-edge XANES.The results reveal that,by the addition of manganese, not only a higher iron dispersion is achieved,but also the zero-valent feature of the iron is easily maintained or recovered.The oxidation states of manganese is found to be changed from Mn(Ⅱ) to Mn(Ⅳ) and from Mn(Ⅳ) to Mn(Ⅲ) during oxidation and reduction of the catalyst.NO zero valent manganese is observed in all steps.
出处
《分子催化》
EI
CAS
CSCD
1996年第2期95-102,共8页
Journal of Molecular Catalysis(China)
