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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 mixture of iron manganese carbonyls exhibit higher CO hydrogenation selectivity and longer lifetime for lower olefins than cluster-derived iron catalysts. In this paper, Mn and Fe K-edge XANES spectra of the addition of iron to the system of manganese components. The results show that the presence of manganese is not only conducive to improving the iron dispersion, but also easy to maintain and restore zero-valent characteristics of iron. During the redox process of the catalyst, it was observed that the valence of manganese varied between Mn (II) -Mn (IV) -Mn (III). In all the process, zero-valent manganese was not observed.