Cu-Co-Fe催化剂的红外光谱研究

STUDIES OF Cu-Co-Fe CATALYSTS BY IR

本文用Perkin-Elmer FTIR 1710型红外光谱仪,对Cu-Co-Fe系合成混合醇催化剂进行研究。实验发现,催化剂在氧化态的物相分别以CuO、Co_3O_4和α-Fe_2O_3形式存在,这与X-射线衍射结果一致。由于组分间的相互作用,某些特征红外吸收峰有红移现象,CuO和α-Fe_2O_3的红外峰向低波数位移,使得Cu—O键和Fe—O键被削弱,因而催化剂更容易被还原。通过考察CO在还原态催化剂上的吸附行为,发现低温下CO吸附时,红外谱图上没有新的吸收峰;高温下吸附时在2135cm^(-1)和1745cm^(-1)附近存在有明显的吸收峰;前者归结为不可逆线式吸附,后者为桥式吸附结构;支持了在铁系催化剂上CO/H_2合成醇过程的链增长机理假设。铁组分的存在,有利于桥式结构的形式。

In this paper, the interaction among components of catalvsts is studied by IR technique. The structure of Cu-Co-Fe catalvsts has been investigated. It is found that the CuO、Co_3O_4 and α-Fe_2O_3 are verified in oxide state, the IR peaks of CuO and Fe_2O_3 are shifted towards to lower frequency, which results from the interaction of CuO and α-Fe_2O_3. The results of CO adsorption on the reduced catalvst indicate that no chemisorption peak of CO is observed at room temperature or 373K. There are two bands at 593K. The band at 2135cm^(-1) may be resulted from linear adsorption of CO. The other bands (1745cm^(-1), 1720cm^(-1) are assignated to bridge adsorption of CO, which are correlated with the present of iron component.