Fe助催Bi-Mo系催化剂复阻抗谱的研究

采用复阻抗频谱技术,研究Bi-Mo系丙烯选择氧化催化剂助催剂Fe的不同量与电导活化能和催化剂性能的关系。结果表明:当Fe/Bi小于4/6时,电导活化能由没加Fe时的485kJ/mol降于160kJ/mol.这时丙烯氧化为丙烯酸的选择性明显增加;Fe/Bi超过该限度后,电导活化能上升,选择性下降,此现象与体系中钼铁酸铋固溶体的形成和消失有关。

The Impedance Study for Bismuth-Molybdenum Catalysts System Promoting with Iron

With the complex impedance measurement technique, we studied the relationship between the conductivity activation energy and the catalytic characterization in bismuth molybdates for propytene seective Oxidation catalysts system, when doped with important iron promoter. The results showed that within certain limitation, the activation energy of conductivity decreases from 485 kJ/mol to 160 kJ/mol as the amounts of iron increase, while the selectivity of propylene to acrolein, increases, and when the amounts of iron exceed this limitation, the activation energy of conductivity increases, while the selectivity of propylene decreases. The X-ray diffraction and Raman Spectroscopy measurements also showed that this phenomenon is connected with the formation of iron-bismuth-molybdenum trinal solid solution.