Fe-Mn/SiO_2催化剂的制备及其催化甲苯燃烧性能

以SiO2为载体,采用浸渍法分别制备了Fe-Mn(物质的量比为1∶1)质量分数为5%~35%的Fe-Mn/SiO2催化剂,以及Fe-Mn质量分数为30%,Fe-Mn物质的量比(x=0.1~0.9)的Fex-Mn1-x/SiO2催化剂,在常压固定床反应器上评价了这些催化剂对甲苯催化燃烧的反应性能,用X-射线衍射、氢气程序升温还原等分析手段对催化剂的结构进行了研究。结果表明Fe、Mn物质的量比为1∶1、Fe-Mn质量分数为30%的Fe-Mn/SiO2催化剂具有最好的活性,在280℃的反应条件下甲苯可完全催化燃烧。在Fe-Mn/SiO2催化剂体系中,Fe-Mn质量分数小于30%时检测不到Fe或Mn的物相。Fe-Mn质量分数大于30%时只检测到了Fe2O3物相;在Fex-Mn1-x/SiO2催化剂体系中,x的值在0.5~0.9之间时只检测到了Fe2O3物相,x的值在0.1~0.3之间时只检测到了Mn2O3物相。催化剂的氧化还原性能与Fe-Mn的质量分数和Fe、Mn的物质的量比有很大的关系,这些可能都影响着催化剂的性能。

Preparation of Fe-Mn/SiO_2 catalysts and their performance in the catalytic combustion of toluene

A series of Fe-Mn/SiO_2 catalysts with the Fe-Mn(1:1 ratio by amount of substance)loading ranging from 5% to 35%and 30%Fe_x-Mn_(1-x)/SiO_2(x=0.1-0.9)catalysts were prepared.The activities of the catalysts in the catalytic combustion of toluene were evaluated in a continuous flow reactor at atmosphere pressure.The struc-tures of the catalysts were investigated using XRD and H_2-TPR.The 30% Fe-Mn/SiO_2 catalyst showed the best cat-alytic performance for toluene combustion.The initial and complete combustion temperatures of catalytic toluene combustion were 250℃ and 280℃,respectively.For the Fe-Mn/SiO_2 catalysts,the Fe_2O_3 phase was observed when the loading of Fe-Mn was more than 30%.For the 30%Fe_x-Mn_(1-x)/SiO_2 catalysts,the Fe_2O_3 phase was ob-served when the value of x was in the range 0.5 to 0.9 whilst the Mn_2O_3 phase was observed when the value of x was in the range 0.1 to 0.3.The redox capabilities of the catalysts were found to depend on both the Fe-Mn content and the mass ratio of Fe to Mn.