摘要
采用XRD,XPS,Mossbauer和TPR-XRD技术考察了侵渍型负载铁HZSM-5 沸石催化剂的还原作用,结果表明:浸渍型载铁沸石焙烧后,铁主要以α-Fe_2O_3形态存在于沸石表面。500℃还原后,其还原度与载铁量及沸石硅铝比有关,其还原度可大于80％,粒度在11～13nm左右,还原过程中,出现三个TPR峰,分别相应于过程中的Fe^(3+)→Fe_3O_4→FeO→α-Fe^0三个阶段,各阶段的特征温度依次为;633K,723～773K,953～963K。
The reduction of the impregnated Fe/HZSM-5 zeolite has been studied by XPS, XRD, Mossbauer and TPR-XRD. It was shown that after calcination the iron on the surface of Fe/ZSM-5 zeolite was mainly α-Fe2O3. After reduction at 500℃, the reducibility of iron was relevant to the amount of supported iron and the Si/Al ratio of the zeolite, the reducibility was 80% or higher, and the particle size was ca. 11-13nm. During reduction, three peaks appeared in TPR spectra corresponding to Fe3+→Fe3O4→FeO→α-Fe°, and the characteristic temperature of each stage was 633K, 723-773K and 953-963K respectively.
基金
国家自然科学基金
