物理化学学报 >> 1991, Vol. 7 >> Issue (01): 16-21.doi: 10.3866/PKU.WHXB19910103

研究论文 上一篇    下一篇

α-Fe2O3在Y沸石上的分散

杨雪敏; 章彬; 贺鹤勇; 高滋   

  1. 复旦大学化学系
  • 收稿日期:1989-07-19 修回日期:1990-02-01 发布日期:1991-02-15
  • 通讯作者: 高滋

Dispersion of α-Fe2O3 on NaY Zeolites

Yang Xun-Min; Zhang Bin; He He-Yong; Gao Zi   

  1. Department of Chemistry, Fudan University
  • Received:1989-07-19 Revised:1990-02-01 Published:1991-02-15
  • Contact: Gao Zi

摘要: 用草酸高铁铵浸渍NaY沸石, 并在高温下焙烧, 得到α-Fe_2O_3/NaY沸石体系。经XRD相定量外推法测定, α-Fe_2O_3在NaY沸石上的最大分散量为0.060 gα-Fe_2O_3/gNaY, 仅占α-Fe_2O_3在沸石表面密置单层量的5.5%。首次尝试用正电子寿命谱方法测定α-Fe_2O_3在沸石表面的最大分散量, 所得结果与XRD方法完全吻合。由程序升温还原方法发现沸石上α-Fe_2O_3的还原分两步进行, α-Fe_2O_3先还原成Fe_3O_4, 然后再还原成金属。α-Fe_2O_3分散相与沸石之间的强相互作用, 使这两个还原反应受到阻抑。

关键词: α-Fe2O3, NaY沸石, X光衍射, 正电子寿命谱

Abstract: The α-Fe_2O_3/NaY zeolite samples were prepared by impregnating NaY zeolite with ammonium ferrioxalate solution and calcining at high temperature. The maximum dispersion amount of α-Fe_2O_3 on NaY zeolite measured with XRD quantitative phase analysis is 0.060 gα-Fe_2O_3/gNaY, which is only 5.5% of the monolayer capacity of α-Fe_2O_3 on NaY according to a close-packed monolayer model. For the first time positron lifetime spectroscopy has been used to detect the dispersion amount of oxide on zeolite. The maximum dispersion amount of α-Fe_2O_3 obtained is fully consistent with that obtained from XRD phase analysis. TPR spectra of the samples show that the reduction of α-Fe_2O_3 on the zeolite consists of two steps, α-Fe_2O_3 is first reduced to Fe_2O_3 at low temperature and then to the metal at higher temperature. Both reduction reactions are ingibited by the strong interaction of the dispersed α-Fe_2O_3 phase with the zeolite.

Key words: α-Fe2O3, NaY zeolite, XRD, Positron lifetime spectroscopy