【摘要】 用浸渍法制备了含3％Fe₂O₃的载体为γ-Al₂O₃的负载型氧化铁催化剂,并用MB,TEM,ESCA和AES对该催化剂在水煤气变换反应的各个阶段进行了测试。结果表明,在反应前催化剂上存在一种类似于FeAlO₃的含Fe³⁺和Al³⁺的表面氧化物。在反应条件下还原后,同时存在类似于FeAlO₃,FeAl₂O₄和Fe₃O₄的表面化合物,并且铁离子的分散度也提高了。更多还原

【Abstract】 The catalyst containing 3 % by weight of Fe2O3 supported on r-Al2O3 was prepared by impregnation of γ-A12O3 with a solution of ferric nitrate, and subsequently dried at 373K and calcined at 823 K for 5 hr. Catalyst samples at various steps in the water-gas shift reaction, in which the interaction between the active component and the support occurred, have been studied by MB, BET, TEM, ESCA and AES.A six-line Mossbauer spectrum containing a superimposed doublet of the calcined catalyst before reaction could not be used to distinguish FeAlO3 from Fe2O3. X-ray diffraction study also failed to show the presence in the sample of any species other than r-Al2O3. The difference between the properties of oxygen atoms in the catalyst sample and in γ-A12O3 or Fe2O3 demonstrated by AES suggested that the interaction between Fe2O3 and γ-Al2O3 had occurred and a new surface compound was produced. The ESCA study showed that this surface compound containing Fe3+ and A13+ similar to FeAlO3.Mossbauer spectra without the six-line attributed to large antiferromagnetic particles were recorded at various steps in the water-gas shift reaction. Both Fe3O4 microcrys-tallites and a surface compound containing Fe2+ and A13+ which was analogous to FeAl2O4 might be formed and this inference was supported by the ESCA investigations, meanwhile the iron ions were further dispersed. The interaction between the active component and MgO support was somewhat stronger than that between the active component and γ-Al2O3.更多还原