【摘要】 用TPP-原位穆斯堡尔谱联用技术考察了活性炭担载的铁催化剂的还原过程,该催化剂有四个还原峰,分别相应于Fe³⁺—→Fe₃O₄—→FeO—→Fe"的串行反应,及Fe³⁺—→Fe（x）（一种高分散还原态铁物类）的直接还原,各步骤的特征温度依次为410,530,640和770℃,活性炭上Fe³⁺的两个还原序列表明活性炭担体表面存在强弱不同的两类吸附中心,从而存在着铁物类与活性炭之间的两种不同强度的相互作用。此外,在TPR过程中观察到磁分裂Fe₃O₄向超顺磁Fe₃O₄的转化,表明可能存在着Fe₃O₄在活性炭表面的再分散过程。更多还原

【Abstract】 Reduction process of an activated carbon (Ac) supported iron catalyst was studied by a combined method of TPR and in situ Mo’ss-bauer spectroscopy. It was revealed that the reduction of Fe/Ac catalyst was more complicated than that of the unsupported iron due to the existence of metal-support interactions of different intensities between iron and Ac. For Fe/Ac catalyst, there are four peaks with characteristic temperature of 410, 530, 640, and 770℃ respectively in its TPR profile. Results of in situ MCssbauer studies (at room temperature) for each of the TPR peaks showed that the first three peaks were an indication of a consecutive reduction as follows: Fe (Ⅲ)→Fe3O4→FeO→ Fe(0),and the last peak corresponded to the direct reduction of Fe (Ⅲ) to a finely dispersed iron species Fe(x) which was characterized by a single peak of the Mossbauer spectrum with isomer shift of -0.10 mm/s. This suggests that two kinds of interaction exist between iron species and Ac. In addition, the increase in the area ratio of superpa-ramagnetic to magnetic Mossbauer spectra of Fe3O4 implied that Fe3O4 supported on Ac might undergo a redispersion during TPR of thecatalyst.更多还原