非担载铁-钼催化剂在氢还原过程中的物相研究

A Study on the Phases of Unsupported Iron-Molybdenum Catalyst During Reduction in Hydrogen

本文利用原位穆斯堡尔谱和XRD研究了10%Fe/MoO_3催化剂在氢还原过程中铁和钼的物相及其变化.结果表明.在铁和钼还原的同时,它们之间的相互作用增强,使得在350℃—500℃的温度范围内.升高还原温度,催化剂的还原度反而下降.在350℃铁可部分地还原为零价,这时钼仅还原为MoO_2在500℃,钼开始还原到零价.这时还原生成的Fe^0形成Fe-Mo合金,在550℃铁和钼全部还原为零价,铁以Fe-Mo合金存在,其穆斯堡尔谱显示精细结构.

In-situ Mossbauer spectroscopy and X-ray diffraction (XRD) have been used to study the phases of unsupported iron-molybdenum catalyst (10%Fe/MoO3) during reduction in hydrogen. The results showed that the interactions between the oxides of iron and molybdenum increased when they underwent reduction in H2, so that in the range from 350℃ to 500℃ the reduction degree of the catalyst decreased with the increase of reduction temperature. The results also showed that, at 350℃ iron could be partly reduced to metal while molybdenum was only reduced to MoO2. At 500℃, molybdenum started to reduce to metal and an Fe-Mo alloy was formed at the same time. At 550℃ , all the iron and molybdenum in the catalyst could b e reduced to metal and all the Fe0 existed as an Fe-Mo alloy, which showed a singlet in its Mossbauer spectrum when it was recorded at a high velocity and a fine structure when it was recorded at a low velocity.