Alumina restructure iron

Fig. 3.54 The deactivation of the oxygen restructureed (110) iron surface along with the restructured (110) iron surface with alumina added ...

Except for these, there are at least two other types of surface models for iron catalysts in literature.The first one considered that the existence of alumina on the iron surface results in the restructuring of the surface and forms the atomic aluminium on the surface. After being exposed to the reaction mixture, iron will grow along with the orientations of (111) and (211) to iron-aluminium. The second one considered that the promoters are present on the surface by a thickness smaller than one nanometer and with an approximate diameter of two nanometers, which are seperated by the pure irons. However, none of the models can explain every experimental observation. 

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