Abstract:

Fe 2O 3 K 2O Catalysts with different content of K 2O and calcined at different temperature were characterized by using Mossbauer spectroscopy. It was found from the experiments that only a sextuplet assignable to Fe 3+ of α Fe 2O 3 could be detected while the K 2O content in these catalysts were lower than 5%and the calcination temperature was below 900℃;and complex spectra ,which could be fitted with several sextuplets of trivalent irons present in α Fe 2O 3, KFeO 2, K 1+ x Fe 11 O 17 and α FeOOH ,and a doublet of Fe 3+ in γ FeOOH ,would be observed if the K 2O content were 10%～27%and the calcination temperature were 800～900℃. The γ FeOOH, as a hydrous iron oxide ,was the decomposition product of KFeO 2 which was strong hydroscopic by absorbing moisture from the atmosphere. The results also suggested that Mossbauer spectroscopy was a better mean than XRD for the characterizations of Fe 2O 3-K 2O catalysts,by which ,α-FeOOH ,γ-FeOOH and α Fe 2O 3 in amorphous or crystallite forms ( unable to be found by XRD ) could be detected . It was also shown from the Mossbauer spectroscopy and a TPR studies that potassium could retard the reduction of Fe(III) to Fe(II) in the Fe 2O 3 K 2O catalysts. 

Key words: Ethylbenzene, Dehydrogenation, Mossbauer, Iron catalyst