STUDY ON THE PREPARATION OF K-C-FE AL2O3 CATALYSTS FOR AMMONIA-SYNTHESIS AT MILD CONDITIONS FOLLOWED BY MOSSBAUER-SPECTROSCOPY/

The state of iron in novel K-C-Fe/Al2O3 catalysts for ammonia synthesi s at mild conditions was studied by Mossbauer spectroscopy and X-ray d iffraction. The activities of the catalysts were found to be comparabl e or even higher than the activity of the commercial contact. Two cata lysts differing in iron loading were examined after every stage of pre paration. The high (ca. 33 wt.%) and low (ca. 11 wt.%) Fe content resu lted in a different behavior of iron during the catalyst preparation a nd different iron forms were found in the active contacts. In the cata lyst with high iron loading the difference in Fe dispersion was observ ed while the low loading contact contained mainly Fe(III) species. Bot h highly dispersed iron and Fe(III) species were influenced by potassi um, this being concluded from the Mossbauer parameters calculated for these forms.