Influence of Cerium on the transformation of hematite and its reactivity in a reducing atmosphere

Abstract

It is known that cerium compounds are widely used as promoters in the iron-potassium catalysts for alkylaromatic and olefinic hydrocarbons dehydrogenation. To establish the mechanism and the role of cerium oxide in the formation of catalytically active phases (ferrite potassium) must first to determine its effect on the transformation and reactivity of the iron oxide containing in the catalyst in an amount of 50–80 %, and participating in ferrite formation. There is the studying of thermal behavior at heating in air of cerium oxalate and Fe2O3–CeO2 model system, which are the main components in the manufacture of iron-potassium catalysts, by X-ray, thermal, analysis of variance, low-temperature nitrogen adsorption and temperature-programmed reduction with hydrogen. A great lability of cerianite compared with hematite is identified. It is established that the introduction of cerium into hematite increases the reactivity of the Fe2O3–CeO2 system and its thermal heating leads to a partial reduction of Fe2O3. The results obtained will be used for development a new iron-potassium catalysts with improved catalytic activity in the dehydrogenation reaction of isoamylenes to isoprene.