Ce-promoted Fe-K-Mg catalyst and its application in dehydrogenation of ethylbenzene

Abstract

The continuous pursuit of green, low-carbon, and efficient processes in catalysis necessitates a deep understanding of catalytic reaction mechanisms and the structure-performance relationship of catalysts. Styrene, a vital monomer in the chemical industry, is primarily produced through the catalytic dehydrogenation of ethylbenzene over Fe-based catalysts. This study prepared a series of Fe-K-Mg catalysts promoted with different CeO2 contents. Various techniques such as mercury intrusion, particle strength tests, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, Mössbauer spectroscopy, and temperature-programmed techniques were employed to characterize the catalysts' physical properties, surface, and bulk structures. The results indicate that the bulk density and crush strength of the catalyst are closely related to the pore structure and grain size of potassium β-ferrite. The surface of the Ce-promoted catalyst contains potassium β-ferrite KFe11O17, cerium dioxide, and potassium carbonate, while the bulk structure consists of potassium β-ferrite and cerium dioxide. The addition of Ce enhances the catalytic activity of ethylbenzene dehydrogenation, but the selectivity of styrene shows the opposite trend. The Fe-K-Mg catalyst containing 12% CeO2 exhibited the highest single-pass yield of styrene, reaching 70.9%. This study also discusses the possible effect of CeO2 on the performance of the Fe-K-Mg catalyst for ethylbenzene dehydrogenation.