Catalytic properties of cobalt and nickel ferrites dispersed in mesoporous silicon oxide for ethylbenzene dehydrogenation with CO2

A polymeric precursor method was applied to synthesize catalysts of the general formula MFe2O4 (M = Co and Ni) in order to contribute to studies on ethylbenzene dehydrogenation in the presence of CO2. The catalysts were characterized by TG, H-2-TPR, XRD, Mossbauer spectroscopy (MS), N-2 adsorption/desorption isotherms and TPD-CO2. Investigations using XRD and MS revealed that the spinel structures of CoFe2O4 and NiFe2O4 phases were formed. The catalytic results suggested that materials with a spinel structure are particularly interesting for ethylbenzene dehydrogenation. Compared to the other catalysts synthesized the sample containing cobalt ferrite showed higher conversion and good styrene selectivity. The analysis of the spent catalyst (DRX) showed that the CoFe2O4 phase was stable under the reaction conditions and that a coke (TG) deposit was more pronounced for the NiFeSi.