Synthesis, Characterization, and Catalytic Performance of Fe-Cr Nano Oxide/ZSM-5 Composites for Styrene Production

In this article, at first ZSM-5 zeolite using metakaolin as a source of alumina was synthesized by using a microwave oven. In this regard, ZSM-5 zeolites with high purity and in relatively short time (25 min with microwave irradiation) were successfully prepared. Then nano particle Fe-Cr/ZSM-5 zeolite composite catalysts were prepared via Solid State Dispersion (SSD) and encapsulation methods. Samples were prepared by mixing different weight ratios of Fe2O3, Cr2O3, and K2CO3 powders with ZSM-5 zeolites at the first method, and for the second one, the metal complexes were encapsulated within the ZSM-5 zeolite pores. Prepared catalysts then characterized via EDX, SEM, XRD and FT-IR techniques. The catalytic performance of the synthesized catalysts was evaluated in ethylbenzene dehydrogenation to styrene in the presence of steam at 610 °C under atmospheric pressure. The results demonstrate that ZSM-5 oxide loaded catalysts have better performance than bare zeolite. And also samples with Fe2O3 nano particles act more effectively than Cr2O3 loaded zeolites. It was shown that styrene yield was significantly been influenced by loading Fe2O3, Cr2O3 and K2CO3 materials. The comparison between performance of SSD and encapsulation method was shown that the second one with smaller particle size and high Fe-Cr oxide dispersion has higher yield and conversion toward styrene production.