Role of SiO2 in different iron-based catalysts for Fischer-Tropsch synthesis to light olefins

Co-precipitated FeSi-cp catalysts, impregnated FeSi-im catalyst and core-shell Fe@Si catalysts synthetized through different method were characterized by N-2 adsorption, ICP, XRD, TEM, H-2-TPR, CO-TPD, Mo center dot ssbauer spectroscopy and TG. The configuration between Fe and Si played an important role in the catalyst performance. Both FeSi-cp and FeSi-im showed high dispersion, but easily to be agglomerated in FTS. In contrast, Fe@Si has high crystallinity and strong CO chemisorption capacity, which is conducive to the formation of Fe5C2. The SiO2 shell could isolate the active components, reduce carbon deposition and restrain the production of C-5(+). The results of FTS performance revealed that core-shell Fe@Si catalysts show higher C-2(=)similar to 4= selectivity and better FTS stability in 120 h.

Automated summary

Co-precipitated FeSi-cp catalysts, impregnated FeSi-im catalyst, and core-shell Fe@Si catalysts synthesized through different methods were characterized using various techniques. The configuration between Fe and Si was found to significantly influence the catalyst performance. FeSi-cp and FeSi-im exhibited high dispersion but were prone to agglomeration in FTS reactions. On the other hand, Fe@Si displayed high crystallinity and strong CO chemisorption capacity, promoting the formation of Fe5C2. Additionally, the SiO2 shell in the core-shell structure prevented carbon deposition and inhibited the production of C-5(+) species. The FTS performance results demonstrated that the core-shell Fe@Si catalysts exhibited higher selectivity towards C-2(=)4= and better stability over a period of 120 hours.