Regulating Iron Species Compositions by Fe-Al Interaction in Co2 Fischer-Tropsch Synthesis
28 Pages Posted: 23 Mar 2022
Abstract
Different iron species exhibit distinct activity and selectivity in CO 2 Fischer-Tropsch synthesis. Herein, by controlling calcination temperature, Fe-Al interaction in Na promoted Fe-Al catalysts has been regulated, which further leads to various compositions of iron oxide (FeO x ) and iron carbides (Fe 7 C 3 and Fe 5 C 2 ) after CO activation and CO 2 hydrogenation reaction. The phase compositions and structures of Fe-Al catalysts are carefully distinguished by multiple characterizations, including XRD, XPS, MES and TEM, and the reactivity of different phases is studied with the combination of experiments (kinetics, TP and in situ DRIFTS) and Density Functional Theory (DFT) calculations. Our FeAl350 with the highest FeC x content shows the highest CO 2 conversion of 48.2% and the lowest CO selectivity of 10.1%, and FeAl900 with the highest Fe 5 C 2 / FeC x ratio presents the highest C 5+ selectivity of 44.6%. Finally, a correlation between different compositions of iron species with the activity and selectivity of Fe-based for CO 2 Fischer-Tropsch synthesis (CO 2 -FTS) was established.
Keywords: CO2 hydrogenation, Fe-Al interaction, Iron oxide, iron carbide
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