Highly selective light olefin production via photothermal Fischer–Tropsch synthesis over α/γ-Fe2O3-derived Fe5C2 under low pressure

Abstract

Fischer–Tropsch synthesis is a petroleum-independent technology for converting syngas into value-added products, such as light olefins containing two to four carbon atoms, liquid fuels of alcohols or high alkanes. However, the wide product distribution has still limited the application of this technology because of the high cost of product separation. The high reaction temperature and pressure cause great energy consumption, which is another shortcoming of Fischer–Tropsch synthesis. Herein, we present a photothermal Fischer–Tropsch synthesis driven by solar light under low pressure. The catalyst α/γ-Fe₂O₃-derived Fe₅C₂ achieves a selectivity for light olefins as high as 71.9%, and the olefin/paraffin ratio for C₂–C₄ reaches 16.7. The high selectivity for light olefins over this catalyst can be attributed to the in situ photothermal synthesis, which modulates the exposed crystal facet of Fe₅C₂. This work demonstrates an approach for regulating the phase composition of the pre-catalyst to promote the selectivity of the catalyst and provides an alternative strategy for rationally designing efficient catalysts.