Surface modification of Fe-based catalysts for promoting highly selective linear α-olefin formation in Fischer-Tropsch synthesis

Fischer-Tropsch synthesis (FTS) is a pivotal technology for sustainable production of chemicals from non-fossil resources. However, the design of catalysts to tailor product distribution, particularly to enhance olefin selectivity, remains an enduring challenge. Herein, we report an iron-based catalyst modified with oxygen-containing groups, Fe₃O₄/HEC (hydroxyethyl group-modified), which demonstrates extraordinary catalytic performance in FTS without any alkali metal promoters. This catalyst exhibits high activity, achieving 41.36 % light olefin (C₂-C₄⁼) selectivity and an O/P ratio of 5.49. Meanwhile, the C₅⁺ hydrocarbon selectivity reaches 40.38 % (with 68.2 % linear α-olefins). The modified catalyst promotes the formation of iron carbides and facilitates the coupling of *CH_x to promote chain growth while suppressing secondary hydrogenation reactions, which is considered to account for the high selectivity toward olefins and heavy hydrocarbons.