<p>Co-Fe bimetallic catalysts have attracted increasing attention in the field of Fischer–Tropsch synthesis (FTS). In this study, cobalt was supplied in the form of Co₃O₄ nanoparticles, and three different methods of iron (Fe) incorporation were employed: (1) Fe modification of the Al₂O₃ support prior to Co₃O₄ loading (Co/Fe-Al₂O₃), (2) co-loading of Fe and Co₃O₄ (CoFe/Al₂O₃), and (3) Fe modification of Co₃O₄ prior to loading (Co-Fe/Al₂O₃). These model catalysts were used to investigate the interactions between Co, Fe and the support and their impact on the catalytic activity and product selectivity of FTS. The results showed that the addition of Fe promotes cobalt reduction, modifies H₂ and CO adsorption properties and regulates catalytic performance. Compared with Co/Al₂O₃, Co/Fe-Al₂O₃ exhibited the best reducibility and significantly reduced CH₄ selectivity from 19.2 to 11.2%. However, its CO adsorption weakened, decreasing CO conversion from 25.3 to 21.4%. Co-Fe/Al₂O₃ showed enhanced H₂ and CO adsorption, increasing CO conversion by 18.9%. These findings demonstrate that the location of Fe affects the metal-support interaction, reducibility and adsorption activation abilities of the Co catalyst, ultimately altering FTS activity and selectivity.</p> Graphical Abstract