Reductive Activation of Mono‐ and Bimetallic Fe and Co Catalysts for CO Hydrogenation: Unusual Formation of Fe _0.88 Co _0.12 Phase and Synergistic Effect in the Catalysis

ABSTRACT This study investigates the reductive activation of silica‐supported mono‐ and bimetallic iron and cobalt catalysts for CO hydrogenation. The focus is on the formation of active phases and their catalytic performance in Fischer–Tropsch synthesis (FTS). Using a combination of x‐ray diffraction, Mössbauer spectroscopy, x‐ray photoelectron spectroscopy, and temperature‐programmed reduction (TPR) with magnetometry, we identified an unusual Fe 0.88 Co 0.12 solid solution phase during reductive activation in a CO/H 2 flow. The presence of cobalt was found to inhibit iron carbide formation, while iron impedes the complete reduction of cobalt oxides. Catalytic testing was performed under typical FTS conditions (20 bar, 240°C, CO:H2 = 1:1). The bimetallic FeCo/SiO 2 catalyst exhibited superior activity and hydrocarbons productivity compared to its monometallic counterparts. These findings highlight the potential of Fe─Co bimetallic systems for optimizing FTS performance, and provide valuable insights into the role of alloy formation in the catalytic performance.