Fe/Ru synthesized by hydrothermal deposition on hyper-crosslinked polystyrene as promising Fischer-Tropsch catalyst

Abstract

In this work, Fe/Ru-catalyst supported on hyper-crosslinked polystyrene (HPS) synthesized via hydrothermal deposition was proposed for the Fischer-Tropsch synthesis (FTS) to obtain a high yield of gasoline-ranged hydrocarbons. According to the characterization results, the obtained monometallic 2%Fe-HPS catalyst contains Fe₃O₄ particles with a multimodal distribution (mean particle size of 11, 30, and 45 nm). The addition of Ru leads to a decrease in the particle size with a narrower distribution (ca. 5 nm). Ru was shown to serve as a nucleating agent for Fe₃O₄ crystalline since it has a higher affinity to the HPS surface and strongly anchors to the benzene rings of the polymer. This prevents a leaching of the active phase from the support increasing the catalyst stability. Ru addition also brings supplemental sites for CO and H₂ chemisorption resulting in 1.5-fold increased activity in FTS reaction compared to monometallic 2%Fe-HPS composite. 2%Fe-1%Ru-HPS composite showed ∼20% higher selectivity toward the formation of C₅–C₁₁ alkanes at about 30% conversion of CO in comparison with monometallic one. Moreover, the branched hydrocarbons with a selectivity of approximately 17.5 mol% were observed in the FTS products in the presence of a 2%Fe-1%Ru-HPS catalyst.