Enhanced Conversion of Syngas to Gasoline-Range Hydrocarbons over Carbon Encapsulated Bimetallic FeMn Nanoparticles

Adjusting the hydrocarbon product distribution is the focus of the Fischer–Tropsch synthesis (FTS) reaction. A novel FeMn@C core–shell catalyst with bimetallic FeMn nanoparticles encapsulated in a carbon shell was synthesized by a one-step solvothermal method. In the FTS reaction, this catalyst exhibited higher catalytic activity and C5+ hydrocarbons (especially for 63.3% C5–12 gasoline range products) selectivity as well as excellent stability compared to the Fe@C or traditional FeMn/SiO2 catalyst. The superior activity could be attributed to the enrichment of Fe elements at the margin stemming from the replacement of central Mn species, promoting the formation of more active iron carbides by combining with the surrounding carbonaceous matter. Particularly, the “confinement effect” of the core–shell structure for FeMn@C facilitated the polymerization of light olefins produced by Mn-modified Fe nanoparticles, resulting in more heavy hydrocarbons and enhanced stability. This work showed new insights to develop a potential FTS catalyst candidate.