Synthesis of Ag promoted porous Fe3O4 microspheres with tunable pore size as catalysts for Fischer–Tropsch production of lower olefins

•Ag promoted porous microspheres were synthesized.•The pore size of microspheres was controllable.•The introduction of Ag could regulate the dispersion of Fe.•Smaller pore size exhibited high selectivity to C2–4 olefins and low to CH4.

Ag promoted porous Fe3O4 microspheres with tunable pore size were synthesized via one-pot solvothermal method and employed as catalysts for Fischer–Tropsch synthesis. The introduction of Ag played an important role in regulating the pore size of catalysts and the dispersion of Fe. Comparable to unmodified catalyst in this system, Ag promoted Fe-based catalysts displayed excellent selectivity to lower olefins, particularly for Fe–0.9Ag with smaller pore size of 1.33 nm and Fe dispersion of 10.1%. The maximum selectivity to C2 through C4 olefins was 43.0 wt.%, and the selectivity to CH4 was low to 14.8 wt.%.

Graphical abstractAg promoted porous Fe3O4 microspheres with tunable pore size were synthesized using one pot solvothermal method and employed as catalysts for Fischer–Tropsch synthesis. Pore size determined confined space impedes hydrogenation and transportation of long chain hydrocarbon, but facilitates hydrogen abstraction and chain growth via inserting CH2 groups to form olefins, particularly for C2–4 olefins. Furthermore, the effect of dispersion of Fe on lower olefin selectivity was also discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide