ε-Iron carbide as a low-temperature Fischer–Tropsch synthesis catalyst

ε-Iron carbide has been predicted to be promising for low-temperature Fischer–Tropsch synthesis (LTFTS) targeting liquid fuel production. However, directional carbidation of metallic iron to ε-iron carbide is challenging due to kinetic hindrance. Here we show how rapidly quenched skeletal iron featuring nanocrystalline dimensions, low coordination number and an expanded lattice may solve this problem. We find that the carbidation of rapidly quenched skeletal iron occurs readily in situ during LTFTS at 423–473 K, giving an ε-iron carbide-dominant catalyst that exhibits superior activity to literature iron and cobalt catalysts, and comparable to more expensive noble ruthenium catalyst, coupled with high selectivity to liquid fuels and robustness without the aid of electronic or structural promoters. This finding may permit the development of an advanced energy-efficient and clean fuel-oriented FTS process on the basis of a cost-effective iron catalyst. ε-Iron carbide is a promising catalyst for low-temperature Fischer–Tropsch synthesis but is difficult to synthesize. Here, the authors report a rapid-quenching process for the synthesis of nanocrystalline ε-iron carbide, and evaluate the catalytic activity and selectivity of the material.