High-yield production of liquid fuels in CO2 hydrogenation on a zeolite-free Fe-based catalyst.

Abstract

Catalytic conversion of CO2 to long-chain hydrocarbons with high activity and selectivity is appealing but hugely challenging. For conventional bifunctional catalysts with zeolite, poor coordination among catalytic activity, CO selectivity and target product selectivity often limit the long-chain hydrocarbon yield. Herein, we constructed a singly cobalt-modified iron-based catalyst achieving 57.8% C5+ selectivity at a CO2 conversion of 50.2%. The C5+ yield reaches 26.7%, which is a record-breaking value. Co promotes the reduction and strengthens the interaction between raw CO2 molecules and iron species. In addition to the carbide mechanism path, the existence of Co3Fe7 sites can also provide sufficient O-containing intermediate species (CO*, HCOO*, CO3 2*, and ) for subsequent chain propagation reaction via the oxygenate mechanism path. Reinforced cascade reactions between the reverse water gas shift (RWGS) reaction and chain propagation are achieved. The improved catalytic performance indicates that the KZFe-5.0Co catalyst could be an ideal candidate for industrial CO2 hydrogenation catalysts in the future.