In this study, the research team chose the CO-intermediate pathway, induced Cu sites with the capability of non-disassociation adsorption of CO, and synthesized the Cu-Fe catalyst with copper-iron carbide interfaces working under ambient pressure. The Cu-Fe catalyst, composed of Cu, iron oxides, and iron carbides, is termed activated CuFeO₂. 

They found that the activated CuFeO₂ achieved long-chain olefins selectivity of 66.9% under 1 bar, which surpassed the current highest selectivity of 66.8% under 35 bar.

Compared to the traditional iron-based catalyst, the Cu-Fe catalyst showed lower selectivity for CO and methane and higher selectivity for long-chain olefins.

To evaluate the applicability of the activated CuFeO₂, they changed the space velocity and the ratio of H₂ to CO₂. The results showed that the prepared catalysts could achieve good long-chain olefins selectivity under various space velocities and the ratio of H₂ to CO₂, indicating the applicability of activated CuFeO₂ in a wide range of conditions.

"Although the activity of the catalyst decreased after a long reaction, it can be refreshed by a regeneration process that increased the pressure," said Prof. ZENG.

Moreover, the researchers revealed that except for the C-C coupling through the carbide process on iron carbide, CO insertion also occurred on copper-iron carbide interfaces to cause carbon chain growth.

As a result, a large amount of undissociated CO on the surface of the catalyst can be utilized efficiently. The cooperation of the carbide process and the CO insertion process led to the good selectivity of long-chain olefins.