A Core-Shell Structured Na/Fe@Co Bimetallic Catalyst for Light-Hydrocarbon Synthesis from CO₂ Hydrogenation

The direct CO₂ Fischer–Tropsch synthesis (CO₂-FTS) process has been proven as one of the indispensable and effective routes in CO₂ utilization and transformation. Herein, we present a core-shell structured Na/Fe@Co bimetallic catalyst to boost CO₂ conversion and light hydrocarbon (C₂ to C₄) selectivity, as well as inhibit the selectivity of CO. Compared to the Na/Fe catalyst, our Na/Fe@CoCo-3 catalyst enabled 50.3% CO₂ conversion, 40.1% selectivity of light hydrocarbons (C₂-C₄) in all hydrocarbon products and a high olefin-to-paraffin ratio (O/P) of 7.5 at 330 °C and 3.0 MPa. Through the characterization analyses, the introduction of CoCo Prussian Blue Analog (CoCo PBA) not only increased the reducibility of iron oxide (Fe₂O₃ to Fe₃O₄), accelerated the formation of iron carbide (Fe_xC_y), but also adjusted the surface basic properties of catalysts. Moreover, the trace Co atoms acted as a second active center in the CO₂-FTS process for heightening light hydrocarbon synthesis from CO hydrogenation. This work provides a novel core-shell structured bimetallistic catalyst system for light hydrocarbons, especially light olefin production from CO₂ hydrogenation.