MOFs-Derived Fe–Co Bimetallic Catalyst for Selective CO2 Hydrogenation to Light Olefins

Abstract

The catalysis of CO₂ to light olefins (C₂⁼–C₄⁼) utilizing Fe–Co bimetallic catalysts is deemed a practicable approach to counteract the excessive emission of CO₂. However, a significant research gap exists in the study of manipulating the interaction between Fe–Co alloys, particularly in terms of component control. In this work, a range of bimetallic catalysts with varying Co/Fe molar ratios supported on ZrO₂ were obtained through pyrolysis of mixed metal organic framework NH₂-MIL-88B(Fe/Co)@UiO-66 that enables the hydrogenation of CO₂ to C₂⁼–C₄⁼. Notably, the catalyst 10Fe1Co@ZrO₂ exhibited a C₂⁼–C₄⁼ selectivity of 45% at a CO₂ conversion of 44.6%. The characterization results authenticate that, compared to the bare Fe catalyst, introducing Co significantly enhances the CO₂ adsorption and conversion. Intriguingly, CoFe₂O₄ formed in both 10Fe1Co@ZrO₂ and 5Fe1Co@ZrO₂ undergoes reduction to generate Co_xFe_y, facilitating its subsequent carbonization into the active phase χ-(Co_xFe_1–x)₅C₂ more readily during the reaction process.